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S0968090X20307361 | This paper proposes a novel combination of machine learning techniques and discrete choice models for route choice modeling . The data driven choice set generation method identifies routes characteristics by clustering and implicitly generates the choice set by sampling route characteristic attributes from the clusters . Important features are selected by random forests for route choice model development . With the selected features the methodological iterative approach is applied to specify the utility functions and to find significant explanatory variables automatically . | Combination of machine learning and discrete choice for route choice modeling. Data driven choice set generation method. Important features from Random Forests for route choice model development. Methodological iterative approach applied to find significant explanatory variables automatically. High prediction accuracy. |
S0968090X20307373 | In recent years there has been a tremendous change in the landscape of mobility offerings with the introduction with the introduction of Uber and Lyft companies collectively known as Transportation Network Companies otherwise known as ridesourcing companies . Due to the nascency of these companies there is a small but rapidly growing body of literature on the impacts these TNCs are having on traditional forms of shared ride modes however most of the emerging literature centers on the relationships between TNC and only one other shared mode of transportation . This research attempts to contribute to the literature by examining the relationship between TNCs and multiple shared ride modes simultaneously . To this end a joint modeling framework was used to study New York City ridership data for TNCs taxi services bikesharing and the subway from January 2015 to June 2017 . The goal of the research presented is two fold explore the dynamic relationships between TNCs and other modes of shared ridership as well as to build a predictive model for the daily ridership usage for each modal offering and total daily ridership usage . To accomplish these tasks we first used a | Exploration of ridesourcing market dynamics in New York City using multivariate time series. Discovery of possible substitutionary and complementary relationships between TNC and incumbents modes. Application of multivariate time series in the ridesourcing domain. |
S0968090X20307385 | The problem of stop detection is at the base of many current and upcoming smartphone based travel survey technologies and directly impacts the quality of many downstream operations . The inference of departure arrival time mode and purpose of a trip for example rely on the stop motion patterns represented by smartphone sensor data . As users handle smartphones for various purposes and their preferences determine different device positions while traveling accelerometer and gyroscope for instance often present ambiguities that prevent accurate stop detection . | We investigate the stop detection problem in smartphone based travel surveys based on 1.4 million GPS observations. We propose a novel GPS GIS data fusion represented as a multi dimension tensor. We design optimise and benchmark a number of ANN classifiers for alternative fusion representations. We show that CNN RNN applied to the preposed fusion representation is the best performer especially with noisy GPS. |
S0968090X20307403 | This paper presents a study in investigating the generational gaps between Millennials and GenerationXin terms of their mobility attitudes . A comprehensive analytical framework was proposed in this study and applied to data obtained from an SP survey in the U.S. Four modeling steps were involved to measure the attitudes identify generational gaps recognize potential contributors to the attitudes and decompose the contributions into | A modeling framework was developed to investigate the generational gaps in mobility attitudes. BlinderOaxaca decomposition identified the sources of attitude gaps between Generations X and Y. Millennials have more favorable views toward shared mobility transit and automated vehicles. A dominant portion of the gaps stemmed from the different perspectives between the generational cohorts. The differences in the SED attributes explained a small portion of the generational gaps. |
S0968090X20307415 | Fully automated vehicles have the potential to drive empty . For privately owned AVs such empty repositioning has the potential benefit of avoiding parking costs at their destination . AV owners could have their vehicle drop them off at their destination then drive elsewhere to park . Although previous studies have considered the congestion effects of AVs repositioning to park at their owners residence this study models the choice of parking location when AVs reposition away from the travelers destination . We model this behavior through a modified static traffic assignment with a logit model for destination choice in which AV passenger carrying trips can create a second empty repositioning trip to an alternate parking zone . The traffic assignment is formulated as a variational inequality . Numerical results on the Chicago sketch network show the effects of AV market penetration fuel costs and parking fees on the number of repositioning trips as well as the impacts of repositioning trips on network congestion . Next we study the problem of adjusting zone specific parking costs to influence the repositioning behavior . In particular when zones have asymmetric parking infrastructure costs optimized parking fees combined with empty repositioning can encourage AVs to park at cheaper locations thus reducing the land used for parking at zones with high land value . This network design problem is formulated as a bi level program . Since it is bi level and non convex a genetic algorithm is used to find a good solution . Results on the Sioux Falls test network show that the adjusted parking costs are effective at reducing the congestion caused by empty repositioning and encouraging more optimal parking choices for repositioning AVs . | Static traffic assignment with destination choice for automated vehicle parking. Empty repositioning at varying market penetrations and demands affects congestion. Network design problem of adjusting parking costs and available parking spaces. Genetic algorithm is effective at encouraging more optimal parking behavior |
S0968090X20307427 | This paper proposes a hierarchical Bayesian network model to quantitatively evaluate the resilience of urban transportation systems . Based on systemic thinking and taking a sustainability perspective we investigate the long term resilience of the road transportation systems in four cities in China from 1998 to 2017 namely Beijing Tianjin Shanghai and Chongqing respectively . The model takes into account various factors collected from multi source data platforms involved in stages of design construction operation management and innovation in road transportation systems . We test the model with the forward inference sensitivity analysis and backward inference . The result shows that the overall resilience scores of all four cities transportation systems are within a moderate range with values between 49 to 59 . Although they all have an ever increasing economic level the levels of transportation resilience in Beijing and Tianjin decrease first and then gradually increase in a long run which indicates a strong multi dimensional dynamic and non linear characteristic in resilience economic coupling effect . Additionally the results obtained from the sensitivity analysis and backward inference suggest that decision makers should pay more attention to the capabilities of quickly rebuilding and making changes to cope with future disturbances . As an exploratory study this study clarifies the concepts of long term multi dimensional resilience and specific hazard related resilience and provides an effective decision support tool for stakeholders when building resilient infrastructure . | A novel BNM is proposed to evaluate multi faceted transportation resilience. Forward inference sensitivity tests and backward inference are conducted. Long term transportation resilience is highly dynamic in the tested cities. The coupling effects of resilience with economic level is not always linear. Abilities to rebuild and adapt through reconfiguration are of importance. |
S0968090X20307439 | Lane change prediction can reduce traffic accidents and improve traffic flow . To predict lane changes variables which describe lane changes are needed . Recent studies used different classifiers and different inputs for lane change classification and prediction . Here different methods are used to extract the relevant input variables from a data set which was generated from a naturalistic driving study in the urban area of Chemnitz Germany . First variables which show different characteristics for left and no lane changes were chosen . The variables contained driver attributes environment attributes and vehicle attributes . Second different combinations of these input variables were analyzed with the principal component analysis . In the end the best combinations were used to classify left lane changes with an Echo State Network and a feedforward neural network . The Echo State Network achieved high area under the curve values true positive rates and low false positive rates for the classification with a majority of the input combinations . The feedforward neural network predictions were inferior of those to the Echo State Network . | Extensive variable selection to extract the relevant variables to predict divers lane changes. Using the principal component analysis for variable selection. Prediction of the lane change of drivers using the resulting promising variables. Comparison between the results of this paper and papers which used the same data set. |
S0968090X20307440 | Connected vehicles is an important intelligent transportation system to improve the traffic performance . This paper proposes two parallel computation algorithms to solve a large scale optimal control problem in the coordination of multiple connected vehicles . The coordination is formulated as a centralized optimization problem in the receding horizon fashion . A decentralized computation network is designed to facilitate the development of parallel algorithms . We use Taylor series to linearize non convex constraints and introduce a set of consensus constraints to transform the centralized problem to a standard consensus optimization problem . A synchronous parallel algorithm is firstly proposed to solve the consensus optimization problem by applying the | A parallel computation algorithm for large scale optimal control of CAVs is proposed. The coupling constraints is decomposed with consensus optimization and ADMM. The algorithms time complexity is independent to vehicle numbers. An asynchronous version ADMM is proposed based on our parallel algorithm. The convergence of the asynchronous ADMM is proved in theory. |
S0968090X20307452 | This paper shows how traffic heterogeneity and the way it is encoded into a model drastically affects a model ability to reproduce observed traffic . Being heterogeneity a major source of uncertainty to correctly frame the proposed validation methodology we have first reviewed and adapted cross disciplinary theoretical concepts about uncertainty modelling to traffic simulation . A number of open issues including error compensation and model overfitting has been interpreted and clarified through the proposed framework . A two level probabilistic approach has been applied to run stochastic simulations of three NGSIM I 80 traffic scenarios and quantitatively infer the impact of heterogeneity . According to this approach both the car following and the lane changing models of each vehicle have been calibrated against observed trajectories . Based on the estimated parameters distributions different models of heterogeneity have been quantitatively validated against macroscopic traffic patterns . Being traffic a collective phenomenon emerging from microscopic interactions even models calibrated on microscopic trajectories need to be quantitatively validated on macroscopic traffic patterns too . Among other results normal distributions of the model parameters which are customarily applied in traffic simulation practice have been found unable to reproduce the observed congestion patterns . Parameters correlation being claimed as highly influential in previous works is responsible for a model overfitting in traffic scenarios with low congestion . In the end it has been demonstrated that a thorough characterization of parameters heterogeneity can not be left out in traffic simulation if an ersatz representation of traffic is to be avoided . | Quantitative validation of microscopic models on traffic patterns from trajectories. Comprehensive review of uncertainty management in traffic modelling. Two level probabilistic approach to evaluate impact of drivers heterogeneity. Independent uniform pdfs resulted the most robust parameters distribution. The higher the congestion the higher the relevance of parameters correlation. |
S0968090X20307464 | Automation and electrification are inevitable trends in the development of intelligent vehicles . It is envisioned that automated electric taxis will play an important role in future transportation systems for serving personalized travel demands . To tackle the operational challenges caused by the high spatiotemporal heterogeneity of customer demands entails novel online strategy to intelligently manage AET fleet . This study proposes an | Automated electric taxis. Online operations. High spatiotemporal heterogeneity of customer demands. A two step reinforcement learning framework. A combinational optimization. |
S0968090X20307476 | Accurate information of path followed by vehicles at several real life scenarios is essential for modeling and testing the optimal path for autonomous vehicles analyzing the lateral dynamics such as lane changing and overtaking vehicle dynamics at the horizontal curves intersections and roundabouts . Recently the availability of such data is plenty thanks to the advancements in drone and computer vision technologies . Nevertheless extracting useful information from the observed data requires certain pre processing that can handle the noises added at several stages of the data collection . The adequacy of the existing off the shelf smoothing techniques for denoising the trajectory data of the modern era is certainly a question . The motivation for the present study is twofold . Firstly the challenges of contemporary trajectory data collection and associated error patterns are relatively unknown and thus an appropriate denoising technique needs to be developed . Secondly many of the existing smoothing techniques have chosen invariant parameters across all the vehicle paths even though the error patterns are dissimilar across the vehicles and in the longitudinal and lateral directions . Thus an adaptive smoothing needs to be applied for each observed vehicle path and its components . The present study proposes an adaptive and data driven path smoothing technique that can be universally applied to the video based path data obtained from any camera platform . The proposed reconstruction framework works in three stages in the first stage the data is prepared by resampling any missing data . Also any outlier in the observed path data is identified and removed at this stage . In the second stage a Recursively Ensembled Low Pass filter is proposed to handle the heavily tailed noise found in the video processing based trajectory data particularly for drone videos . A robust adaptive Gaussian kernel smoothing is applied in the third stage to have a localized reconstruction . For Kernel smoothing the smoothing parameters such as the optimal bandwidth and polynomial order are estimated using the proposed grid search algorithm . The parameter estimation process ensures that the bias and variance are perfectly traded off to achieve a smooth vehicle path . The performance evaluation of the proposed method shows an internally and physically consistent trajectory reconstruction . | Adaptive and data driven path smoothing technique. Recursively Ensembled Low Pass RELP filter for heavily tailed noise. Robust adaptive Gaussian kernel smoothing for a localized reconstruction. Preserves the actual vehicle dynamics maintaining internal and physical consistency. |
S0968090X20307488 | It is concerned that system level benefits of connected automated vehicle control might only prevail in a far future centralized control environment whereas the benefits could be much offset in a near future decentralized control system . To address this concern this paper proposes a decentralized control model for connected automated vehicle trajectory optimization at an isolated signalized intersection with a single lane road where each connected automated vehicle aims to minimize its own travel time fuel consumption and safety risks . To improve the computational tractability the original complex decentralized control model is reformulated into a discrete model . A benchmark centralized control model is also formulated to compare with the decentralized control model . The DIRECT algorithm is adopted to solve the above models . Numerical results show that the decentralized control model has better computational efficiency than the centralized control model without significant loss of the system optimality . Finally analysis on connected automated vehicle market penetration shows that the extra benefit of the centralized control model is not obvious either in under saturated traffic or at a low connected automated vehicle market penetration rate in critically saturated and over saturated traffic . The results suggest that as apposed to the earlier concern the near future decentralized control scheme that requires less technology maturity and infrastructure investment can achieve benefits similar to the far future centralized control scheme with much simpler operations in under saturated traffic or in critically saturated traffic and over saturated traffic with a low connected automated vehicle market penetration rate . | Propose a decentralized connected automated vehicle trajectory optimization model. Consider travel time fuel consumption and safety risks simultaneously. Consider mixed traffic containing connected automated and human driven vehicles. Compare the decentralized optimization model with a centralized optimization model. |
S0968090X2030749X | The rapid proliferation of smart personal technologies has given birth to smart Transportation Demand Management systems that can give personalized incentives to users . This personalization capacity builds on accurate modeling of user behaviors however in practice a users behavior data is often limited and his preferences in the discrete choice making process may change or evolve . In this paper we propose a new online updating model that can accurately and efficiently estimate an individuals preferences from his discrete choices . Our model is built on the concept of canonical structure where a set of canonical models are identified as the common preference patterns shared by the whole population and a membership vector is also identified for each individual to capture the degrees of the resemblance of his preferences to those common preference patterns . To allow preference to vary in the choice making process a time varying model can be integrated with the canonical structure . In the current study we use a simple cubic polynomial model with a single variant and show the detailed formulation of the integrated model . An online updating strategy is also proposed such that it is possible to update the parameters partially in practice . The proposed model is suitable for modeling a heterogeneous population with insufficient data from each individual . Both simulation studies and a real world application are taken in the current study . The results show that comparing with other frequently used models the model we proposed has the highest accuracy in preference learning and behavior prediction . | We develop a model to learn an individuals preference in sequential choices. The proposed approach is able to capture preference changes. The proposed approach permits learning from limited data. An online updating strategy is proposed to effectively update the estimates. |
S0968090X20307506 | The biggest challenge of analysing network traffic dynamics of large scale networks is its complexity and pattern interpretability . In this work we present a new computationally efficient method inspired by human vision to reduce the dimensions of a large scale network and describe the traffic conditions with a compact scalable and interpretable custom feature vector . This is done by extracting pockets of congestion that encompass connected 3D subnetworks as 3D shapes . We then parameterize these 3D shapes as 2D projections and construct parsimonious feature vectors from these projections . There are various applications of these feature vectors such as revealing the day to day regularity of the congestion patterns and building a classification model that allows us to predict travel time from any origin to any destination in the network . We demonstrate that our method achieves a 44 accuracy improvement when compared against the consensus method for travel prediction of an urban network of Amsterdam . Our method also outperforms historical average methods especially for days with severe congestion . Furthermore we demonstrate the scalability of the approach by applying the method on the entire Dutch highway network and show that the feature vector was able to encapsulate the network dynamics with a 93 prediction accuracy . There are many paths to further refine and improve the method . The compact form of the feature vector allows us to efficiently enrich it with more information such as context weather and event without increasing the computational complexity . | Reduced the traffic dynamics of a large scale network into a small feature vector. Feature vector is composed of congestion pockets parameterized using shapes and its variations. Demonstrated on the urban network of Amsterdam and the entire Dutch highway network. Achieved a 44 travel time prediction improvement for the Amsterdam network. Encapsulate the entire Dutch highway network dynamics with a 93 prediction accuracy. |
S0968090X20307531 | In this paper a novel transport planning model system is formulated built on the concepts of network multi modality integrity and instant calibration . In the proposed formulation activity travel pattern choice elements including the choices of activity activity sequence mode departure time and parking location are all unified into a time dependent ATPs generator . The proposed model accounts for the dynamicity of the network including time of day and congestion effects in a joint structure for transport supply and demand . Moreover the proposed TPMS explicitly formulates an operating capacitated public transport system . To allow visiting locations multiple times and to alleviate the complexity of the proposed model a novel multi visit vehicle routing problem is proposed which does not enumerate the node and link visits . In order to calibrate the model based on the major travel attributes of the travel survey data a set of splitting ratios are introduced to distribute trips on the network . The model uses the splitting ratios to integrate the ATPs generator and the traffic assignment model in a unified TPMS structure . The effectiveness of the proposed structure is demonstrated through numerical examples provided . | An innovative platform for jointly modelling supply and demand. A large scale supernetwork with multimodality. An activity travel pattern ATP choice model accounting for parking location. |
S0968090X20307543 | The goal of this research study is to model user preferences and response times jointly in the context of Mobility on Demand services under different MOD operator pricing schemes information frames and pressure levels . MOD operators information provision delay and vehicle allocation strategies influence users preferences and RTs which in turn affect which operational and information provision strategies are optimal for MOD operators . Evidence shows that preferences and RTs are sensitive to precedent decisions information frames risk and time pressure . These dynamic | Considers the impact of information update framing effect dynamic decisions and time pressure in ordering a mobility on demand service. Jointly utilizes multi attribute prospect theory diffusion model decision field theory and random utility model. Demonstrates the importance of modeling and analyzing a decision of ordering on demand mobility service as a sequence of sub decisions. The outputs of the behavioral model are the probability of choosing each option and the corresponding response time distribution. |
S0968090X20307579 | Massive and passive Automatic Vehicle Identification data provides samples of whereabouts and movements of vehicles which is a potential source of information for route choice behavior modeling . However the AVI observations are too sparse to infer the specific chosen route and OD pair which discourages its application on route choice model estimation . To tackle this issue this paper develops a semi supervised learning method that can train the route choice model with sparse AVI observations . First of all the likelihood function in Maximum Likelihood Estimation procedure was derived by decomposing the AVI trace into observation pairs . Combined with high resolution GPS observations the measurement equation and OD inference model were then defined to deal with the sparsity problem of AVI observations . At the same time the Mixed Logit model was introduced to capture the correlation and heterogeneity across the choice behavior between different observation pairs . Finally the relationship between route choice model and the likelihood function was established and the unknown parameters in route choice model can be estimated by seeking a maximum to the log likelihood function . Empirical studies were conducted with field testing data in this paper . The estimated results show that the proposed semi supervised method improved the identification accuracy of route choice model significantly without sacrificing interpretability . The evaluation of the computational efficiency presented the potential of the semi supervised method to learn route choice behavior for a large size sample set . The sensitivity analysis was also performed to illustrate how robust the proposed method is . This is the first research that attempts to apply AVI data on route choice model and it endows the high penetration AVI data with great practical value for modeling the route choice behavior of city wide samples over a long period . | Developed a semi supervised framework to learn route choice behavior from AVI data. Improved the identification accuracy significantly without sacrificing the interpretability. Presented potential to build route choice model for massive individuals for a long period. |
S0968090X20307609 | In this paper an optimization based speed control method is proposed to alleviate the adverse effects of bus bunching . This method specifically focuses on one way line transit corridors with curbside stops and high frequency buses . In such public transit corridors holding buses at stops may not be suitable for implementation . Instead of holding we choose to control bus cruising speeds between stops . The relationship between holding and speed control is discussed . A conventional holding model | A bus cruising speed control method is designed for high frequency buses. We compare our proposed method with the conventional holding method via simulation. The proposed method can reduce both passenger as well as bus waiting delays effectively. Four driver friendly implementation strategies are further proposed discussed and evaluated. |
S0968090X20307610 | Multi vehicle routing problem with soft time windows is an indispensable constituent in urban logistics distribution systems . Over the past decade numerous methods for MVRPSTW have been proposed but most are based on heuristic rules that require a large amount of computation time . With the current rapid increase of logistics demands traditional methods incur the dilemma between computational efficiency and solution quality . To efficiently solve the problem we propose a novel reinforcement learning algorithm called the Multi Agent Attention Model that can solve routing problem instantly benefit from lengthy offline training . Specifically the vehicle routing problem is regarded as a vehicle tour generation process and an encoder decoder framework with attention layers is proposed to generate tours of multiple vehicles iteratively . Furthermore a multi agent reinforcement learning method with an unsupervised auxiliary network is developed for the model training . By evaluated on four synthetic networks with different scales the results demonstrate that the proposed method consistently outperforms Google OR Tools and traditional methods with little computation time . In addition we validate the robustness of the well trained model by varying the number of customers and the capacities of vehicles . | A novel reinforcement learning algorithm that can solve vehicle routing problem with soft time window. An encoder decoder framework with attention layers to generate tours of multiple vehicles iteratively. Proposed method outperforms benchmark models and Google OR Tools in most scenarios with much little computation time. The pre trained model can be deployed instantly without further training for new problems. |
S0968090X20307701 | With the rapid development of urbanization and modernization it is increasingly crucial to sense network wide traffic . Network wide traffic volume information is of great benefit for traffic planning government management and vehicle emissions control . However it is difficult to install detectors on every intersection due to the expensive deployment and maintenance costs and the insufficient sensor coverage across the network limits the direct availability of network wide traffic flow information . Whereas crowdsourcing floating car data with a high coverage rate are currently available which creates an opportunity to address this problem . In this paper we propose a novel methodology to estimate network wide traffic flow which incorporates flow records and crowdsourcing floating car data into a geometric matrix completion model . Furthermore a spatial smoothing index based on the divergence is developed to measure the difficulty of volume estimation for each road segment . We conduct extensive experiments on both real world and synthetic datasets . The results demonstrate that our approach consistently outperforms other benchmark models and that the proposed index is highly correlated to estimation accuracy . | A spatiotemporal matrix completion model for network wide traffic flow estimation. The proposed model is formulated as a quadratic programming and solved by ADMM. A spatial smoothing index based on the divergence is developed to measure the difficulty of estimation. Both real world and synthetic datasets to evaluate algorithm performances and acquire insights. |
S0968090X20307713 | Lane changing manoeuvre is one of the risky manoeuvres performed by drivers either to reach the planned destination or to achieve better driving conditions . Essentially both lane changing types require the driver to acquire surrounding traffic information for efficient and safe lane changing decisions . However this does not discount the fact that both these lane changings are fundamentally different from each other as the urgency of lane changing is much higher during MLC compared to DLC . Real time driving aids in a connected environment promise to assist during the lane changing decision making process but the differential effectiveness of real time driving aids in a connected environment for these two lane changing types remains unexplored due to the novelty of a connected environment and the consequent scarcity of data . To fill this research gap this study collected lane changing data from 78 participants who performed MLC and DLC in the CARRS Q Advanced Driving Simulator . Participants were asked to drive in three randomised driving conditions baseline condition real time driving aids in a connected environment with perfect communication and delayed driving aids in a connected environment . While surrogate measures of safety are analysed and compared using descriptive statistics a hybrid framework of data mining and classical statistical modelling is employed to examine the usefulness of the real time driving aids in a connected environment for two lane changing types . We find that the crash risk associated with MLC is significantly reduced in the driving conditions providing driving aids compared to that of DLC . Results also reveal that the probability of engaging in a hard braking event decreases for both the lane changing types in the presence of real time driving aids in the connected environment driving conditions but a higher decrease in magnitude is found for MLC . Age and gender related differential impact have been observed where young and male drivers have a higher possibility of engaging in a hard braking event when driving without driving aids but the presence of real time driving aids reduces such risk . This study concludes that the usefulness of the real time driving aids in a connected environment is a function of the urgency of a task which is evidently higher during MLC thus providing the maximum advantage during MLC . | Investigation of effectiveness of driving aids during lane changing manoeuvres. Observations of mandatory and discretionary lane changing in advanced driving simulator. Main benefit from driving aids during mandatory lane changing. Impact of communication impairment is more pronounced during mandatory lane changing. |
S0968090X20307725 | Among several crucial objectives of the air transportation system minimization of fuel consumption has a profound impact on the economic viability of airline companies and their effect on the environment . Given that many large airports around the world are located in the heart of residential areas such as Chicagos OHare New Yorks JFK and Montreals Pierre Elliott Trudeau the Greenhouse Gas Emissions released by aircraft flying through such urban airports directly impacts the health of nearby residents . In this paper we propose a hybrid taxiing solution to reduce the airports impact on GGE where part of the taxiing operations is handled by tow trucks powered by renewable energy while some other aircraft continue using their engines to complete taxiing . The main contribution of the work presented in this paper is the inclusion of collision of conflict avoidance in the formulation of taxiing operations planning with an objective to minimize fuel consumption and to maximize the desired service quality . The conflict free taxing operations planning model is tested on Montreals Pierre Elliott Trudeau airport . Furthermore the detailed economic analysis on the adoption of electric powered tow trucks is provided . | Formulation of airport taxiing operations in consideration with collision and conflict avoidance. Electric powered towing vehicle consideration for taxiing. Economic analysis of aircraft towing option between gates and runways. Case study on Montreals Pierre Elliott Trudeau airport. |
S0968090X20307737 | Bus operations on arterials are often hindered by traffic signals and car queues . Transit signal priority strategies can be used to improve bus operations on arterials . Analytically quantifying the impacts of TSP in mixed traffic where cars and buses share lanes is challenging since car queues can slow down buses while slow moving buses can create bottlenecks for cars . Furthermore computational costs increase significantly when considering an arterial with multiple intersections . To tackle these challenges this paper first develops a dynamic programming framework to model and evaluate TSP along an arterial . Next the algorithm is utilized to determine the changes to car and bus delays as a result of TSP implementation along an arterial and the sensitivity of the algorithm to the signal timing plan bus stop locations and dwell durations and the bus headway is evaluated . Next a bi level optimization framework is proposed to determine the optimal location of TSP implementation along arterials . Finally the results of integrating TSP with dedicated bus lanes is evaluated . The results suggest that the benefits of TSP largely depend on the signal setting and bus stop location and that as the bus headway decreases the marginal benefit of providing TSP also decreases . Additionally the results suggest that the specific intersection at which TSP is implemented can play a large role on its operational impacts . Finally it is found that in some scenarios the benefits of implementing TSP alone can be larger than implementing dedicated bus lanes alone . | Analyze transit signal priority considering buses as moving bottlenecks. Develop a dynamic programming methodology to analyze transit signal priority along an arterial. Understand impacts of signal settings on arterial level TSP implementation. Determine optimal locations for TSP implementation on an arterial. Compare delay benefits of dedicated bus lanes to TSP on an arterial. |
S0968090X20307749 | Cooperative Adaptive Cruise Control has been regarded as the most promising technology that can be carried out in field earliest under partially connected and automated environment and is one of the few Connected and Automated Vehicle applications closest to its final shape . Therefore validation of CACC running in real traffic is in urgent need . To support the validation simulation plays a key role . This paper proposes a next generation simulation platform for CACC evaluation and validation . It is able to not only validate the performance of a CACC platoon by itself but also evaluate its performance when being released into the traffic . In addition it can also quantify the impact of CACC vehicles on transportation systems . The proposed platform is generic in terms of CACC control system background traffic condition road geometry and traffic control scheme . Furthermore it is capable of capturing the dynamics of platoon formation and disengagement when CACC equipped vehicles are mixed up with human driven vehicles . The proposed platform is validated by comparing against actual field data and previously published theoretical studies . The results confirm the credibility of the proposed platform in terms of i CACC control system embedded ii CAV and Human driven Vehicle mixed traffic simulation iii managed lane simulation . It is also revealed that current CACC technology without upgrade may be a safety hazard and permitting CACC only on a dedicated CACC lane might be a good first step for CACC commercialization at this moment . | Enabling evaluation of both CACC control system performance and its impact on the transportation system. Fast simulation speed for potential real time applications and large scale simulation. Taking human machine task switching into account. Ensuring the accuracy by incorporating a lower level controller with a credible VDM. Compatibility with any CACC controller and VDM. |
S0968090X20307750 | This paper proposes to enhance the current tromboning paradigm with a four dimensional trajectory negotiation and synchronization process with the aim to maximise the number of neutral Continuous descent operations achieved by the arriving traffic in terminal maneuvering areas . An optimal control problem has been formulated and solved in order to generate a set of candidate CDO trajectories per aircraft while a mixed integer linear programming model has been built in order to optimally assign routes of the arrival procedure and required times of arrival to the arriving traffic when still in cruise . The assessment has been performed for Frankfurt am Main airport by using arrival traffic gathered from historical data . Results show that after assigning an RTA and a route to every arriving aircraft it is possible to maximize the number of aircraft performing CDOs while ensuring a safe time separation throughout the arrival procedure . For low traffic scenarios the totality of traffic can be successfully scheduled while for high traffic scenarios this is not the case and not all aircraft can be scheduled if neutral CDOs are flown . However by assuming different arbitrarily defined arrival times to the TMA or by considering more additional shortcuts in the trombone procedure it is possible to increase the number of aircraft scheduled . Besides improving current operations in the short mid term the methodology presented in this paper could become a technical enabler towards a fully deployed trajectory based operations environment . | A technical enabler towards a fully deployed trajectory based operations environment. Arrival traffic is sequenced with 4D closed loop instructions in a tromboning. The amount of CDOs is maximized and delay is minimized. TMA entry time distribution greatly affects the number of neutral CDOs that can be flown. |
S0968090X20307774 | Congestion recognition is the prerequisite for traffic control and management vehicle routing and many other applications in intelligent transportation systems . Different types of roads with traffic facilities provide multi source heterogeneous field traffic data which contain the fundamental information and distinct features for congestion recognition . To exploit these traffic big data in this paper we propose a machine learning based framework to tackle the congestion recognition problem . It can be divided in two parts a digraph based representation for hybrid urban traffic network and a Dirgraph Convolutional Neural Network based learning model . At first the representation incorporates the fundamental traffic variables with the correlation of different traffic flows and partially decouples the global network topology from local traffic information . And then to proceed with digraph based samples a new type of graph feature extraction method is introduced and the graph Fourier transform is defined accordingly . This distinguishes the proposed model from the conventional graph convolutional networks . Comprehensive experiments are conducted based on real traffic data . The results demonstrate the advantages of the proposed framework over the existing congestion recognition methods . | We provide a novel digraph based representation of hybrid urban traffic networks. We introduce Graph Fourier Transform towards the digraph convolution method. We construct sub graphs through spanning trees for congestion recognition. Experimental results show that the model achieves the state of the art performance. |
S0968090X20307816 | With the increasing activities of unmanned aircraft near airports severe challenges have emerged regarding airport safety management . This paper presents a brand new data driven based approach to accurately design the geofencing for UAs around an airport focusing on midair collision risk between commercial flights and small UAs which is considered as the most important hazard . In premise prevalent trajectory extraction from real flight tracks is realized based on an advanced and general model taking the advantage of describing turning legs which is more popular in terminal area . As a key solution a Gauss Laplace composite distribution is provided for rigorous estimation of flight track distribution in line with the extracted prevalent trajectory . Based on those airport geofencing is proposed consisting of an inner critical area and an outer buffer area . This approach can be adaptive for different traffic patterns of an airport . The buffer area is an extension range to help the execution of some defense measures . Results of an empirical study for setting up geofencing for small UAs around Chongqing Jiangbei International Airport show the superiority of the proposed approach which indicates that it can provide practical application especially varying from different target level of safety . | Proposed approach shows great advantages in terms of its accuracy with adaptive and executive functions. Compared with current methods which are too simple and rough we design a more accurate airport geofencing with an inner critical area and an outer buffer area by estimation of flight track distribution in line with extracted prevalent trajectory. This geofencing is adaptive for different traffic patterns. Furthermore the buffer area is deliberately designed as an extension range to help flexible execution of some defense measures. An advanced prevalent trajectory model APTM is provided to determine the prevalent trajectory based on real flight tracks. The APTM is different from existing prevalent trajectory extraction methods such as the clustering methods especially in the point that it can match the real tracks better when dealing with turning situations. This feature is very important considering lots of turning requirements in terminal flights and its the foundation of the operation compliance of our method. To decrease lateral estimation errors between the prevalent trajectory and real flight tracks we utilize a Gaussian Laplace composite distribution instead of solo Gaussian distribution. We show that the composite distribution is valid in estimating rigorous flight track distribution. |
S0968090X2030783X | This paper presents a study in examining the desired savings in travel time per trip and travel cost per month that would motivate people to switch to ride sourcing options . Simultaneous regression models with latent constructs were employed to estimate the expected time and cost savings . The presence of latent constructs accounts for the endogeneity in personal attitudes while the simultaneity allows the analyst to evaluate the potential correlation between the two decisions . Various socioeconomic and demographic variables and personal attitudes were explored in the model to investigate their potential influence on the willingness to adopt ride sourcing . Analysis based on the survey data indicated an average desired time saving of 20min per trip and an average desired cost saving of 116 per month to switch to on demand services . Accordingly individuals younger than 25years old between 55 and 59 those with lower education levels Asians low income individuals people with previous ride sourcing experience and those who did not favor private car ownership showed lower expectations in view of both travel time and travel cost savings and therefore were more willing to adopt on demand services . On the contrary people aged 3039years old highly auto dependent individuals self employed people who hardly trust strangers and those who value private ownership advantages such as privacy and convenience would demand higher savings to convince them to adopt ride sourcing . This study provides an approach to evaluating the propensity of ride sourcing usage in view of the desired travel time and cost savings . A better understanding on the magnitude of time and cost savings needed to motivate the public to switch to ride sourcing options would provide policy makers with valuable information in designing effective and efficient policies and strategies in promoting shared mobility options . | A structural equation model was developed to explore ridesourcing propensity. Desired savings in trip travel time and monthly mobility cost were analyzed. Education income age race and prior experience showed significant impacts. Attitudes toward privacy convenience trust and cost also played significant roles. |
S0973082618309153 | Over the years a significant need has been established to develop stove testing protocols that reflect the performance of fuel stove combinations in the field better . This is particularly true for alcohol based liquid fuels widely seen as a future replacement for kerosene fuels in the informal and less affluent communities of South Africa . This paper aimed to evaluate three liquid fuelled stoves using cooking sequences derived from a typical township in Johannesburg South Africa based on a contextual testing approach which is a revised in situ testing protocol based on the Uncontrolled Cooking Test . The devices were evaluated and rated based on their intended contexts of use in South Africa using the new contextual testing protocol which was combined with the old Heterogeneous Stove Testing Protocol . Overall results showed that there are no significant differences | Evaluation of three methanol stoves using cooking sequences derived from Setswetla Johannesburg South Africa. Presentation of a contextual testing approach. No significant differences between averaged cooking sequences and the uncontrolled cooking task. Information obtained in the field on actual use conditions may be valuable to stove developers and disseminators. Laboratory test sequence with the same power levels for cooking food produced nearly the same results as a UCT. |
S0973082618316429 | This paper focuses on low energy interventions in the design and use of houses from a socio technical perspective . It explores the links between housing and household practices for sustainability transitions in middle class housing in Lahore Pakistan . Using two case study houses as examples of variation in design in addition to semi structured interviews with housing practitioners the paper investigates the transitions needed in housing practices that through interventions in house design can lead to less energy intensive household practice arrangements . It uses a practice based intervention framework to explore how housing and household practices can be recrafted substituted and changes made to how they interlock for improved sustainability . Good housing practices such as integration of more flexible performance based byelaws to meet minimum standards better knowledge and skills of practitioners good communication between stakeholders and the availability of low carbon material supply chains can lead to good household practices such as changed meanings of comfort more outdoor based activities and collective practice arrangements . The paper thus highlights inadequacies of existing economically driven techno determinist efficiency models to meet required levels of housing energy demand . The practice approach makes the connections between good and bad housing and household practices visible and demonstrates their significance in identifying key areas of sustainability interventions . | Housing practices influence household practices mediated through the house design. Good housing design practices can lead to good household use practices. Recrafting substituting changing interlinks in housing and household practices. A systems approach is required to make housing practices less energy intensive. Technological and socio cultural innovation should drive sustainability transitions. |
S0973082619302534 | This paper evaluates the economic environmental social and political impacts of a wider diffusion of photovoltaic distributed generation and energy efficiency measures on the markets of electric power distribution utilities in Brazil . The impacts are calculated for three substantially different power distribution utilities which are representative of the types of utilities found in the country . Key indicators were selected to reflect the main interests of the following stakeholders power distribution utilities the government and low voltage consumers . The results show that the most important issues that should be addressed concerning a large diffusion of EE measures are tax collection and tariff rises . The simulations show that tariff rises can be hampered by EE actions targeted to specific locations and specific actions . The most important impact of PVDG diffusion is on tariff rises considering the current regulatory framework in the country . On the other hand the net jobs creations of EE measures and particularly PVDG are significant and the cost of job creation in relation to fiscal waiver by investment on PVDG is cost effective . The GHG emissions avoided by the higher levels of PVDG and EE in 2040 simulated in this study showed to be significant for both EE measures and PVDG . | Description of Key indicators selected to reflect the main interests of utilities the government and consumers. Quantify impacts on indicators. Analysis and discussion of impacts on indicators. |
S0973082619305745 | This paper aims to present insights about distributed photovoltaic generation technology diffusion in the household market . A quantitative approach using the Bass model to project distributed PV systems adoption is chosen to base and conduct the analysis . Since distributed PV in Brazil still presents a very small market penetration historical data is still insufficient to obtain robust estimates . Therefore parameters from PV markets of other countries and parameters from the solar water heaters market in Brazil are used in the analysis . The latter approach is carefully justified . A comparative analysis of distributed PV and SWH market features indicates that SWH diffusion parameters lead to a better representation of innovators behavior for residential PV adoption in Brazil than the parameters borrowed from other countries which are used by the official projections performed by the Brazilian regulator of the electricity sector . Moreover we propose a different approach for estimating the final potential market . We discuss the limitations of the official projections since results indicate that official projections overestimated the diffusion of residential PV market in the early years . Finally it is suggested that inaccurate signals could be given to stakeholders . | Insights about residential PV market diffusion in Brazil based on the Bass model. PV diffusion in an incipient market using Bass model parameters from SWH market. Diffusion of PV based on SWH parameters presents better results than official projections. Estimation of final potential market for distributed PV and solar water heaters markets. Brazilian SWH market diffusion using the Bass Model with dynamic potential market. |
S0973082619305769 | Wet processing is the most energy intensive subsector in the textile industry . The complex nature of specific energy consumption warrants a closer look at the independent parameters impacting the SEC . Energy audits were conducted in twelve knit fabric processing plants processing fabric quality of 160180g per square meter in South Asian countries to normalise independent parameters like fabric characteristics geographic location and production processes . Energy consumption profiles SEC independent parameters impacting SEC resource conservation measures and their predicted impact on SEC were evaluated . Also the values for annual baseline Greenhouse Gas emissions and predicted emission reduction were calculated . The most energy intensive fabric dyeing section consumed an average 32 of plant s electrical energy and 69 of the plant s steam . The baseline SEC of 3984GJ t was predicted to be reduced to 2958GJ t by implementing the RCMs . The baseline SECs had high correlation with values for plant capacity utilisation and heat rate for power generation . Priorities were established on the different areas for resource conservation for different plant configurations . The specific emission was predicted to reduce from 2.1 4.3 tCO | Energy diagnosis of twelve knit fabric based wet processing plants were studied. Fabric dyeing is the most energy intensive section 69 of steam consumption. Developed framework for quantifying replicable resource conservation measures RCM . Specific energy consumption SEC can be reduced by about 18 40 . Benchmarking plant performance should factor these replicable RCMs along with SEC. |
S097308261930585X | The focus of this research is the potential of biomethane in Britain s gas grid . It examines its relative ability to address Britain s sustainability and energy security challenges from an economic perspective . Such research is important because UK is wedded to gas for heat production and power generation and is increasingly dependent on imported gas in line with shrinking domestic production and uncertain future trading relationships . Also dependency on natural gas threatens Britain achieving its legally binding carbon budgets . The study included a thorough literature review primary research to finally uncover the views of key UK market participants plus analytical modelling . The findings reveal that the market is cautiously optimistic despite reservations regarding feedstock availability and the impending cessation of subsidy approvals . Investors are in greater need of long term certainty however and the challenge of decarbonising heat and heavy duty transport warrants this . Retail price premiums are polarised but in line with wholesale costs relatively high compared to electricity . The key recommendation is for the policymakers to follow precedents in renewable electricity and liquid biofuels by mandating that energy suppliers owners of heavy duty road fleets and occupiers of new buildings purchase biomethane . In tandem feedstock and grid entry restrictions must be tackled creatively . | Dependency on natural gas threatens Britain achieving its carbon budgets. Biomethane is a solution for sustainable and clean gas supply for the UK. Cautiously optimistic market in the UK on the future of biomethane in the energy mix. Polarised retail price premiums for green gas relatively high compared to electricity. Recommendation UK policymakers to follow renewable electricity precedents |
S0973082619306271 | This paper presents the results of an analysis that explores how Typical Meteorological Year informed power system models perform when exposed to atypical variability . A simplified power system planning model is tested for two case studies in Guinea Bissau and Turkey . A TMY proxy is compared against 24 year timeseries datasets containing hourly resolution solar PV and wind capacity factor data . Results show that unforeseen shortages in VRE generation and additional expenses are approximately 36GWh and 10 million USD for Guinea Bissau and 92GWh and 232 000 million TL for Turkey . Moreover Turkey faces unmet demand of up to 50TWh . For Turkey unmet demand is penalized at 5000 TL MWh explaining the high cost increase . The underperformance of the TMY based simulated system also is responsible for 45.77 million kg of unforeseen CO | TMY based power systems underperform when exposed to atypical variability leading to unforeseen costs in both case studies. In the case of Turkey the TMY based power system cannot meet demand when exposed to full variability. In the case of Guinea Bissau the underperformance of the TMY based power system leads to additional CO. emissions. |
S0973082619306647 | Mini grids have been widely developed for rural electrification purposes in Kenya predominantly as systems combining photovoltaic modules a diesel generator and battery capacity . wind turbines have been largely neglected in such setups and are basically non existent in Kenyan mini grids despite potential complementarity with PV due to different temporal production profiles of PV and wind power . | The complementarity of solar and wind resources is explored in a mini grid setting. Energy system analysis backtesting the feasibility of hybrid PV wind solutions for a Kenyan case. Assessment of barriers to the diffusion of hybrid PV wind mini grids in Kenya. Hybrid PV wind solutions show techno economic potential to reduce LCOE. Substantial systemic technical and economic barriers hinder diffusion. |
S0973082619306684 | Solar PV technology is the most promising renewable energy technology and is able to fulfill the electricity demand of the whole world even after conventional sources are completely finished . The prediction of actual electricity output from PV plants under actual outdoor conditions is tough . Performance evaluation of installed PV plants is helpful in designing and prediction of the performance of other upcoming PV plants more precisely . IEC 61724 gives the standards by which the performance of a PV plant can be judged . At present several research works based on performance evaluation of PV plants carried out in distinct locations across the world are reported in the literature . It is important to review results from various case studies on the basis of the IEC 61724 standard . In this paper the various case is reviewed on the basis of their location commissioning year capacity used technology and their performance . This will be helpful to design a PV plant knowing previous commissioned plant performance . From the review it has been found that PV plants are installed in most of the countries in the world and they are demonstrating satisfactory results . It has also been found that PV module material and panel tilt angle is very crucial for designing a PV Plant . | A review of the performance of various the PV plants has been presented. The comparison of PV plants has been done based on IEC 61724 Standard. Various plant outcomes have been surmised into a single table. Various important aspects of the PV plant have been filtered out. |
S0973082619307471 | Household air pollution continues to be a global public health burden as 2.8 billion people still rely on open fires or inefficient cookstoves . The majority of morbidity and mortality are related to inhalation of fine particulate matter and many initiatives have focused on reducing PM emission and resulting exposure . For this reason targets for emission rates to meet air quality guidelines have been set by the World Health Organization and International Organization for Standardization . These targets are based on a single zone box model that assumes released particles are distributed uniformly throughout the kitchen . However particulate matter is known to stratify vertically and therefore personal exposure to the cook and others in the kitchen may not be predicted accurately by a single zone model . Therefore this study compares empirical measurements of PM stratification to box model predictions to determine if the single zone model is appropriate for predicting PM exposure at the expected breathing zone of the inhabitants . A test kitchen with a fixed ventilation rate and dimensions common to kitchens in rural areas was built and fitted with thirty HAPEx PM Sensors were evenly distributed at 4 different heights within the kitchen . Seventy modified water boiling tests were performed with a common rocket stove operating at known firepower and emissions rates in two testing phases at 10 15 and 20 air exchanges per hour . Results showed stratification was less pronounced with increasing ventilation and with decreasing firepower . Measured concentrations at 15 ACH were compared to the predicted value from the single zone model showing equilibrium at a height of approximately 1.6m . The box model over predicted concentration at heights lower than this including a 2363 excess at the 1.3m high breathing zone of a typical standing cook . This implies that the current emission rate targets may be overly conservative under these conditions precluding use of some types of biomass cookstoves that may actually be able to meet air quality guidelines . Future modeling and empirical studies should be conducted to understand under what conditions the use of the box model is appropriate and when it should be modified for more accurate incorporation of the effects of stratification . | A test kitchen with standardized dimensions and adjustable ventilation was built. PM concentration was monitored throughout the room in 70 tests at 3 air exchange rates. Stratification was significant with decreasing ventilation. The single zone box model over predicted concentration in the breathing zone. Future research may be needed to improve the WHO emission rates targets. |
S097308261930777X | Energy justice building on foundations within both the field of environmental justice and wider justice scholarship has grown rapidly as a research field over recent years . However the dominant energy justice theoretical frameworks and many of the field s core case studies originate from work in developed countries with energy justice research only recently spreading to new areas of the world . This paper thus systematically reviews the current state of developing economy and economy in transition literature in the energy justice field . In doing this we analyse the methods energy types and locations explored thus far unearthing key gaps as well as the multitude of justice led theoretical frameworks used . We also identify core themes illuminated by energy justice research in the developing world including decentralisation access and sustainability exposing institutional instability and corruption acknowledging marginalised communities and gender inequalities while extracting key policy implications . Vital questions are raised for the continued advancement of energy justice research into new contexts and thus its conceptual evolution . Our review highlights the potential for energy justice led attention to expand current institutional contextual and empirical scope in specific ways including greater attention to the poorest global regions and certain energy technologies including nuclear and CCS . We suggest four ways in which future theoretical developments of the field might take place greater attention to spatial analyses of neglected regions expanding the field to further include non western philosophical traditions more work on applying tenets frameworks and principles specific to energy justice and systems approaches to developed developing country relations with an emphasis on how they relate to low carbon transitions . Thus while we explore past and present applications of energy justice in developing world contexts we also offer guidance on the ways in which it could be applied in the future alongside encouraging dialogue between different justice fields . | First systematic review of energy justice studies in developing world contexts. Research emphasis on renewables qualitative methods and specific regions noted. Three tenets approach dominates environmental social climate justice also central. Energy decentralisation advocated to increase access and or enhance sustainability. Policy emphasis on increasing participation little on reducing power of elites. |
S0973082619308361 | In this paper we have examined scaling reliable electricity access in India from two perspectives . First given past policies we examine the ability of mini grids to achieve profitability at the unit level as well as potential for scaling . We find that many mini grid developers have shown profitable unit economics and are getting ready to scale however they face increased challenges given India s success with 100 electrification . Second given the experience gained by mini grid operators we explore collaborative business models that would allow for win win situations going forward for both distribution utilities and private operators . We use a modification of the existing distribution franchisee model to allow the mini grids operations to manage not only metering and billing but also operation and maintenance as well as generation . We show that it is possible to create business models that not only are appealing from a financial perspective i.e . in not only improving distribution utility margins but also in meeting private operator criteria of 12 internal rate of return but also meet multiple policy objectives such as provision of 24 hour electricity reliably and meeting renewable power obligations . However we also show that the eventual success of these models would critically depend on the distribution utilities and mini grid operators agreeing on elements of these business models in particular equitable sharing of roles and responsibilities around generation distribution operations and maintenance metering and billing as well as financial value . | We examine scaling reliable electricity access in India using a public private partnership model. It is possible to meet financial criteria for investment but also multiple policy objectives. Eventual success depends on stakeholders agreeing on elements of business models |
S0973082619309160 | The objective of this study was to redesign and refinance a rural microgrid on the small island of Koh Jik in Thailand . A series of microgrid scenarios were modeled and evaluated using HOMER software with the aim of providing techno economic insights on the sustainable redesign of a rural and resilient system . Existing assets were analyzed and integrated into a new system design whereby the addition of extra PV panels and replacement of current lead acid battery by a lithium ion battery increased the renewable fraction of electricity generation from an estimated 55 83 . The system was optimized holistically to provide the lowest cost of electricity combined with the highest renewable fraction in order to attract private investment for such electricity access projects . A LCOE as low as 0.220 kWh was obtained for Li ion compared to 0.307 kWh for the LA basis translating into a project payback as low as 6.3 years . All the modeling economics were cross checked with a cash flow statement model using the island s financial books and current price of electricity and showed that the HOMER modeling results were within a range never exceeding 4 . Comparison of scenarios clearly outlined the advantages of Li ion microgrids over LA in all aspects except capital expenditure explaining why as of today rural electrification projects still commission less sustainable LA systems due to initial capital constraints . While the battery CAPEX price per kWh storage was found still considerably lower for LA in order to reach high renewable fractions larger battery banks are required thus driving project costs higher and closer to Li ion prices . Positive lessons learned from Koh Jik case study can increase the confidence of both investors and governments while accelerating such initiatives in neighboring Southeast Asian countries or other territories around the world struggling with island electrification . | Size of storage capacity directly dictates the renewable fraction of systems. Very high Li ion CAPEX hinders the deployment of rural electrification projects. HOMER model economics and financial model cash flows results within 4 deviation. Payback period as low as 6.3 years was obtained for a Li Ion battery system. |
S0973082619309913 | To counteract the threat of global warming many nations have resorted to increasing their use of renewable energy sources wind farms being among the most popular . The greatest obstacle when it comes to the acceptance of wind farms is their visual impact . Recently tourism has become Iceland s largest export sector the country s natural landscape being the main attraction for visitors . This paper attempts to compare the perception of residents and tourists towards wind energy production in general and towards Iceland s first proposed wind farm to be located at the edge of the country s uninhabited interior Central Highlands . The study is based on a questionnaire survey conducted among residents living adjacent to the proposed wind farm and among tourists travelling through the proposed area . The results indicate that residents are more positive than tourists towards wind turbines and consider them less intrusive in the landscape . Hence the location of Iceland s first wind farm at the main gateway into the country s Central Highlands is problematic and likely to disturb the experience of tourists passing through the area . Despite the wealth of wind in Iceland it might be challenging to utilize it for energy production due to the importance of nature based tourism for the economy . If Iceland becomes a physical exporter of renewable energy it may be expected that more pressure will be set on the construction of wind farms . Thereby nature based tourism and wind energy would be in direct competition over land use . | Wind turbines reduce the naturalness of a landscape and the quality of wilderness. Residents and tourists consider landscape without power plant infrastructure more beautiful. Tolerance level towards landscape change is higher among residents than tourists. Economic reasons are likely to influence residents opinion on wind energy production. A wind farm in the Southern Highlands of Iceland poses a threat to the tourism industry. |
S0973082619310853 | The importance of the charcoal sector is growing rapidly in Sub Saharan Africa . In addition to providing an affordable energy source for residents in the continent s growing urban centers the charcoal value chain offers a critical income source for millions of people . Despite recent studies suggesting that women are taking on an increasing role in charcoal value chains data and analysis on the role of women and the influence of gendered power relations in the often male coded charcoal value chain have remained limited . This literature review interrogates the gender dynamics of participation and benefits across charcoal value chains in Sub Saharan Africa . We find significant support for women s participation throughout value chains thereby contrasting conventional views of charcoal as a male activity . However while dynamics change between different contexts women s participation tends to be significantly higher in retail while women tend to constitute a minority in other parts of the value chain often joining the sector in the absence of alternative livelihood opportunities . The review also finds that gender differences exist across various nodes in terms of the scope nature and outcomes of participation . While significant regional differences exist our study finds that participation and outcomes tend to generally be influenced by gender differences and inequalities in 1 access to and control over productive resources and income 2 social and political capital and 3 gender roles and responsibilities . Importantly other axes of social differentiation such as generation marital status wealth and social class often intersect with gender relations in influencing outcomes . In addition to structuring the extent nature and outcomes of women and men s participation we argue that gender roles and relations may significantly influence the efficiency and sustainability of the charcoal value chain . Based on our findings we call for placing gender at the core rather than periphery of charcoal value chain studies and propose a conceptual framework for incorporating gender analysis in future value chain studies in the charcoal sector . | Recent studies suggest that women are taking on an increasing role in charcoal value chains. However data on the role of women and gender relations in the charcoal value chain is limited. This article reviews and assesses evidence on the gender dynamics in charcoal value chains across Sub Saharan Africa. We find that gender differences and inequalities in the extent nature and outcomes of participation exist. Such differences may influence the efficiency and sustainability of charcoal value chains. We propose a conceptual framework for incorporating gender analysis in future value chain studies in the charcoal sector. |
S0973082619311792 | This paper proposes a novel methodology for the detection of partial shading conditions in photovoltaic arrays based on the experience gained in the preliminary step of the detection algorithm . In the first stage of the problem the periodic partial shading detection problem is solved to detect the periodic partial shading condition and to determine the optimal number of executing point of MPPT algorithm during PSC . The second stage of the PSD problem solves the maximum power point tracking problem to extract the maximum power from PV array at the executing point . The PSD problem is solved using the sine cosine algorithm and to determine the global maximum operating point under various partial shading conditions the improved sine cosine algorithm is proposed . The proposed method is guaranteed to find periodic shade and the global maximum operating point avoiding the local operating point obstacle . Using MATLAB the algorithm is implemented and tested in a simulation model . An experimental 2kW PV system is developed to validate the operating point of the PV system under various partial shading patterns . The results demonstrate that the proposed algorithm outperforms the genetic algorithm and particle swarm optimization based partial shading detection problem . | Paper proposes a novel methodology for detection and assessment of partial shading conditions in PV arrays. In Stage I periodic partial shading detection PSD problem is proposed to solve using the sine cosine algorithm SCA . The PSD problem is to detect the periodic partial shading condition and optimize the executing point of MPPT algorithm. In Stage II the PSD problem solves the MPPT problem to extract the maximum power at the executing point. The simulation and experimental results demonstrate that the proposed algorithm outperforms the other methods. |
S0973082619311950 | Electrification policies are crucial to improve the welfare of rural populations worldwide . In this context auctions for the deployment of stand alone solar home systems are an appropriate alternative to facilitate access to electricity in rural areas . The aim of this paper is to analyze the design elements and functioning of the SASHS auction in Peru in order to derive lessons for the effective and efficient design of those auctions . Based on an analytical framework developed elsewhere this article draws on official documents and data secondary material and interviews with stakeholders . Our results show that some design elements are particularly suitable in this regard . In contrast to renewable electricity auctions in general for which the volume auctioned is usually set as capacity or generation the volume of SASHS auctions should be set in terms of the number of SASHS providing an electricity service . Geographical diversity with different auctions per region would ensure the adoption of a minimum amount of SASHS in a given geographical area . Financial solvency but not technical reputation should be required . Otherwise only the incumbents would be able to participate in the auction . The choice of technology specific price only sealed bid single item auctions brings benefits in terms of economies of scale lower support or transaction costs and a greater transparency or simplicity . A correction factor on the remuneration which accounts for the quality of the service as applied in the Peru auction is suitable for this type of auctions . Finally provision of technical information which facilitates the participation in the auction and the implementation of a non disclosed ceiling price are deemed appropriate . In contrast given the low presence of local companies in the Peruvian PV market the adoption of local content requirements would lead to higher support costs without significantly increasing the local development potential . | An analysis of the design elements and functioning of auctions for stand alone solar systems in Peru. Lessons for the effective and efficient design of stand alone solar systems auctions are inferred. The auction volume should be set in terms of the number of systems providing an electricity service. Different auctions per region would ensure the adoption of a minimum amount of systems in a given area. Financial solvency but not technical reputation should be required. |
S0973082619312682 | Anaerobic digestion has received significant attention in recent years due to dual benefits of waste diversion from landfill and bioenergy recovery . Among various temperature regimes digesters operated under thermophilic condition has potential to provide several advantages over mesophilic and psychrophilic conditions which include faster degradation of organics and higher energy recovery . However the operation of thermophilic digesters requires closer monitoring and control due to an additional risk of ammonia inhibition and irreversible acidification through the accumulation of volatile fatty acids . Conventional strategies to alleviate instabilities in thermophilic anaerobic digestion process have been focused primarily on the development of robust microbiome and co digestion of complementary substrates . On the other hand emerging strategies include the integration of digesters with microbial electrochemical systems and amendment of conductive additives . This review provides a critical overview of these strategies and summarizes research gaps to guide researchers and practitioners in the future research . | Process instabilities due to ammonia inhibition and acidification are reviewed. Methods for improving process stability in thermophilic digesters are summarized. Research gaps associated with the implementation of these methods are identified. |
S0973082619312797 | This paper introduces the concept of renewable energy contingencies that represent long term extended variability of variable renewable energy resources namely significant periods of low wind solar availability . These contingencies have not received much attention to date but are likely to emerge as a major issue in some countries such as India as the share of VRE increases . Using 38 years of climate model reanalysis data for wind over India we demonstrate that low periods of wind contingency below long term national average of 5m s can extend for more than 100 days in several zones some of which are deploying large wind farms . Even in some of the best wind resource areas in India with long term average wind speed close to 7m s low wind days can extend up to 60 days . We propose a four step methodology around a co optimization based energy ancillary services dispatch model to assess the impact of renewable contingency and implemented it for the state of Tamil Nadu the most wind rich state of India . We have estimated that annual renewable contingency cost impact of 5GW additional wind in Tamil Nadu to be in the range of US 2776 million pa. Planning analysis should embrace the concept of renewable contingency to recognize these costs and put in place necessary spinning reserve and back up generation resources . | Introduces the concept of renewable contingency around long term variability of RE generation. Low periods of wind contingency below long term Indian national average of 5m s can extend for more than 100 days. We have estimated that annual renewable contingency cost impact of 5GW additional wind in Tamil Nadu to be in the range of US 2776 million pa. |
S0973082619312979 | Rural electrification has advanced rapidly in many developing countries . Under conditions of poverty and weak infrastructure however households face a risk of backsliding . We use two rounds from the ACCESS survey of rural households in six northern Indian states to explore factors that drive losses in household electricity access . About 7 of households with electricity in 2015 lost it by 2018 . We identify household wealth and off grid access as major drivers of lost energy access . A standard deviation s increase in a household s wealth index reduces the likelihood of disconnection by 1.5 percentage points . Off grid households are 8 percentage points more likely to lose access than grid connected households . These findings underscore the importance of defending realized gains in countries where household electrification is driven by policy while rural poverty remains prevalent . | This study analyzes the predictors of loss of access to electricity. We rely on a representative survey panel data of more than 8000 households in India. We find that households with lower income and formal education levels are more likely to lose access to electricity. Infrastructure and geographic factors do not predict loss of access. |
S0973082619313444 | The penetration levels of renewable energy sources energy storage systems and electric vehicles are increasing with the increase in the demand to solve energy and environmental issues . These distributed generators and energy storages can be efficiently managed in a DC smart grid by coordinated control . This paper proposes novel management schemes for DC systems to improve the reliability of power supply and improve the introduction ratio of renewable energy sources . The proposed DC smart grid includes multiple DC microgrids . These configurations and control systems must be designed on the assumption of islanding operation of DC systems . In the islanding power system with the high penetration of RES not only the utilization of energy storage but also load shedding and RES control is important . Hence an efficient control strategy by using a storage battery fuel cell and electrolyzer units heat pump units and a photovoltaic system is presented for stable islanding operation of DC microgrid . As the most important concept a pseudo Droop control is proposed that utilizes the characteristics of the PV module . The pseudo Droop control enables the PV system to suppress the output power properly by using a simple control system without the maximum power estimation . Fault ride through protection for DC system is also adapted to the DC distribution lines . The performance of the proposed DC smart grid is demonstrated through MATLAB Simscape Electrical | Novel management schemes for DC microgrid are proposed. The pseudo Droop control mode of a PV system contributes stable islanding operation of DC microgrid. Simulation models and control schemes of various electrical equipments are presented. The fault ride through protection for DC system is adapted to DC distribution lines. |
S0973082619313894 | In this short communication piece we draw attention to the discussion on policies for reducing energy poverty in European Union member states . We urgently need a policy approach able to support the transition from the current rising levels of energy poverty to a sustainable community with a greener and healthier future . Analysing energy prices the policy framework and household income we conduct a preliminary investigation of energy poverty from a macro level perspective and associated policy interventions in the EU . Obtained from a non classical fuzzy set qualitative comparative analysis our results clearly show that energy poverty is a product of substantial interdependence that may be summarised in two paths low or median household income and energy policy focus and high energy prices and energy policy focus . Surprisingly our findings indicate that an energy policy focus is found in EU member states with the highest levels of energy poverty . One step further we also offer an insight into the absence of energy poverty where social policy seems to play the key role . Taken together we argue that member states facing above average energy poverty are captured in an energy poverty trap whereby the existing energy policy focus does not yield the desired results and the social policy is often too costly to implement due to the problem s magnitude . Our main concern is that prioritising any of the policies may slow down the transition to a sustainable energy society . We therefore call on scientists to not only further examine the energy poverty phenomenon but to also participate in creating effective policies . | Energy policy focus is present in EU states with the highest energy poverty. Member states with low energy poverty have social and energy policy focus. Policy efficacy depends on the scale of the problem and situation in the EU states. Qualitative comparative analyses enrich investigation of energy poverty. |
S097308261931422X | Household fuel substitution has been a crucial step for controlling air pollution in China but the performance evaluation of household fuel substitution policies is overlooked . This study capitalized on the opportunity to use data collected during the household coal replacement program in North China to evaluate the effect of a mandatory policy on fuel substitution at the micro level . The results indicate that there is a significant effect of the coal replacement program on fuel substitution as we expected . The coal to electricity policy is effective in achieving the goal of a clean winter but not a warm winter due to the decline of delivered energy while the high quality coal replacement policy results in better performance in delivered energy but no improvement in indoor air quality . It is recommended to prioritize supporting measures on both the supply and demand sides before implementation along with undertaking differential measures during the implementation phase to better address energy inequality . | China s coal replacement program improves household energy structure. Coal to electricity policy worsens delivered energy but improves indoor air quality. Higher quality coal replacement policy only achieves the goal of warm winter. Mandatory fuel substitution should consider energy affordability and energy infrastructure. Differential measures are needed to ameliorate the policies. |
S097308261931659X | Modern buildings are operationally classified as fully naturally ventilated fully mechanically ventilated and conditioned or intermediary . Each strategy implies the selection of different internal comfort models and controls e.g . adaptive thermal comfort operable windows in FR and static thermal comfort non operable windows in AC and different energy consumption and carbon emissions with FR being the least and AC being the most . In each instance the choice of strategy is dictated by the designer with little choice for the occupants . Here we ask the question what operational mode would occupants select given complete freedom We examine this question using real concurrent data from three offices of similar size and use . In each occupants have complete freedom in adopting FR AC or a series of intervening MM strategies . We use monitored data on window and air conditioning operation combined with internal and external thermal conditions to create validated computer models for each office . We discover the true operational mode of each office by comparing the computer model against 23 different scenarios using Dynamic Time Warping for binary and Euclidean distance for continuous operative temperature time series . Strikingly results demonstrate that while each office used divergent strategies across the seasons the indoor conditions were very similar and attainable through NV alone . This suggests that while a purely NV strategy is likely to deliver indoor thermal comfort understanding occupant motivation and educating them on the impact of AC operation is needed to minimise energy use . | We evaluate the energy performance of mixed mode office buildings. We investigate what operational mode occupants would select in a mixed mode office. We evaluate multiple behavioural patterns for the AC an NV systems. We show that occupant priority could change how buildings are being designed. |
S0973082620302179 | The present study investigates the combustion process of the producer gas from a gasifier cookstove for four solid biomass fuels wood pellets wheat straw sheep manure and cow manure . It was found that more primary air and or a deeper fuel bed reduces tars in the producer gas and increases the combustion efficiency especially from low ash containing WP . At higher air supply rates indications of a strong influence from the fuel ash content on the emissions were found . Although more combustible gases and fewer tars are produced in the conversion process a substantial increase in particulate matter emissions is noted . At low air supply rates the emissions of particulates with an aerodynamic diameter 2.5m PM | Investigation of the producer gas combustion from a gasifier cookstove. Four tested fuels wood pellets wheat straw cow manure and sheep manure. Higher primary air supply and a deeper fuel bed increases the combustion efficiency. At lower air supply rates relatively lower emissions of both PM and CO are achieved. Emissions appear to be influenced by the release or retention of ash constituents. |
S0973082620302301 | The rural electrification based literature reports a limited knowledge of the long term socio economic changes that electricity access can bring in remote contexts and the consequent feedback on electricity demand . Such lack of understanding causes an inefficient allocation of economic resources for rural energy projects and inappropriate sizing processes . We model the multifaceted dimensions of the rural electricity development nexus by formulating a system dynamics model based on a Tanzanian case study and using 13 years of data for calibrating it . The modelled structure provides the first quantitative step in the research committed to develop an appropriate modelling framework for deriving policy insights regarding the electricity development nexus and the evolution of electricity demand for rural areas of developing countries . The simulation results show and highlight the dynamics behind the structural behaviour of some socio economic system variables the exogenous determinants and the complementary activities that allow electricity access to foster local socio economic changes which in turn supports the growth of electricity demand . Our findings allow increasing the understanding on the complex electricity development nexus and providing a novel modelling framework for projecting the electricity demand for rural settings . | We employ System dynamics to investigate the rural electricity development nexus. We develop a simulation model for long term projections of rural electricity demand in Tanzania. Calibration shows a mathematical good fit between data and model results. We find that the electricity development nexus is driven by both endogenous and exogenous dynamics. A modelling framework is provided for further policy testing on the electricity development nexus |
S0973082620302337 | Mini grids are increasingly filling the supply gap between government supplied electricity and the requirements of households and enterprises . We present a descriptive analysis of enterprise development within a large mini grid based rural electrification initiative launched in India in 2015 . Using data from two surveys conducted with 229 enterprise operators we explore the change in aspirations among enterprise owners and the impacts of longer duration of reliable electricity on key business outcomes . We find that improved quality of electricity from mini grids leads to a shift towards using mini grids as the primary source of electricity transition from lighting to productive uses of electricity and increased aspirational demand for electricity among enterprise operators . Further we find a positive relationship between increased hours of reliable electricity supply and extended hours of operation and customer footfall but not with revenue generation . Our findings suggest that mini grids offer an important opportunity for enhancing local aspirations for business development and should be an integral part of policies focused on rural enterprise development . | We surveyed 229 enterprises connected to solar mini grids in September 2016 and June 2018. Enterprises shift towards using mini grid electricity as their primary source. Enterprises adopt more productive loads over time and reveal an increase in aspirational demand for electricity. Longer duration of reliable power is correlated with increased operational hours and customer footfall but not revenue. Mini grids can benefit enterprise development by increasing aspirations and allowing experimentation with business. |
S0973082620302349 | How beneficial is basic energy access typically lighting and mobile charging for rural households Despite research on the economic impacts of basic energy access few studies have investigated how it changes household behavior . Here we report results from a randomized controlled trial in rural Uttar Pradesh India which identifies the behavioral impacts of providing solar lanterns to households that normally rely on kerosene as their primary source of lighting . Eighty nine of the 184 households participating in the study were given a free high quality solar lantern . Comparing changes in responses from the baseline questionnaire and an endline questionnaires administered six months later we find that the lanterns reduced energy expenditures improved lighting improved satisfaction with lighting more use of lighting for domestic activities and improved satisfaction with lighting for domestic activities . Overall our results show that basic energy access can offer substantial benefits within the households even if broader rural economic transformation is not plausible . | Measure effect of basic lighting on rural Indian households behavior and satisfaction. Solar lanterns reduced energy expenditures while increasing lighting. Basic lighting improved satisfaction with lighting and perceptions of solar. Time spent on domestic activities requiring lighting e.g. reading also increased. |
S0973082620302350 | Liquefied petroleum gas is considered to be a clean burning domestic cooking fuel across the world . The Government of India is promoting use of LPG as cooking fuel among Indian population . Refilling of LPG is not affordable to poor families . It is difficult for the Government to reduce price of LPG cylinders . In such a situation to make LPG affordable it is necessary to investigate methods for efficient utilization of LPG . | Three common cooking processes are selected for experimentation. Round bottom pot is found to be consuming less LPG than flat bottom pot. For efficient cooking process optimum pot size is important. Each gram of LPG saved by each family will save huge amount of national wealth. |
S0973082620302362 | Off grid renewable energy technologies are important in improving electricity access for rural communities . However methods for ensuring their sustainable operation are often poorly understood . In this article existing approaches for the assessment of off grid projects are examined . Reliability of the technology financial viability and community engagement are identified as the 3 key areas governing the sustainability of projects . Focusing on these areas a methodology is proposed to understand the sustainability of micro hydropower plants . A mixed methods approach including a maintenance assessment and interviews with managers operators and consumers is used to evaluate 24 sites in Nepal . Technically the results of the study showed that trained operators delivered a higher standard of maintenance however technical issues were identified that arise during the design manufacture and installation phases . The financial viability of plants was aided by charging consumers based on consumption whilst plants with a higher rated capacity tended to benefit from a larger number of productive end uses . Community engagement was fostered through the local identity of the plant however this was threatened by societal changes . Inherent features of the site such as rated power and the population density internal resilience to short term shock events and long term external development were found to affect the sustainability of plants . | Inherent site features affect the sustainability of micro hydropower plants. Internal short term events and long term external changes affect the plants. Threats to reliability can develop during the design manufacture and installation of technology. Consumers are often willing to pay more but low tariffs reduce the available plant income. |
S0973082620302386 | Ghana is one of the few countries within the sub Saharan region which has been successful in reducing energy poverty . However ensuring energy security affordability and environmental sustainability remains a significant challenge for the future development of the sub region . Here we examine how the electricity supply can evolve into the future to meet potential emission obligations for the period of 20202040 . A generation expansion planning model which is able to incorporate the reality of fuel shortages and fuel switching typical of a developing country s power system is used . In doing so we generate a range of emission reduction costs that provide important benchmarks for the relatively under studied sub Saharan region and identify drivers of these costs specific to developing countries . Results indicate that the total discounted cost in expanding generation to meet the demand for all scenarios range from 1317 billion US while the expected emission ranges from 99189 mtCO | A long term MILP generation expansion planning model was developed. The model handles unpredictability of energy policy using several scenarios. Total discounted cost in meeting demand by 2040 ranged 1317 billion US . The cost of meeting different emission targets is estimated and ranged 1139 US tonne. |
S0973082620302398 | The Indonesian Government in the last decade attempted to increase modern energy consumption through the implementation of the Liquid Petroleum Gas conversion program and the construction of numerous power generators . The attempt hoped to increase access to modern energy . This study investigates the Government modern energy projects by assessing both the accessibility and affordability of modern energy consumption in urban rural areas and across different income level households . This study measured the changes in energy access in different household categories as well as the energy burden of each household category using descriptive statistics . The present study confirmed the roles of access and income in energy spending using multiple regression analysis . The result showed that household access to modern energy significantly increased in all household categories . However access to rural households and low income households still needed improvement . Besides there was no proof of energy poverty in low income households . The results also revealed that modern energy access income and head of household education were the major determinants of energy spending especially for low income household and rural areas . Hence if Government wants to improve energy consumption households are willing to consume modern energy if the supply is available . However the education and financial ability will also be main consideration in determining energy consumption level . | The modern energy program significantly improved modern energy access in Indonesia in the last ten years. Indonesia s share of energy spending was still below 10 even for low income household. Modern energy access income and head of household education were the major determinants of energy spending. Government need to encourage LPG access to rural areas and consider improving education to increase electricity consumption. |
S0973082620302404 | Solar inverter providers optionally offer plant operators online access to their installed photovoltaic systems . Benefits consist of better system monitoring faster response to maintenance needs and a more comfortable data acquisition . Data mining from an online database enables a comparative statistical analysis for a large number of plants about specific productivity parameters emission reductions and monetary savings . Restriction of information usually confines the progress of PV systems . Due to this situation the Sunnyportal website managed by one of the most important world provider of solar inverters does not delimit the visualization of their own systems . In addition there is unrestricted access to their available plants in cases where the owners set the status of their plants as public . This study gathered and analyzed information on photovoltaic installations in Mexico with free access to production data . The results show an increase of almost 700 in the number of registered plants in Mexico with exponential growth since 2012 . Mexico still shows a lack of studies regarding the monitoring of PV systems because available data are scarce . The specific productivity rate of the PV systems primarily depends on solar irradiation on site weather conditions air contamination the technology employed correct engineering and plant maintenance . Based on data obtained conclusions are drawn concerning preferences and performance of Mexican PV plants . The most both surprising as well as important result is that there is no correlation between specific productivity and average daily on site irradiation . | PV systems in Mexico generate in the range between 90 and 125 kWh kW. month. Specific production of PV plants in Mexico is less than the projected production. Solar irradiation is overestimated in comparison to other factors. Only a slight increase in productivity with increasing irradiation is observed. |
S0973082620302416 | Electricity access and appliance usage are integral parts of developing a modern economy in rural areas . Unfortunately many households in rural India struggle to access reliable electricity and therefore are unable to power appliances throughout the day . We use household survey data from 10 249 households across the Indian states of Bihar Odisha Rajasthan and Uttar Pradesh to explore potential drivers of electric appliance usage . By applying a series of linear and nonlinear models we find that grid connected households have more electricity available to them and use significantly more electricity to power appliances in each of four designated household appliance categories lighting cooling entertainment and housekeeping . Households using alternative power sources including solar home systems and mini grids exhibit high uptake and use of lower level appliances in the lighting and cooling categories but much less so in the entertainment and housekeeping categories . Grid access is also correlated with higher electricity availability than alternative sources . Electricity availability is shown to be a highly significant predictor for powering appliances for longer time periods in all categories but especially for more easily attainable appliances in lighting and cooling categories . | Empirical analysis of appliance usage in rural India. Grid access is associated with high levels of appliance usage. Available hours of electricity supply per day is a major driver of appliance usage. Improving availability of electricity supply through the grid can increase appliance usage. |
S0973082620302428 | Electric cooking has the potential to improve quality of life for people who cook using biomass both by improving health by eradicating harmful emissions and by removing the need to collect fuelwood thus freeing up time for other activities . This paper reports on a study that introduced electric cooking as an alternative to biomass based cooking in 10 households in Simli a rural Western Nepali community to assess its feasibility in rural off grid contexts . Quantitative and qualitative data from a cooking diary study and electrical mini grid data were collected assessing the compatibility with micro hydropower grids and Nepali cooking practices . Datasets of Nepali cooking practices and meal energy requirements were generated revealing that generally two meals are cooked per day and that on average electric cooking consumes 0.25 kWh day and 0.14 kWh meal . Participants simplified their cooking practices and found chapati hard to cook on the induction hobs due to inexperience with the cookers . Conversely dal and rice were found to be easy and fast to cook in pressure cookers on the hobs leading to a switch from cooking chapati vegetables based meals to dal rice based meals . Fuel stacking was common with participants reverting to their biomass stoves to cook chapati and due to a lack of reliable electricity supply . Participants found that the transition to electric cooking provided more time for households due to the reduction in length of time to cook a meal and less time required to collect firewood and enjoyed cooking on the stoves due to elimination of indoor air pollution . The electrical data analysis showed that control issues voltage instability and limited micro hydropower plant capacity provide obstacles for electric cooking especially as it becomes more widely practiced . Nepali people typically cook at the same time as peak demand for electricity exacerbating the problem of limited capacity in villages like Simli . Only three households continued to use their electric stoves regularly due to a lack of reliable electricity supply showing that widespread adoption of electric cooking is currently unfeasible . The running costs of electric cooking were lower than the effective labour time costs of fuelwood collection but initial capital expenses for the electric cooking system and monthly electricity costs are a further barrier to adoption in rural Nepal . | Electric cooking was trialled in ten households on a micro hydropower mini grid. Cooking diaries showed that Nepali cuisine is mostly compatible with induction hobs. Dal and rice were easy to cook with participants preferring the lack of smoke. Fuel stacking was common especially for cooking chapati and during power outages. Considering equivalent cost electric cooking is over 50 cheaper than fuelwood. |
S097308262030243X | Cross border power trade in the Eastern Africa Power Pool has been very low for nearly 15years since its inception in 2005 . This analysis uses a least cost generation and transmission capacity expansion model to assess economic and CO | Eastern Africa Power Pool holds significant potential for economic trade where the current trade represents only 0.4 of regional demand. The analysis conducted for 2020 2030 shows encouraging prospects for EAPP to potentially gain 7.6 billion from a Shallow level of integration. A Tight integration that requires generation and new interconnection plans optimized at a regional level would increase benefits to 18.6 billion. Volume of trade needs to grow 10 fold to 4.1 of demand for a Shallow integration and 11.2 of demand for the Tight integration scenario. |
S0973082620302441 | Electric vehicles are widely heralded as the silver bullet for greening personal transport . However their eventual impact in South Africa a developing country with a low capacity carbon heavy grid is questionable . This paper examines the potential impact of electrification of the vehicle fleet in South Africa and explores the concept that large employers could take advantage of the country s abundant sunshine and provide photovoltaic solar carports for employees to charge their vehicles while at work . We assess the extent to which this would reduce the potential burden on the national grid and also consider the economic perspectives of the vehicle owners and the service providers . Our assessment employs a mobility model and a battery model for the vehicles and solar simulation with measured data for the PV generation . We show that without the provision of additional solar generation charging four million vehicles from the grid would exceed the grid s capacity . Further the carbon footprint of an electric vehicle charged from the grid would be greater than that of a petrol fuelled vehicle negating any potential benefits of electrification . However we demonstrate that photovoltaic charging at work renders electric vehicles more carbon friendly than petrol equivalents and has substantial financial benefits for the vehicle owner the service provider and the grid . | We assess the impact of the eminent introduction of EVs to the South African grid. As mitigation we propose at work charging with grid tied PV carports at the employer. Perspectives from the generator owner and carport owning employer are reported. Financial impact emissions impact peak load and net energy impact assessed. Despite CO2 dependent grid PV carports make EVs more efficient than combustion engines. |
S0973082620302544 | Industrial process heating has been identified as a potential field for solar thermal applications . In this paper a comparative study was carried out on the performance of an individual solar collector under laboratory conditions and performance of the collector array under field condition . Compound Parabolic Concentrator has been used as a solar collector for the application of boiler feed water preheating . The characterization of CPC has been done in liquid phase with water as a working fluid as per the standard IS 16648 2017 . The optical efficiency of the CPC is found to be 64.8 under standard test conditions . In the field total 200 number of CPCs each having 3m | There are many parameters which affect the performance of the solar collectors under actual field conditions which are often not given due consideration which creates a gap in the expected output and the actual performance of the solar field. The objective of the present study is to compare the performance of the CPC collector under standard test conditions and at actual field conditions. The study will help in designing the solar field considering the parameters responsible for lower performance under actual field conditions which will give more accurate performance results in the field. Comparison of available test standards for testing of solar thermal collectors was done. Performance of the compound parabolic collector was tested as per IS 16648 Part 5 2017 in the test centre. Field performance of collector was evaluated while integrated with industrial process heat application. Reasons of performance deviations in standard test conditions and field operation have been analyzed which can be considered while designing the solar system to meet the required heat demand. |
S0973082620302556 | The sustainability of energy use in the residential sector has relevance for global initiatives to achieve sustainable development and limit climate change . Using the city of Dar es Salaam in Tanzania as a case study we look at how national energy policy has influenced household cooking energy use between 1990 and 2018 and how energy policy could achieve further progress to realise national and global priorities . The study involved questionnaire surveys of households retailers transporters and producers of charcoal semi structured interviews with government officials and non charcoal fuel suppliers price data collection a comparative analysis of prices and taxes for different cooking fuels and policy and document review . Trends in energy policy and demand for different fuels are compared . We find that Tanzania s national energy policies have focused on achieving an energy transition from biomass to electricity and fossil fuels with an increasing focus on supply side issues . Fiscal policy tools have been used effectively to reduce demand for kerosene while increasing demand for liquefied petroleum gas . However this has not resulted in a transition away from biomass with most households using multiple fuels . Charcoal remains the cheapest and most widely used fuel reflecting the strong influence of price in consumer fuel choices . Energy policy needs to acknowledge the continued dominance of charcoal in urban energy use . In the context of rapid urbanisation and increased energy demand there is a need for sustainable urban energy planning across a range of fuel types including charcoal in ways that balance economic social and environmental outcomes . Greater inter sectoral coordination is needed to improve the sustainability of urban residential energy supplies . | Urban households in Tanzania continue to prefer charcoal despite a policy of fuel switching. Fiscal policy tools have influenced households to switch from kerosene to LPG. Charcoal is preferred by consumers because it provides the cheapest energy. We recommend policy measures to improve charcoal s social and environmental outcomes. |
S0973082620302568 | This article aims to present historical rate of decoupling and based on that determine the scope for India to increase its mitigation beyond the NDC commitment . Empirical evidence on nature and rate of decoupling between energy related emission and economic growth for the period 199091 to 201213 in India is presented . In addition to estimating the magnitude of decoupling elasticity decomposition analysis is also applied to understand how the four factors activity growth energy intensity change structural change and fuel mix change are driving the change in emission in India . Decoupling elasticity and Log Mean Divisia Index methods are used for decomposition . The results indicate presence of relative decoupling in India . The industrial sector leads among the four sectors agriculture industry services and power generation in achieving this relative decoupling mostly through improvement in energy efficiency and some structural changes . Results show that even in the business as usual scenario if India acts upon individual sector level mitigation potentials it has the potential to raise mitigation ambition beyond current Nationally Determined Contributions without adversely impacting economic growth . With continued high share of coal in the energy mix it is going to be difficult to achieve absolute decoupling . | Relative decoupling is increasingly happening in India since 199091 but more can be achieved. Industrial energy efficiency improvements explain most of the relative decoupling. To achieve unprecedented absolute decoupling high share of coal in total primary fuel mix is a major barrier. Untapped efficiency and fuel shifts potential can help in raising ambition beyond the current NDC. Raising NDC ambition through sectoral actions is not in conflict with economic growth. |
S097308262030257X | Efficient and effective thermal management of Li ion battery pack for electric vehicle application is vital for the safety and extended life of this energy storage system . In this paper the thermal management system of a battery module is presented as an integral part of the electric vehicle air conditioning system . The refrigerant is bifurcated from the main system through a pipe and expansion valve and guided to the battery module compartment consisting of 64 18650 type Li ion battery arranged in the form of 88 array . Several experimental strategies such as expansion valve throttle level thermostat sensitivity and proportional integral derivative control algorithm are investigated . The results indicate that a larger openness of the throttling valve avoids superheating of the refrigerant and maintains the maximum temperature difference in the battery module around 2C . Additionally thermostat sensitivity and PID control algorithm is found to be able to offer effective thermal management for an electric vehicle battery pack . | The battery thermal management is integrated with the vehicle air conditioning. Battery temperature control by the valve openness and thermostat sensitivity. The PID control algorithm is found to be an effective strategy. |
S0973082620302581 | Biomass burning improved cookstoves are often seen as a promising intermediate technology solution along the path of household transition to cleaner cooking . This study reports on the results of an experimental evaluation of a carbon finance enabled program conducted in rural villages in Rajasthan India . Half of 40 purposively selected treatment villages were randomly assigned to an early intervention group that was offered a package of two biomass fuel ICS one year prior to the other half . Analysis of data collected prior to the second phase of the intervention shows that adoption of ICS reached nearly 46 in the group exposed to the intervention and that households largely held positive short term views of the effects of these technologies . Moreover we found evidence of both time savings and reductions in fuel use among intervention households . Consistent with the wider literature on the limitations of biomass burning ICS however we failed to detect consistent effects on self reported respiratory health . Findings were generally consistent across simple and difference in difference estimates of impacts and suggest that biomass burning ICS can deliver benefits even when they offer few improvements in health . | Impacts of a carbon financed improved cookstove ICS intervention were assessed using a randomized roll out. Adoption of the biomass ICS in the target population over the first year was high reaching 46 . Households saved time and reduced solid fuel use by adopting the ICS but there was no evidence of health benefits. Impacts were generally robust but not always precisely measured to several estimation strategies. |
S0973082620302593 | A transition towards a sustainable energy system is a challenging process that involves multiple stakeholders with differing viewpoints . Several transition pathways are possible but the decision regarding which pathway to follow should be based on a justifiable and transparent framework that accounts for the concerns of all relevant stakeholder groups . This study proposes a participatory stakeholder analysis process that includes a two dimensional power interest matrix and fuzzy logic to define and classify relevant stakeholder groups . The proposed framework was implemented to recognize the relevant stakeholder groups of the Icelandic energy system and assess their salience . The defined stakeholder groups were then evaluated based on two attributespower and interestusing data collected from a web based questionnaire . Considering the wide range of the attributes values for the many stakeholder groups fuzzy logic was applied to plot a 3D decision surface which provided a more accurate assessment of stakeholders salience . The generated power interest map visualizes the dynamic influential level of stakeholder groups when it comes to decision making concerning sustainable energy development . The fuzzy decision surface shows a more accurate image of the difference in the degree of power and interest and saliences of the stakeholder group . Results reveal that Decision makers Industrial Users Professional Interest groups and Energy Producers have the highest salience and are the most influential stakeholder groups concerning decision making . Less influential stakeholder group such as Landowners exhibit a high degree of variation in influential level across the sustainable energy themes . The findings suggest that Icelandic decision makers responsible for energy development face a complex challenge when it comes to designing and implementing a policy that is approved across all stakeholder groups . This study offers new insights to policymakers on the most influential stakeholder groups and the variation of influential level across stakeholders groups in the Icelandic energy system . Understanding the power and interest of different stakeholders can improve the decision and policy making process and promote a successful transition to a sustainable energy system . | Participatory stakeholder analysis of key stakeholder groups in the Icelandic energy system. Stakeholders map compares the power and interest levels of stakeholder groups. Fuzzy logic was applied for the dynamic classification of stakeholders. Delivers insightful information to policymakers towards sustainable energy transition |
S097308262030260X | In 2012 the Peruvian government launched the public private initiative for energy inclusion to promote equitable access to subsidised liquefied petroleum gas cylinders . The objective of this study was to explore cooking patterns attitudes towards the FISE programme and factors influencing LPG use in rural Andean Peru . Forty eight women from four communities completed a paper based questionnaire on cooking practices and demographic characteristics . They partook in focus group discussions and participant observation sessions . In addition we conducted 12 semi structured in depth interviews with local authorities FISE programme contractor officials and male family heads . Despite the large outreach of the FISE programme in the region discrepancies in the administrative practices of public and private partners made it difficult for FISE beneficiaries to obtain both LPG stoves and FISE voucher discounts . The complications experienced by households not connected to the electricity grid may serve as an illustration of this lack of coordination . The FISE programme inclusion criteria required a stable monthly electricity consumption of 30kW hours thus excluding families with prepaid electricity meters living in remote areas . Overall we found that the FISE programme did not lead to exclusive LPG use in our setting . LPG was the second preferred source of cooking energy after firewood and women only used LPG for preparing quick meals or for reheating meals . The main barriers limiting LPG use included purchasing costs difficulties completing other daily chores while cooking technologies not matching local cooking needs the need to save time and the perception that LPG affects the taste of food . Peruvian LPG programmes should harmonise their recruitment schemes and the FISE programme should modify its criteria to ensure the inclusion of all vulnerable populations . In view of the evidence obtained from other countries and the high prevalence of stove stacking practices LPG initiatives in rural Andean Peru merit from incorporating socio cultural dimensions and alternative cooking technologies adapted to local fuel preferences food cultures and cooking demands in order to achieve a sustained LPG transition . | The Peruvian national LPG programme FISE did not achieve a full energy transition. Food taste and time to complete daily chores were key barriers for LPG uptake. Lacking electricity or prepaid meters excluded families from the FISE programme. The FISE programme should modify its criteria to reach all vulnerable populations. |
S0973082620302611 | The identification of the best electrification strategy is a fundamental step to increase energy access in rural areas of developing countries . The objective of the present work is to propose a new geospatial based procedure for rural electrification planning able to select and design an effective energy system for a defined geographical region . The least cost solution among stand alone mini grids and connection to the existing national grid of non electrified communities is identified . Spatial information is exploited to compute renewable resources potential to identify populated areas subdivide them into clusters and to design the electrical network connecting the clusters consumers pursuing the minimization of costs . To this end an iterative minimum path algorithm has been developed by the authors . It is able to approximate the | A new comprehensive approach for rural electrification planning in developing countries is proposed. The approach allows selecting and designing the most effective electrification solution among grid tie and off grid systems. Geographical Information System data are used as the principal framework of the procedure. Innovative approach for grid topology optimization based on Steiner tree and Dijsktra algorithms. The procedure is validated with a real case study in Mozambique. |
S0973082620302635 | Hybrid microgrids represent a cost effective and viable option to ensure access to energy in rural areas located far from the main grid . Nonetheless the sizing of rural microgrids is complicated by the lack of models capable of accounting for the evolution of the energy demand over time which is likely to occur in such contexts as a result of the modification of users lifestyles . To tackle this issue the present study aims at developing a novel long term optimisation model formulation capable of accounting for load evolution and performing suitable investment decisions for capacity expansion along the time horizon . Multiple scenarios of load evolution are considered to evaluate the beneficial effects of this novel approach through the coupling of the model with a tool for stochastic load profiles generation . The results show how this implementation brings lower Net Present Cost to the project and improved correspondence between actual electricity demand and microgrid sizing . Finally a sensitivity analysis evaluates the robustness of the approach with respect to input data variability and the Loss of Load parameter . | Evolution of the load is a key factor in microgrid sizing usually neglected. A microgrid sizing tool is adapted to be able to consider time evolving loads. Trough stochastic programming the new feature is implemented in the source code. The novel method allows consistently decreasing system costs. First tool of its category to endogenously tackle the problem of load evolution |
S0973082620302702 | The increase in efficiency decrease in starting time and ease in manufacturing of rotor blades are the most desirable aims of research in the design of small scale wind turbines . A multi objective optimization study is carried out to analyze the performance of a small horizontal axis wind turbine in terms of the output power and the starting time for four possible combinations of linear nonlinear distributions of the chord length and twist angle along one meter timber blades . The blade element momentum theory is adopted for the calculation of the power coefficient and the starting time . The optimization is achieved through a genetic algorithm which simultaneously maximized the power coefficient and minimized the starting time . The most important contribution of this paper is the in depth comparison of the linear and the nonlinear distributions for chord and twist angle subjected to the aforementioned optimization which is not available in the existing literature in such detail . Results show that although the linear distributions have more deviation from the so called ideal distributions however the output power performance of the blades with linear distributions is competitive with that of the nonlinear ones . Moreover the results establish that the use of linear distribution can improve the starting performance at a lesser compromise of output power . This is of paramount importance particularly to promote harnessing the wind energy in developing countries as simpler distributions could facilitate the manufacturing of wind turbine blades . Apart from using the linear or nonlinear distributions for both the chord and the twist angle two other cases are also investigated including the linear distribution for the chord and the nonlinear one for the twist and vice versa . The analysis of these cases shows that choosing the nonlinear distribution for the chord would improve the starting while using the linear one would lead to more powerful blades . | Nonlinear linear distributions of the chord and twist are analyzed for small blades. Optimization method utilizes the output power and starting performances as criteria. Linear distributions for both chord and twist are recommended in low wind areas. Nonlinear distributions for both chord and twist are suggested in windy regions. |
S097308262030274X | Solar technologies promise to provide clean energy to the poorest populations . Motivated by observations of low quality products in the solar home system market this study analyzes the role of product quality in the transition to cleaner energy technologies in developing countries . Our systematic empirical analysis of the Ugandan solar home system market reveals several market segments . | This paper explores the role of product quality in the energy transition. It presents a systematic empirical analysis of the Ugandan solar home system SHS market. The study shows neither high nor low quality solar products offer a win win solution. Low quality products may enhance a swift and inclusive transition. |
S0973082620302751 | Solar photovoltaics are being promoted in various parts of the developing world for irrigation pumps as a clean energy source for use in remote areas to provide livelihood generation and in India additionally to address issues with grid supply . India has a well developed system of electricity distribution for irrigation but socio political issues in this sector have led to a system with poor quality supply for farmers and losses for distribution utilities . A technical solution is being sought through the following new paradigms offgrid solar photovoltaic pumps grid connected solar photovoltaic pumps agricultural solar feeders and High Voltage Distribution Systems . These paradigms have been evaluated in this work considering Maharashtra a representative state with an agricultural distribution infrastructure similar to many states of India . We conduct a comparison of the ALCC of the different technologies based on the seasonality of irrigation sizes of pumps and areal density of connections as reflected in the cost of infrastructure by using marginal costs for supply of electricity . Energy consumption of five agricultural feeders representing four main agro climatic zones of Maharashtra has been considered to provide context . The study finds that offgrid solar photovoltaic pumps are more cost effective than the current system when operated for more than 875h annually . Other than that most systems are more likely to be economically suboptimal in comparison to upgrading the current distribution system . Other researchers have proposed that grid connected solar photovoltaic pumps can be used to encourage farmers to reduce groundwater extraction through the use of feed in tariffs . This study finds that the economics do not support this contention . | Methodology to compare solar PV and grid supply for irrigation pumps. Seasonality of irrigation and density of pumps are important determinants. Net metered solar PV pumps will not promote reduction in groundwater usage. Improvement of the current grid system is likely to be more cost effective in India. |
S0973082620302775 | In this study we use water boiling tests controlled cooking tests and in home kitchen performance tests to analyze changes in fuel consumption and emissions resulting from low cost modifications to traditional open fires . The modifications consist of adding rock beds ceramic grates or metal grates to open fires . In both traditional and modified stoves cooking pots are supported over the fire using iron bars which is a common practice in rural Vietnamese households . The modifications increase airflow through the combustion zone and improve combustion efficiency . The rocks and grate also decrease the distance between the fire and cooking pot improving heat transfer . These low cost modifications improve stove performance in many categories 3858 reduction in wood consumption and 5184 reduction in emissions measured in WBTs 3437 reduction in wood consumption during simulated cooking with CCTs and 3145 reductions in per capita wood consumption measured during KPTs . Grates performed better than rock beds in nearly all tests . Surveys implemented in parallel with KPTs indicated favorable user perceptions of all low cost options . The modifications result in lower fuelwood consumption and emissions resulting in social and environmental benefits but they are unlikely reduce health impacts which many policies and programs now prioritize . Nevertheless there are numerous situations in which these options may be appropriate . In remote rural or otherwise marginalized communities clean cooking options may be inaccessible for the foreseeable future . Low cost modifications like rock beds and grates which require minimal training and changes in cooking habits could reduce the impacts of open fires . Similarly in places where clean cooking options are accessible but stove stacking with open fires persists these options could present a cost effective way to achieve a cleaner stack . | Modifying open fires with rock beds or grates is a low cost way to reduce impacts. Rock beds and or grates can be implemented where cleaner options are unavailable. Rock beds or grates to open fires reduce wood use up to 58 in lab tests. Rock beds and or grates reduce CO and PM emissions by 5184 in lab tests. Rock beds and or grates reduce wood consumption up to 45 in actual cooking. |
S0973082620302787 | Utilization of hydro power as a renewable energy source is now of prime importance in the world . Hydropower energy is available in abundance as a renewable source . For run of river low head reaction type Kaplan turbines mostly used . In this paper a parametric study has been conducted on a complex geometry of Kaplan blade through static and dynamic computational analysis by varying the blade profile at different angles in the CAD model . Blade geometry surface and design were developed in Creo using the coordinate point system on the blade . | A robust computational model for Kaplan turbine is developed and verified. Study and research work led to an enhancement of 5.43 in turbine performance. A method is devised that resulted in markable financial impact on monthly savings. |
S0973082620302805 | Solar home systems have seen rapid growth and have proven to be a viable source of electricity for households due to their capability to reach remote users that do not have access to grid systems . Based on a comprehensive literature review of 139 papers focussing on SHSs in Sub Saharan Africa this paper highlights the key trends research gaps and policy recommendations . The literature was categorised into four themes institutional technology viability and user centric . The review finds that the current primary themes of research are technology user centric and viability . This highlights the need for further research into the institutional barriers of SHSs as well as the regulatory frameworks and incentives needed to increase their adoption . The most popular topics discussed in the reviewed literature included SHS business models SHS design the energy demand of end users and barriers to SHS adoption . The authors also identified paucity of research in countries with low electrification rates highlighting new locations for SHS research . | The authors reviewed 139 papers focussing on SHS research in Sub Saharan Africa. Almost even split between technology viability and user centric SHS research with limited research on institutional issues. There is a gap in SHS research in SSA countries with low electrification rates. Most popular topics were SHS business models SHS design end user energy demand and adoption barriers. Need to develop stronger regulatory frameworks for SHSs and improved quality assurance through cross sectoral partnerships. |
S0973082620302817 | Reducing the burden of household air pollution could be achieved with exclusive adoption of cleaner fuels such as liquefied petroleum gas . However we lack understanding of how much LPG is required to support exclusive use and how household characteristics affect this quantity . This paper used data from 90 participants in the Cardiopulmonary outcomes and Household Air Pollution trial in Puno Peru who received free LPG deliveries for one year . Households with a mean of four members that cooked nearly exclusively with LPG used an average of 19.1 | Study participants in Puno used on average 19.1. None. kg of LPG per month. LPG use was greater with pig dog ownership wealth family size and LPG vouchers. Participants used LPG and biomass similarly but more often prepared lunch with LPG. The current subsidy in Peru covers only 25 of rural residents LPG needs. Programs must provide enough fuel for exclusive use to achieve potential benefits. |
S0973082620302829 | This paper presents a comprehensive energy management system based centralized control for a smart greenhouse integrating a microgrid with the aim to optimize and control the global internal environment and the crop growth . The objective is to develop an advanced and comprehensive energy management platform based model predictive control considering intermittent behaviour of renewable energy production energy and water storage dynamics as well as uncertainties related to climate conditions . A multi objective integrated optimization framework is proposed to manipulate the whole operation of the smart greenhouse that considers both forecasts and updated data collected from the available wireless sensor network . The MPC based scheduling is verified via a case study where its numerical results are depicted and discussed . | A comprehensive energy management based centralized control for a smart greenhouse integrating a microgrid is presented. An advanced energy management platform based MPC scheme to optimize and control the indoor microclimate is developed. A multi objective integrated optimization framework is proposed to manipulate the whole operation of the smart greenhouse. The MPC based scheduling is verified via a case study where its numerical results are depicted and discussed. |
S0973082620302830 | In this paper an iron scrap filled tube plate PV T system was designed and manufactured . Its annual performance was simulated and the simulation results were verified by experimental data . The simulation results showed that the annual output of electricity was 792.6MJ and the annual heat collection was 2558.3MJ under the standard annual meteorological data of Tianjin China . Simulation results demonstrated that the annual average generation efficiency was 15.5 and the annual average heat collection efficiency was 49.1 . Moreover the electrical power generation and heat collection efficiencies increased by 13.9 and 10.8 after being filled with iron scraps respectively . Subsequently the energy economic and environmental benefits of the new tube plate PV T system were compared with those of the traditional tube plate PV T system photovoltaic system and solar collector system . The simulation results also showed that the annual total energy savings and CO | An iron scrap filled tube plate PV T system is designed and manufactured. The annual performance of the iron filing filled system was simulated. The energy saving and economy of the iron scrap filled tube plate PV T system is compared with other systems. The results show that it improves the heat transfer and it saves energy compare with other three systems. |
S0973082620302842 | If hydrokinetic turbines are to make a significant contribution to small scale off grid power supply they will need to be affordable reliable and easily deployed at many sites not just a few with exceptional combinations of depth and high flow velocity . Few if any products currently on the market meet these criteria . This paper addresses the challenge of providing small scale electrical power and pumping from rivers in particular for villages in high rainfall tropical areas where there is no mains power not much wind or sunny weather in the wet season and not enough elevation for conventional micro hydro . Hydrokinetic power is proposed and candidate turbines are evaluated including multiple small axial flow turbines various forms of horizontal axis Darrieus turbines water wheels and belt turbines . The importance of channel blockage in enhancing turbine power output is discussed . | No hydrokinetic turbines currently available for rivers 1m deep. Most manufacturers assume 3m s flow for rated power. Almost never occurs. Long horizontal axis modified Darrieus turbine proposed. Simple passive variable pitch greatly improves starting torque |
S0973082620302854 | Currently feasible construction practices are not enough to reach zero energy buildings therefore European Union legislation states that new buildings and renovations should be designed as nearly zero energy buildings however design alternatives need to be carefully considered and selected before implementation . This study aims to investigate the effect of building faade elements and energy efficient building systems on reaching nZEB with two different design approaches . These approaches are investigated through the case of a selected office building s faade retrofit options in terms of energy efficiency and thermal comfort . In the first DA different design variables of a double skin faade are investigated and optimized in order to decrease the total amount of consumed energy and the best parameters are used in the design of the south faade . In the second DA the building retrofit aims to meet nZEB criteria by redesigning the south building faade via genetic algorithm optimization while providing thermal comfort in all months and reducing the number of discomfort hours . The investigation is carried out via building energy simulation of a selected office building validated by indoor and outdoor measurements . The results show that the parameters of the building faade can play a significant role in decreasing the energy consumption of the building and both DAs decrease total energy consumption while utilizing currently feasible and common building technologies . Yet in the second DA not only is the energy consumption lower but it also significantly decreases discomfort hours . | The building faade plays an important role in reaching nearly zero energy buildings by retrofit. The study investigates two design approaches to both reduce energy consumption and increase thermal comfort. Feasible and common technologies can play a significant role in decreasing a building s energy consumption. Double skin faades can show better performance in the Mediterranean climate when optimized by building energy simulation. Decreasing both the number of thermal discomfort hours and energy consumption at the same time is possible. |
S0973082620302866 | We describe resource assessment of rivers and a canal in the Upper Blue Nile Basin Ethiopia for hydro kinetic turbines . Various hydrodynamics methods are coupled with hydrological methods with the aim of transforming the measured flow rate or discharge into velocity data to determine the power density the available power per square meter of vertical flow area . We estimate the PD over the length of the rivers and canal and estimate the power density variation over the months of the year . The Gumara Gilgel Abay and Bahirdar Abay rivers in the Blue Nile Basin were studied along with the Koga irrigation main canal . Historical databases of yearly monthly and daily averaged discharge were used . The key elements of this analysis are converting discharge into velocity for PD determination and the period over which the velocity is averaged compared to the averaging time used to determine the HKT power curve . All software used in this work is publicly available . To predict PD ARC GIS was used to estimate the reach length and cross section from raster Digital Elevation Models . The hydraulic modeling of the velocity was done using HEC RAS software . Field measurements were conducted to validate the hydrodynamic model . The result of the study was cross sectional area average water velocity | Resource assessment of hydrokinetic turbines. Hydrodynamic and hydrological method. Time average of river velocity. Yearly monthly and daily average of power density |
S0973082620302878 | In the fundamental stage of resource assessment high quality wind speed measurements are required to estimate power production . However this high quality data is not always available and therefore the analysis of alternative sources becomes essential . In this work we analyze the ability of MERRA 2 to represent wind speed characteristics at 24 anemometric stations in Mexico . The assessment was carried out using the Pearson correlation coefficient between the observed time series and the obtained by interpolating bias corrected reanalysis estimated wind speed to all locations for different time averaging periods . Results showed that the reanalysis performance is not uniform throughout the country it depends on the time resolution local orographic conditions and the relationship between the local flow and the large scale circulation . Based on these results the country was subdivided into eight regions . The best represented region was the Chivela Pass where the winds are tightly linked to the interaction between the large scale circulation and the local orography . The worst performing regions were located where the land sea mask and orography at the reanalysis resolution may not be accurate enough to reproduce the station s wind speeds . Reanalysis estimated capacity factors exhibit large interannual variability in some stations which can have significant consequences for the operation of individual wind farms and the power grid . The results show that while caution should be exercised when applying reanalyses to wind resource assessment in Mexico reanalysis wind power estimates can be a valuable tool to investigate the feasibility and installed capacity requirements for Mexico to meet its renewable energy targets . | MERRA 2 performance is studied to represent wind speeds in 24 locations in Mexico. Reanalysis performance is not uniform improves as the time averaging period increases. Best performance is presented in the Chivela pass where large scale circulation domains. The worst performing regions may be associated with the land sea mask and orography. |
S097308262030288X | Despite increased access to modern energy services being a key development priority few studies have examined whether improved access is sufficient to facilitate universal energy use at the household level . Using micro data from Vietnam we study how a national grid expansion is translated into households electricity use over time . Our analysis reveals that household income is an important determinant of electricity consumption and that this relationship is highly nonlinear with respect to income . We find a greater degree of inequality in electricity expenditure than we do in income . This finding suggests that a rapid increase in electricity access may not translate directly into increased use of electricity for low income households and could potentially increase the gap in energy use between high income and low income households . Lastly we find that household characteristics such as the education level of the household head household size as well as the type of housing are important factors that influence electricity consumption . | Micro level analysis of the determinants of household electricity expenditure in a lower middle income country context. Household income is an important determinant of electricity use in a developing country context. Electricity expenditure has a highly non linear relationship with income. Inequality in electricity expenditure is greater than inequality in income. Policymakers should consider how to facilitate productive uses of electricity across the population. |
S0973082620302891 | Drum kiln with heat distribution pipe is a new design for vertical drum kiln . It is a small kiln for charcoal biochar and wood vinegar production . It consists of a 200l oil drum covered with fiberglass and galvanized steel as an insulator . The heat distribution pipe with slots is installed in the middle part of the kiln . There are four exhaust chimneys for smoke ventilation and wood vinegar collection . The chimneys are covered with condensers for wood vinegar condensation . Two types of biomass for this experiment were tamarind wood and corncob . For tamarind wood the drum kiln loaded about 40kg of wood with moisture content of 2024 using 1019kg of firewood . It took about 3.55h to reach maximum temperature and cooled down within 35h . In sum therefore it took about 8h for the complete tamarind wood charcoal process . The products were 1112kg of tamarind wood charcoal and 1213kg of wood vinegar . There was no incompletely carbonized wood and ash . Properties of tamarind wood charcoal were tested following ASTM D758215 and ASTM D586510 . Tamarind wood charcoal showed 5 moisture content 2021 volatile matters 68.769.8 fixed carbon 3.85.6 of ash and 3031MJkg | High energy conversion efficiency kiln. Movable kiln. Good quality charcoal and biochar. Wood vinegar as a by product. Enhancement for wood vinegar collection with condensers |
S0973082620302908 | The frequency of power outages being experienced in Sub Saharan Africa mean that traditional methods of electricity demand forecasting which rely on directly observed demand data are inadequate for use in projections . Nevertheless accurate forecasting methods are urgently required to ensure efficient power system operations and expansion planning . To address this gap we develop a novel method to estimate unsuppressed electricity demand for developing countries . This follows a bottom up approach based on socioeconomic data and a time use database developed from a householder survey which are used to generate household profiles using a Markov Chain approach . These profiles are then converted into electrical load time series by a series of appliance models using reanalysis weather data to accurately represent ambient conditions for the generation of cooling demand profiles . We apply our method to a Nigerian case study obtaining the first time series of unsuppressed residential electricity demand for the country using the first Time of Use Survey for Nigerian households . We validate our model outputs using the results of a small scale residential metering trial which yielded a correlation coefficient of 0.97 RMSE of 0.04 and percentage error of 6 between measured and model data . This evidences that our method is a credible and practical tool for electrical demand studies in developing countries . Using the model the forecasted domestic demand for Abuja Electricity Distribution Company ranges between 345 and 575MW while that of Nigeria ranges between 3829 and 6605MW . | A time series model of domestic energy driven by household activity enables the assessment of climate scenarios on demand. The first Time of Use Survey for Nigeria enabling representative stochastic modelling of individual and aggregate households. It includes a socioeconomic model which can be extended to vary the electrical appliance suite for energy efficiency studies. Model provides a means of cross validating simpler methods and examining the credibility of limited demand measurement data. It facilitates use of time series operation and planning approaches that are standard in Western nations. |
S097308262030291X | Equitable energy supply planning is nearly impossible in regions with limited data availability . Lack of representation among marginalised populations can perpetuate existing structural and socio cultural inequities despite aggregate improvements to energy supply . In Nepal this represents an acute challenge for the 460 rural municipalities recently tasked with improving supply provision for their constituents . Since the last census in 2011 the country has undergone significant political changes as well as suffering several natural catastrophes . In this context data collection and analysis methods are needed to support local decision makers in developing equitable energy supply improvement plans . This work highlights the role of disaggregated household energy supply measurement to capture contextual inequities that are typically lost in national or state level aggregates . Methods for efficiently collecting and analysing spatially representative household energy access survey data are described . Application and analysis of household surveys | Methods for disaggregated household energy supply measurement are described. These are applied on primary household survey data in western Nepal. 2357 . Supply inequities are more prominent for electricity than cooking which is poor overall. Spatial disaggregation indicates not only for whom but also where inequities exist. Equitable energy supply planning requires disaggregated energy supply measurement. |
S0973082620302921 | As countries start to implement the Sustainable Development Goals in their national development agendas reviews of the current policy environment are necessary to ensure that the goals are achievable by 2030 . The present study assesses the effectiveness of energy policy in Indonesia in supporting progress towards universal energy access a substantial increase in renewable energy deployment and improvement in energy efficiency . Laws and regulations related to energy were reviewed and their contribution to achieving the energy targets of the Sustainable Development Goals in Indonesia was evaluated in terms of policy effectiveness . Results show that providing electricity for the remaining 1.1 million households living in the outermost and least developed regions of the archipelago is very challenging . However Indonesia is still on track to achieve 100 residential electrification by 2030 as long as enough budget is allocated annually . Indonesia may not be able to provide access to clean cooking fuels and technology for everyone by 2030 . The current policy focusing mostly on gas for cooking will be less effective in reaching the remaining households that cook with solid biomass and usually live in poverty . Similarly the current policy scenario is not sufficient to allow enough progress to achieve the renewable energy target . Finally the assessment of energy efficiency policy suggests that sectoral energy use is shaped by variables and regulation not primarily intended to improve energy efficiency . | The electrification program as a national priority improves electricity access. The clean cooking energy target may be missed as policy focuses on gas use only. Regulatory uncertainties discourage investment in renewable electricity. Energy use is shaped by policies not primarily intended for energy conservation. |
S0973082620302933 | The former consensus on a link between energy consumption and improved well being of a country has been scrutinized by scholars for decades and is succinctly for the time being a contested thesis . Until the 1970s the relation of energy to well being was defined as linearly proportional and in a later period still as an increasing logarithmic function . Recent empirical research falsified the assumption of an overt link between well being and increased energy consumption in countries with high per capita energy usage . | First evidences for a Well being Turning Point WTP supporting a well being degrowth beyond high energy footprint threshold. The WTP is a novel argument to support degrowth from energy perspective. The WTP can be neither fully proven nor falsified with current data. The WTP is not visible when the fitting was population weighted. The WTP is not visible if oil exporting countries and some small countries are excluded. |
S0973082620302945 | Following the 21st Conference of the Parties the 2015 Paris Agreement on Climae Change strengthens the attempts of the European Union to decarbonize the building sector and to facilitate the transition from fossil fuels towards cleaner energy . The last version of the Energy Performance of Buildings Directive 2018 844 EU is human centric and requires the integration of indoor environmental quality assessment simultaneously with energy performance and cost optimal requirements . In other words efforts to improve the energy efficiency of buildings must actively contribute on reducing the building stock s climate impact while ensuring healthy indoor climate conditions wellbeing and productivity . This paper introduces the cost optimal analysis and indoor environmental quality assessment for nearly zero energy buildings in temperate climate . The study presents several nearly zero energy buildings scenarios for residential buildings which include measures that are either upgrades that can be implemented in the as built case study building or different other configurations of thermal envelope technical systems and on site renewable energy production . The cost optimal analysis results show that among the investigated scenarios the lowest global cost is achieved by the as built house which is an all electric building that has passive house envelope mechanical ventilation with heat recovery heat pump and solar collector . Furthermore the study reveals that with the implementation of PV panels the primary energy demand can be reduced with 55 at a global cost increase of only 3 . The results and data can be used to compare energy efficincy measures and the related costs between EU Member States . | Cost optimal levels of energy performance and indoor environment are investigated for a nearly zero energy building NZEB . Passive house design combined with PV panels results in net zero energy or greater energy production than consumption. Three of the proposed NZEB scenarios have a higher energy production than consumption. NZEB can be achieved with a lower insulation if it is combined with efficient technical system and or renewable energy production. Indoor environmental quality was assessed following a full year of measured data in the occupied building. |
S0973082620302957 | Many countries have set renewable energy targets in their electricity supply mix to encourage investments in renewable energy technologies . In developing countries however many of such targets are either abandoned or fall far short of the target date primarily due to issues of financing cost of electricity and level of unmet demand . This paper presents a Generation Expansion Planning model that can be used to assess such issues when setting a renewable electricity generation target . In particular the model can be used by developing countries to set renewable electricity generation targets that are in line with their financial ability and thus stand a higher chance of being achieved . Additionally the analysis offered can inform developing countries of the cost and benefits of a renewable electricity generation target policy . The usefulness of the model is demonstrated using Ghana as a case . The results indicate that Ghana will need a budget of not less than 1 of its GDP for generation capacity investment if it desires to achieve its 10 renewable electricity generation target by 2030 while keeping unmet demand at reasonable levels . If Ghana however enforces the target at its current capacity investment levels it risks raising unmet demand levels by an average of 4 per year and cost of electricity provision by about US 224 million annually between 2019 and 2030 when compared to the absence of a renewable electricity generation target . | A model for setting and evaluating a renewable electricity RE target policy is developed. Model allows for the estimation of impacts on levels of unmet electricity demand and cost of electricity provision. Cost Benefit analysis of the renewable electricity target policy is provided. A country must have in place adequate financial resources to benefit from transitioning to renewable energy. When constrained financially a RE target policy is likely to impact negatively on supply and cost of electricity. |
S0973082620302969 | A design and optimization procedure of simplified wind turbine rotors for small scale applications is presented . The need for this research has arisen from the recent national initiative of the government of Sri Lanka titled Battle for Wind Energy in promoting small scale grid connected wind plants for electricity customers under Net Metering scheme . The main objective of this research is to assist local developers to design optimum rotors for given electrical generators suitable for wind characteristics at specific locations . Another objective is to enhance local manufacturing capabilities by providing a design option of a simplified rotor blade geometry . A study on the correlation between population density of electricity customers and wind energy potentials was carried out to categorize the demand centres based on wind energy potentials in proposing series of small scale wind turbine designs . A unique and improved rotor design procedure is presented which attempts to match the point of maximum performance of a rotor with the design wind speed of a given location by considering generator performance . The new design procedure showed successful convergence on a unique blade diameter for each rotor configuration that allowed the design tip speed ratio to match the design wind speed . The performance evaluation of rotor designs showed that high solidity rotors work better on the low wind potential region while low solidity rotors dominate medium and high wind potential regions . The performance reductions of simplified rotor designs are not significant and therefore would be an effective way to enhance value addition through local manufacture . Lack of a rotor design procedure that considers generator performance . Identification of geographical locations most suitable for promoting small scale wind turbines . | Suitable geographical locations for promoting small scale wind turbines in Sri Lanka. Improved rotor design procedure considering generator performance. Design procedure for rotors with simplified blade geometry. Optimized rotor designs for different wind potential regions in Sri Lanka. Simplified rotor designs for different wind potential regions in Sri Lanka |
S0973082620302970 | Renewable energy cooperatives in Turkey have received considerable attention in recent years and the total number of cooperatives is 46 in 2020 . With increased environmental awareness and energy demand RECs aim the local and renewable resources to be used by the people of the region by creating an example venture model through cooperatives . The growth in the number of cooperatives has resulted largely from Turkish energy policy and arrangement of Renewable Energies Act . This study is aimed to identify energy cooperatives current situations advantages characterizing the implementation barriers RECs face and external factors . For this purpose an online questionnaire was carried out with REC members and questionnaires were sent to 468 members of 20 cooperatives via e mail and approximately 80 return was obtained 16 management board members were interviewed with categorized questions and RECs websites were examined as well . This paper presents an overview of This paper presents an overview of Turkish energy cooperatives in terms of organization financing membership technology policy internal and external barriers drawing on collected data . How to create a better understanding of energy cooperatives and contribute to the Turkish energy policy were discussed . RECs could be an example venture model to provide the local and renewable resources to be used by the people of the region . Also RECs can be an important building block of the energy transition in Turkey where consumed energy mainly imported from abroad and if RECs are to continue to play an important role in the energy transition policy makers are expected to support their growth . These findings may be a guide for further researches for Turkey . | RECs can be an important building block of the energy transition in Turkey. Differences in the development of RECs exist mainly regarding the finance. The main external factor in the development of RECs is policy. The amount of electricity produced is the most important indicator of success of RECs. |
S0973082620302982 | Small solar home systems have emerged as potential alternatives to grid electrification in rural sub Saharan Africa enabling households to make modest investments into their power systems and to modify those systems according to their changing incomes and power demands . In this work investigate how introduction of rural unelectrified households to basic electricity temporally stimulates increasing power demands . We use survey gathered data to show that once households get access to basic electricity they begin to realise its socio economic benefits and start to desire more luxurious appliances especially through social pressure and neighbourhood influence . These desires are realised temporally with activities that lead to increasing households incomes leading to increasing loads and thus to the modifications of the originally installed small SHS to meet those increasing load demands . Eventually cumulative increasing loads within a given community could lead to extensions of the grid to that area as total power demands now justify such investments . Basic SHS therefore potentially act as grid electrification stimulators leading to eventual grid electrification of a given community as an electrification policy developing communities should consider seeding unelectrified areas with SHS to stimulate power demands for eventual grid electrification . | Solar Home Systems SHS stimulate increasing power demands. Increasing power demands stimulate increasing household incomes. Increasing incomes translate into more appliances and thus to more loads. More loads lead to larger SHS installations. Larger SHS stimulate grid extensions to given villages. |
S0973082620303082 | As the largest carbon emitter China has launched the emissions trading scheme in 2013 . Since then whether ETS in China really help reduce carbon emissions has become a hot button issue . By far scholars tend to offer the macro level empirical evidence and the conclusions are at best mixed . Therefore we try to reveal the effect of China s ETS from the micro level by focusing on the policy executors herein the pilot firms . Based on the data of listed firms from 2009 to 2017 we employ the Propensity Score MatchingDifference in Differences method to estimate the causal effect of ETS . The results suggest that ETS has come into play to a certain extent but the effect attenuates over time . Meanwhile the effect is more pronounced among small scale firms and non state owned firms as well as those pilot regions adopting systems of ex post allowance allocation . Therefore in the process of the national ETS ex post allowance allocation should be widely promoted and more attentions should be given to effectively stimulating the emission reduction capacity of large scale firms and state owned firms . | China s pilot ETS achieves 129.588 million tons carbon emissions reduction. The emission reduction effect of China s ETS attenuates over time. The policy effect is more pronounced among small scale firms and non state owned firms. Ex post allowance allocation promotes corporate emissions reduction. |
S0973082620303100 | Reaching universal access to electricity by 2030 requires a massive deployment of mini grids in rural areas of developing countries . Among the many challenges hindering this process there are the high uncertainties in assessing demand patterns in rural communities the costs of field survey campaigns and the absence of ample and reliable datasets coming from existing projects . This paper tries to address these issues by presenting and discussing a database of load profiles from sixty one off grid mini grids from developing countries worldwide gathered from the literature private developers and fieldworks and reported with technical socio economic and geographical characterization factors . A clustering procedure led to the identification of five archetypal load profile clusters which are presented and analyzed together with their load duration curves . Subsequently the distribution among the clusters of the various characterization factors selected is studied . The proposed approach allows to widen the range of load profiles usually considered and to seek correlations between the load profile shapes the peak power and average energy consumption per connection the number of customers the age of measurement geographical position operator model type of tariff and generation technologies present . This work establishes a first step in the creation of a shared database for load profiles of rural mini grids helping to overcome the lack of available data and difficulties of demand assessment proposing original insights for researchers to understand load patterns and contributing to reduce risks and uncertainties for mini grid developers . | Database of 61 measured load profiles of micro grids in developing countries. Data driven classification by hierarchical clustering identification of four classes. Load models hourly profile and duration curve. Socio economic and technical correlations. Business model geographical position and type of tariff versus technical data |
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