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Abstract This paper proposes a multi-objective, bi-level optimization problem for cooperative planning between renewable energy sources and energy storage units in active distribution systems. The multi-objective upper level serves as the planning issues to determine the sizes, sites, and types of renewable energy sources and energy storage units. The fuzzy multi-objective lower level serves as the operation issues to formulate operation strategy and determine the schedules of energy storage units. By means of bi-level programming, the optimal operation strategy of energy storage units is incorporated into the upper level and optimized with planning issues cooperatively. Meanwhile, to address high-level uncertainties and simultaneously capture the temporal correlation related to renewable energy sources, electric vehicles, and load demands, the validity index of Davies Bouldin is adopted to develop sets of probabilistic scenarios with high quality and diversity. A hierarchical solving strategy based on modified particle swarm optimization is applied to solve the bi-level nonlinear, mixed integer optimization problem. Results and further analyses demonstrate that the proposed planning model and optimization methods have the ability to allocate renewable energy sources and energy storage units effectively for reducing costs, enhancing reliability, and promoting clean energy. Highlights • Bi-level model is proposed to plan renewable energy and energy storage coordinately. • Short-term operation and long-term planning are optimized cooperatively. • Economy, reliability, and environment issues are considered with equal attention. • High-level uncertainties and temporal correlation are addressed simultaneously. • Temporal correlation between renewable energy and load demands are investigated. [ABSTRACT FROM AUTHOR]

Abstract In this paper, a new configuration of distributed energy system (DES), which integrates a district cooling system, is proposed as a new energy-efficient technology to be used in cooling dominated districts. An optimal design approach is developed for DES design and operation scheduling by using the real site measurements of energy demands. A case study on the DES in a high density district, i.e., a university campus in Hong Kong, is performed. The energy and economic performance of the DES, the matching performance of on-site generations and the efficiency of electric chillers are analyzed and compared with that of the centralized energy system (CES). It can be found that the proposed DES is a cost-effective and energy-efficient technology for the regions concerned. The DES contributes to substantial primary energy saving of 9.6% and a significant reduction in the operating cost of 44%. The distributed generations in the DES can match electricity demand very well around the year while the absorption chillers can match cooling demand well in transition months. Compared with the CES, the DES allows electric chillers of larger capacities to be used and to operate at higher part load ratios, resulting in higher energy efficiency in operation. Highlights • A new configuration of DES integrating a district cooling system is proposed. • The DES performance is assessed by comparison with CES based on the real-site measurements. • DES reduces substantial primary energy consumption (9.6%) and operating cost (44%). • Distributed generation can match the electricity demand very well all year round. • The cooling efficiency is improved significantly by using DCS in a high demand density district. [ABSTRACT FROM AUTHOR]

Abstract Two-part, in-situ reactive thermoplastic resin systems for composite wind turbine blades have the potential to lower the blade cost by decreasing cycle times, capital costs of both tooling and equipment, and energy consumption during manufacturing, and enabling recycling at the end of the blade life. This paper describes a techno-economic model used to estimate the cost of a thermoplastic wind turbine blade relative to a baseline thermoset epoxy blade. It was shown that a 61.5-m thermoplastic blade costs 4.7% less than an equivalent epoxy blade. Even though the thermoplastic resin is currently more expensive than epoxy, this cost reduction is primarily driven by the decreased capital costs, faster cycle times, and reduced energy requirements and labor costs. Although thermoplastic technology for resin infusion of wind turbine blades is relatively new, these results suggest that it is economically and technically feasible and warrants further research. Highlights • A thermoplastic wind turbine blade could reduce the manufactured blade cost by 4.7% compared to a thermoset epoxy blade. • An assumed 50% reduction in blade tooling cost for the thermoplastic blade had a significant effect on the cost. • The thermoplastic resin cost would have to increase by over 25% for the thermoplastic blade to be the same price as the epoxy blade. [ABSTRACT FROM AUTHOR]

Abstract This paper investigates different criteria for the design of multi-unit renewable energy (RES) auctions in small markets. The multi-technology RES auctions which are to be implemented in Denmark in 2018 serve as an exemplary case for the assessment. Focus of the analysis is how setting the auction schedule and the auctioned volume per round impacts the auction outcomes, accounting for the particular challenges of small markets. Agent-based modelling of the Danish auctions scheme demonstrates that the Danish RES market provides sufficient competition to auction higher volumes and follow more ambitious expansion goals. Furthermore, with a fixed budget, it is more effective in terms of deployment achieved, to hold fewer auctions with a larger volume. A flexibility mechanism that allows up to 50% of the auction volume to be shifted between auction rounds to accommodate potential large-scale marginal bidders, proves to be a useful tool to increase deployment rates, without negatively affecting bid prices. Furthermore it was shown that at current cost levels, only onshore bidders would be awarded in the envisaged multi-technology scheme. Also, large-scale and multi-project bidders are likely to be most cost competitive - indicating that further measures to maintain diversity could be useful. Highlights • Volume and frequency have to be carefully balanced for RES auctions in small markets. • A too small volume per round can deter especially large scale bidders and lower deployment. • A flexible auction volume is suitable to maximise deployment rates. • Further measures to avoid concentration in the long run are advised in Denmark. • Currently, onshore wind and solar PV are not cost competitive in joint auctions in Denmark. [ABSTRACT FROM AUTHOR]

Abstract Theses on China's low-carbon economy focus on the driving forces of carbon emissions, energy–carbon efficiency, and the carbon–economy nexus. Meanwhile, comprehensive frameworks that assess China's green economy and also analyze its driving forces are lacking. This paper constructs a green productivity index based on the Global Malmquist–Luenberger productivity index to evaluate the development of the low-carbon economy in China. A panel vector auto-regression model is adopted to further analyze the endogenous interactions and dynamic relationships among aspects of the green economy and its influencing factors. Empirical results show that China has seen a balanced development of green economic growth in 2000–2016, achieved in a series of clear stages. To maintain the sustainable growth of the low-carbon economy in the future, China must rely more on technological progress. This research also makes some important discoveries that have not been found in previous studies: the impact of China's industrial structure and energy consumption structure on the green economy are short term, having a duration of impact of approximately four years. Finally, we provide an assessment of provincial green economy development and describe the corresponding policy implications. Graphical abstract Image Highlights • A comprehensive analysis of China's green economy. • A slack-based Global Malmquist–Luenberger index is adopted to calculate the Green Productivity Index in China. • The stage characteristics of green economic development are identified. • A panel vector autoregressive model is used to analyze the interactions among aspects of the environmental economic system. • The findings that the impact duration of energy structure, industry structure, and urbanization on the green economy is about four years. [ABSTRACT FROM AUTHOR]

Abstract This paper discussed the approach for designing an electric powertrain in saving energy while maintaining vehicle power performance and ride comfort. Usually, energy consumption can be improved by motor efficiency optimization. As an innovative layout, electric vehicle with in-wheel motor may suffer additional vibration due to the increase of unsprung weight. Thus, vehicle ride comfort, together with power performance and energy consumption, are considered in the powertrain design. The work is done on two levels. First, requirements for power performance, energy consumption and ride comfort are generated on the vehicle level. Second, the generated requirements are applied onto the in-wheel motor system, which is described by the motor torque, efficiency and weight models. Torque outputs, motor efficiency and lightweight are the corresponding requirements on the subsystem level. Then multi-objective global optimization is carried out on the subsystem level. The Pareto front indicates that lightweight and high efficiency are two conflicting objectives that cannot be compromised on the subsystem level. A constrained energy approach is proposed to determining the final optimal on the vehicle level with the goal of improving vehicle performance and energy consumption. The final solution has a lightweight ratio of 93.5% and motor efficiency of 92%. Highlights • Vehicle energy consumption, acceleration and ride comfort are optimized together. • Vehicle performances are modeled by in-wheel motor powertrain characteristics. • A constrained multi-objective powertrain optimization is built and implemented. • The powertrain optimum solutions are evaluated for better vehicle performances. [ABSTRACT FROM AUTHOR]

Abstract This paper presents the process improvement studies of a combined cycle power plant integrated with a novel gas switching reforming (GSR) process for hydrogen production with integrated CO 2 capture. The overall process is denoted as GSR-CC (gas switching reforming-combined cycle). Five cases are presented in which a systematic approach was adopted to improve the net electrical efficiency of the GSR-CC process. Two cases focus on reducing the number of unit operations and the other three cases focus on heat integration. The net electrical efficiency of the base case GSR-CC process is 45.8% whereas the improved GSR-CC has a net electrical efficiency of 51.1%. The efficiency penalty in the improved GSR-CC process is only 7.2 %-points with respect to the reference case natural gas combined cycle power plant without CO 2 capture, and is less than post-combustion capture methods presented in literature. The CO 2 avoidance in the GSR-CC is more than 95%. GSR-CC also gives a flexibility in the output from the plant in terms of pure H 2 or electricity and the optimal plant configuration is designed to maximize this flexibility. Highlights • Process modelling of the gas switching reforming-combined cycle (GSR-CC) power plant is presented. • Efficiency is improved through power cycle modifications and heat integration. • The best performing configuration shows an energy penalty of only 7.2 %-points. • GSR-CC outperforms post-combustion capture in efficiency and CO 2 avoidance. • GSR-CC also allows for flexibility between electricity and pure H 2 production. [ABSTRACT FROM AUTHOR]

Abstract The paper presents the modeling of a fin-cooled photovoltaic (PV) module, under real operating conditions. A full reconstruction of both the thermal behavior – transient energy balance, loss to the environment and module temperature - and the electrical dynamics for the system allows the efficiency gain assessment, associated with an increased heat exchange with ambient air. Various layouts are considered, in terms of fins mass and its effects on the heat capacity, fins amount and fins geometry. The model accounts for the PV module performances dependence on the (i) operating temperature and (ii) solar irradiance and integrates a section for continuous update of I-V PV characteristics, based on a standard five parameters model and the one-diode approximation. The merge between limit performances - as provided by the manufacturer – and evidences from an extensive experimental campaign for the in-field module characterization, allow a detailed reconstruction of the electric power associated with the module operation and prevent any bias in the model output. The potential of fins in module temperature control and electric efficiency enhancement is assessed and confirms the appeal of such a layout with respect to more consolidated cooling techniques. Highlights • Finned PV module electrical performance and heat exchanges assessment in operation. • I-V curves reconstruction and temperature dependence through a five parameter model. • Five parameter model calibration based on data from experimental campaign. • System optimum design for maximum PV module temperature reduction during operation. • Electric conversion efficiency gain evaluation per achieved temperature reduction. [ABSTRACT FROM AUTHOR]

Abstract Beyond the definition and measurement of energy poverty, which have mainly attracted research interest over the last decades, attention has recently begun to turn to a broader notion of energy vulnerability. So far, this has mostly been approached on a theoretical base, suggesting the incorporation of broader socio-economic aspects into the energy poverty framework. However, the quantitative measurement of energy vulnerability is still an unexplored field of research. In this paper, the "Vulnerability Index" is developed, which, based on stochastic analysis, quantifies the vulnerability of a population to the energy poverty ratio, compared to a reference population. Moreover, Sensitivity Analysis quantifies the particular contribution of various parameters to the problem, by determining their weighting factors. As case study, the vulnerability of Greek mountainous regions with respect to the country level was studied. The results showed that households living in mountainous regions are more vulnerable versus those of the whole country, at 89.7%. It was also found that energy policy should focus on raising incomes of mountainous population and, afterwards, on energy saving measures and reduction of heating cost in mountains. The methodology suggested can address social inequalities of vulnerable population groups, in terms of energy poverty. [ABSTRACT FROM AUTHOR]

Abstract This paper presents a significantly improved optimization model for the planning of the charging infrastructure for electric-drive vehicles, where the optimization objective function is the minimization of overall (installation, maintenance, operation) placement costs of charging stations with regards to a charging technology. The constraints involve the electric power system reliability check, ensuring charging reliability and the required quality of service of the charging infrastructure. In ensuring the charging reliability, at least one candidate location must be selected within the driving range of electric vehicles and suitable charging technologies placed to accommodate the disposable charging times of electric vehicle users for the requested quality of service. The proposed optimization model presents an upgrade of an existing optimization formulation since it includes a power system reliability check based on a DC power flow model. To show the general applicability and significance of the model, a test 10 × 10 grid road network and a standard six-bus test power system are considered. Numeric results illustrate the optimal charging stations placement layout and overall costs placement for different driving ranges and the required quality of service level by including a power system reliability check, to serve both the charging infrastructure investors and electric power system operators. Highlights • Including the electric power system reliability check, to derive an optimal charging stations placement solution. • New constraints in the charging stations placement optimization model, to serve both the investors and network operators. • Lines outage criticality ranking, to provide network operators valuable information for the network expansion planning. [ABSTRACT FROM AUTHOR]

Abstract Integrating thermal desalination systems with vapor compression is an effective way to improve the energy efficiency. This paper investigates a spray-assisted low-temperature desalination system that is integrated with a thermal vapor compression system (SLTD-TVC). A detailed thermodynamic model is judiciously developed based on the principles of heat and mass transfer, heat balance, mass balance, and exergy balance. Applying the model, the energy efficiency of the combined SLTD-TVC process is first evaluated. The production ratio of the combined system is found to be 10–35% higher than that of the conventional SLTD process. Accordingly, an exergy analysis is conducted to quantify the sources of irreversibility within the system. The steam jet ejector is found to be the major source of thermodynamic irreversibility, accounting for more than 40% of the exergy destruction. The overall system efficiency is improved at a lower motive steam pressure, a higher number of operating stages and a medium cooling water flowrate. Finally an economic analysis is carried out, which reveals that the changes of both initial plant cost and operation cost are marginal after the integration of the thermal vapor compression system. Highlights • A novel SLTD-TVC process has been proposed. • A rigorous thermodynamic model has been developed. • Optimal design and operation parameters have been obtained. • Sources of thermodynamic irreversibility have been identified. [ABSTRACT FROM AUTHOR]

Abstract Gasification technologies represent the most viable options of thermochemical processing of solid fuels. They are also characterized by lower emissions and higher efficiency when compared to conventional combustion systems. Particular attention has been paid to underground coal gasification offering the possibility of utilization for energy purposes coal resources otherwise inaccessible for economic or safety reasons. The disadvantage of this process is, however, the difficult control both in terms of technological and environmental aspects. The underground coal gasification process requires investigation of numerous heterogeneous reactions and transport processes, influenced by various process parameters, such as the temperature, type and flow rate of a gasification agent and geological conditions of the georeactor. In the paper a new, alternative way of the determination of kinetics of coal gasification by the Random Pore Model application is proposed. The procedure for determination of model parameters is presented. The structural parameter was estimated on the basis of measurements of char porous structure parameters. The reactivity measurements made for selected Polish coals were applied in determination of kinetic constants. The results of gasification process simulations for determined parameters and Random Pore Model are also given. Highlights • Random Pore Model (RPM) application in modeling of underground coal gasification. • Determination of RPM structural parameter ψ based on coal char porosity measurements. • Determination of RPM kinetic constant for selected Polish coals based on reactivity measurements. • RPM simulation of coal gasification process within the selected range of variables. • Sensitivity analysis for reaction rate changes vs structural parameter ψ variations. [ABSTRACT FROM AUTHOR]

Abstract Fuel economy of hybrid vehicles is affected by their powertrain configurations, powertrain parameters, and energy management strategies. It is most beneficial to optimizing all the three factors simultaneously. However, when the design search space is large, an exhaustive, optimal control strategy, such as dynamic programming (DP), is too computationally expensive. Hence, a faster optimization method with higher computational efficiency and acceptable accuracy is required. Based on the DP approach, an approximate optimization method, called rapid dynamic programming (Rapid-DP), is developed and discussed in this paper. This method effectively reduces the decision-making time (the time can be reduced by a factor of 700, compared to the DP approach) for optimal control. The optimization processes and results are described and then compared with the original DP and PEARS + methods under two different driving cycles: FTP72 and HWFET. In conjunction with particle swarm optimization (PSO), the rapid-DP is leveraged, for the first time, to optimize key powertrain parameters for power split hybrid electric vehicles. Based on two power-split hybrids: Toyota Prius and Prius++, the joint optimization approach is exploited to examine vehicular fuel savings attributed to synergistic parameters optimization and operating-mode increase. The multi-mode configuration with optimal component parameters is demonstrated to be most fuel-efficient, with 6.56% and 3.15% fuel reductions under FTP72 and HWFET cycles, respectively, with respect to the original Prius 2010. Highlights • Dynamics of power split hybrid electric vehicles (PS-HEVs) are modeled. • Rapid dynamic programming (Rapid-DP) is introduced. • A joint energy management and component-parameter optimization is made. • Fuel economy of power split hybrid electric vehicles (PS-HEVs) is optimized. • Synergy of operating-mode increase and system optimization is examined. [ABSTRACT FROM AUTHOR]

Abstract In tropical climates, the energy consumed by ventilation and air conditioning can exceed 50% of the total consumption of a building. Demand for cooling is rising steadily, driven mainly by growing incomes in developing economies, and is expected to also increase with climate change. Tropical, coastal areas with narrow continental shelves are good sites for the implementation of Seawater Air Conditioning (SWAC), a renewable and low CO 2 emission cooling process. This paper presents the existing SWAC projects around the world and gives details on the technology. Data on ocean temperature profiles, ocean bathymetry and world surface temperature are processed with the intent of estimating the world potential of SWAC. The results present the required distance from coast to reach seawater with a temperature of 5 °C or less. This is combined with the potential demand for air conditioning, taking into account surface air temperature and a set SWAC design for cooling from 30 to 20 °C. The pipeline length, seawater depth and capacity factor are then used to estimate the costs of SWAC projects around the world. It is concluded that the locations with the highest potential for SWAC are intertropical islands and some continental locations. Highlights • This renewable source is ideal for tropical coastal areas with narrow continental shelves. • The energy in a m3/s of SWAC can be equivalent to 49 ha of solar PV or 42 MW of wind turbines. • A novel SWAC potential model is developed to identify the most promising sites worldwide. • Capacity factor, pipeline length, depth extraction and cost estimates are presented in detail. • The cheapest SWAC project costs $0.0185/KWh t and is located in Nauru, Pacific Ocean. [ABSTRACT FROM AUTHOR]

High energy prices and the growing concern for “Peak Oil” have put energy analysis, once again, on the front burner. However, before speculating about possible roadmaps regarding our energy future, it would be wise to develop better quantitative analyses. This paper flags the existence of systemic epistemological flaws in the current use of aggregate energy indicators and presents an alternative approach capable of dealing with the issue of multiple dimensions and multiple scales. Starting from a critical appraisal of the aggregate indicator “Economic Energy Intensity” it shows that economic and biophysical variables are often correlated and that their value is determined by characteristics which can only observed across different levels and scales. Complex metabolic systems (systems that use energy to maintain and reproduce themselves) are operating simultaneously at different scales. This implies that changes in the characteristics of parts, defined at the local scale, and changes in the characteristics of the whole, defined at the large scale can only be obtained after establishing a scaling mechanism in the analysis. In order to deal with the issue of scale in energy accounting, we propose to make a distinction between three different categories: (i) primary energy sources (PES) – establishing a link between energy quantities and the associated requirement of biophysical gradients, at the large scale, on the interface black-box/context; (ii) energy carriers (EC) – defining the set of energy inputs required by technical devices for expressing useful functions, at the local scale, within the parts operating inside the black-box; (iii) end uses (EU) the set of functions to be expressed by society across hierarchical levels for reproducing itself. Finally, the paper presents examples of quantitative results obtained using an innovative method of analysis – Multi-Scale Integrated Analysis of Societal and Ecosystem Metabolism (MuSIASEM). We conclude that by using this new accounting method it is possible to generate a better understanding of external and internal constraints determining the desirability and viability of the metabolic pattern of societies. [Copyright &y& Elsevier]

Abstract Phase change material (PCM) have been explored for different applications to increase the energy efficiency and economy. However, the proper PCM selection to meet given requirements generally requires that a compromise is struck between conflicting criteria. This paper attempts to extend multi-criteria decision making (MCDM) method to solve the PCM selection problem. Firstly, the comprehensive appraisal indexes model is established and the subjective and objective weight of the criteria are obtained based on the analytic hierarchy process (AHP) and entropy information method, respectively. Secondly, the optimized combination weight method is adopted to obtain the combination weight. Then, the pre-screened PCMs are ranked using technique for order performance by similarity to an ideal solution (TOPSIS). Finally, the information retrieval is employed to justify the rankings. To demonstrate the applicability of the proposed method, a problem to select the optimal PCM for ground source heat pump (GSHP) integrated with phase change thermal storage (PCTS) system is considered. The result showed that Ba(OH) 2 ·8H 2 O is the best material for the given case and the GSHP integrated with PCTS system has better economic performance compared to the GSHP system, meanwhile, the proposed method is a simple and practical approach in solving the PCM selection problem. Highlights • Establish the comprehensive appraisal indexes model for PCM selection. • Apply the optimized combination weight method to PCM selection. • Examine the ranking goal by information retrieval. • A case study is provided to show the applicability of the proposed method. [ABSTRACT FROM AUTHOR]

Abstract In recent years, with increasing the industrial centers and indulgence in consumption of fossil fuels, the troublesome greenhouse gases such as carbon dioxide and depletion of fossil reservoir has become more prominent. One of the solutions to overcome this problem is utilization of renewable energy resources to generate power and electricity. Hence, a hybrid cycle consisted of biomass/solar is proposed in this paper. The proposed cycle is primarily postulated upon power production via the biomass energy where solar and steam turbine sections are incorporated to increase power output and decrease the CO 2 emission. First, the cycle undergoes through a comprehensive energy, exergy, exergoeconomic, and environmental analysis and the impact of produced power, production cost, and the amount of CO 2 emission of each mentioned sections on the overall produced power, the total cost, and the entire CO 2 emission of the hybrid cycle is discussed and evaluated. In the end, through a parametric assessment, the effect of important thermodynamic parameters on the overall cycle performance is studied. The results indicated that by adding the solar unit to biomass section, the power is increased by 30% and CO 2 emission has decreased by 22%. The capital cost of biomass and steam turbine units compared to the entire cycle are nearly equal as much as 15%, whereas for solar unit the amount of these costs compared to entire cycle is obtained as 71%. Highlights • A novel configuration of renewable hybrid biomass/solar combined cycle is proposed. • System is analyzed in terms of energy, exergy, exergoeconomic and environmental. • A parametric analysis with different approach is conducted. • The proposed cycle has been economically and environmentally justified. [ABSTRACT FROM AUTHOR]

Abstract Pakistan is facing electricity crises owing to lack of integrated energy planning, reliance on imported fuels for power generation, and poor governance. This situation has challenged governments for over a decade to address these crises. However, despite various conformist planning and policy initiatives, the balance between demand and supply of electricity is yet to be achieved. In this study, Long-range Energy Alternatives Planning System (LEAP) is used to develop Pakistan's LEAP modeling framework for the period 2015–2050. Following demand forecast, four supply side scenarios; Reference (REF), Renewable Energy Technologies (RET), Clean Coal Maximum (CCM) and Energy Efficiency and Conservation (EEC) are enacted considering resource potential, techno-economic parameters, and CO 2 emissions. The model results estimate the demand forecast of 1706.3 TWh in 2050, at an annual average growth rate of 8.35%, which is 19 times higher than the base year demand. On the supply side, RET scenario, although capital-intensive earlier in the modeling period, is found to be the sustainable electricity generation path followed by EEC scenario with the lower demand of 1373.2 TWh and minimum Net Present Value (NPV) at an aggregate discount rate of 6%. Conclusion section of the paper provides the recommendations devised from this study results. Highlights • Pakistan's electricity system modeled for the period of 2015–2050 using LEAP tool. • Electricity demand for Pakistan in 2050 has been forecasted as 1706 TWh • Energy efficiency & conservation scenario decreases 20% of electricity demand by 2050. • Four supply side scenarios developed to meet both of these forecasted demands. • Role of energy efficiency improvement & renewable energy integration is significant. [ABSTRACT FROM AUTHOR]

Abstract The rapid growth of electric vehicle (EV) penetration is promoted by fossil fuels depletion, environmental concerns, and energy efficiency initiatives. Battery charging time duration is of the main obstacles to large-scale deployment of this technology. Battery swapping station (BSS) is a new concept to handle this issue in which depleted EV batteries are replaced with a previously full-charged one at a significantly less time duration. To this end, the optimum location of the EV charging among BSSs in the network in addition to the priority charging of the depleted batteries in each BSS should be determined. In this context, the present paper is to perform these tasks optimally and simultaneously. The problem is formulated as a multi-objective programming model in which three non-homogenous objectives are taken into account and solved using the NSGA II algorithm. Two cost-based objectives including minimizing EV batteries charging and power loss cost along with two technical based objectives, comprising voltage profile flattening and network capacity releasing, are considered. Additionally, besides dynamic pricing scheme, a time window method to prevent interruptions in the battery charging is developed. The proposed model is implemented on 33-bus IEEE test system where the results demonstrate its functionality. Highlights • Battery swapping station (BSS) is a new concept to overcome EV charging issues. • The optimum location of the EV charging among the network BSSs is addressed. • A multi-objective model is proposed considering various cost and technical objectives. • The proposed model is solved using the NSGA II algorithm. [ABSTRACT FROM AUTHOR]

Abstract This paper proposes a forecasting framework that employs a seasonal autoregressive integrated moving average model with exogenous variables (main effects) and interaction variables (cross effects) to forecast hourly load demand data. The main effects and cross effects are measured through an iterative process of plotting, interpreting, and testing. Interactions of weather variables and calendar variables, as well as interactions of seasonal patterns and intraday dependencies, are analyzed, tested, and added to the model. The SARIMAX model, which contains only main effects, is compared with the SARIMAX model with interactions, which includes cross effects in addition to the main effects. The proposed SARIMAX model with interactions is shown to produce smaller errors than its competitors. That is, when considering the cross effects, the MAPE falls by 22.2% and the MAE and the RMSE fall by 21.3% and 21.8%, respectively. Thus, including interaction effects of the exogenous variables in the SARIMAX model can potentially improve the model's forecasting performance. Although the model is built using data for a specific region in Japan, the method is completely generic and therefore applicable to any load forecasting problem. Highlights • SARIMA model with exogenous variables and their interactions is employed to forecast load demand. • Interactions of weather, seasonal patterns and intraday dependencies, are considered. • Most of the interactions are useful to improve forecasting.. • The proposed model is shown to produce smaller errors than its competitors. [ABSTRACT FROM AUTHOR]

Abstract The GAS-function methodology is introduced in this paper in order to identify the sustainability objective function for optimisation of multiple interconnected complex steam turbines and utility network (ICSTUN) systems. Also, the complex steam turbine was modelled based on induction machine operation which enhances its performance. The boiler models were identified as the sustainability objective function which was further investigated under given operating constraints for optimisation of the ICSTUN system. The validated results show that relative error between field operation and simulation data were less than 1% on average, which is acceptable for engineering applications. The optimisation results indicate that contrary to previous authors' results and by comparing with actual field operational data information, coal flow rates for total site utility system of this investigated ICSTUN can be significantly reduced. It was therefore concluded that a significant reduction in the coal flow rate amounts is practicable in order to significantly reduce operating costs as well as the environmental and social issues associated with utilising fossil-fuels, while still satisfying the demand-side management objectives for the plant. Highlights • The GAS-function methodology is introduced for analysis of ICSTUN systems. • This model combines basic equations with matrix steam tables for analysis of the system. • The model is practical with the actual energy system based on data acquisition methods. • The results show that induction machine operation enhances the turbine performance. • The results also indicate that fossil-fuel consumption rates can be significantly sustained. [ABSTRACT FROM AUTHOR]

Highlights • The thermodynamic and thermo-economic models of SORC and DORC are built. • The thermodynamic and thermo-economic performances are optimized and compared. • The DORC can increase power output and show better thermo-economic performance. Abstract The goal of this paper is to study and evaluate the thermodynamic and the thermo-economic performance of dual-pressure and single pressure evaporation organic Rankine cycle (DORC and SORC) using isobutane as the working fluid. The effects of the two-stage pressures and the heat source inlet temperature on the system performances have been investigated. Then the performance comparisons between SORC and DORC have been conducted at the optimized condition. Results show that the DORC yields more net power than the SORC when the heat source temperature is between 100 and 177.2 °C, and the net power output gains of the DORC are higher at lower heat source temperature. The DORC no longer has the performance advantage as the heat source temperature is above 177.2 °C. The thermo-economic evaluations show that the optimized electricity production cost (EPC) decreases as the heat source temperature rises. Furthermore, optimized EPC of SORC and DORC are nearly equal at the same heat source temperature. For the heat source temperature of 100–177.2 °C, the DORC can significantly increase the net power output, but the thermo-economic performance of DORC is not reduced by system complexity compared to the SORC. [ABSTRACT FROM AUTHOR]

Highlights • Erythritol and SAT are two of the most concerned materials for M-TES. • The shell-and-tube container is the most versatile type in an M-TES system. • The energy cost of an M-TES system is in a range of 0.02–0.08 € kW h−1. Abstract The transportation of thermal energy is essential for users who are located far away from heat sources. The networks connecting them achieve the goal in efficient heat delivery and reasonable cost, especially for the users with large heat demands. However, it is difficult to satisfy the heat supply of the detached or emergent users with the existing pipelines. Therefore, a promising alternative, called mobilized thermal energy storage (M-TES), was proposed to deliver the heat flexibly without the restriction of networks. In this paper, a review of studies on M-TES is conducted in terms of materials, containers and economic evaluation. The potential candidates of materials, such as sugar alcohols, hydrated salts, alkalies and zeolite are reviewed and compared based on their thermophysical properties, price, advantages and disadvantages. Various containers, including the shell-and-tube, encapsulated, direct-contact, detachable and sorptive types, are discussed from the aspects of configuration, performance and utilization. Furthermore, the studies on the economic evaluation of M-TES systems are summarized and discussed based on the analysis of the economic indicators, including initial cost, operating cost, revenue, subsidy and energy cost. Finally, the challenges and future perspectives for developing M-TES are presented. [ABSTRACT FROM AUTHOR]

Highlights • Modeling the variability of the fuel costs over long term. • Modeling the Multi-Source System taking into account changes in fuel costs. • Limiting the number of starts of the diesel generator to increase its lifecycle. • Increasing the fuel cost can lead to an increase of 18% in the design cost. • Optimization algorithm favors the introduction of renewable sources. Abstract Multi-Source Systems combining renewable energy sources with diesel generators have been widely adopted in isolated sites. The economic and ecological aspects are very important for analyzing and evaluating such systems. In this paper, an optimization approach that includes the former aspects has been proposed. This approach takes into account the changes in the fuel cost over a lifecycle and the minimization of the greenhouse gas emission. The proposed method is based on three main steps. At first, a fuel cost progression model over a period of 40 years has been developed. Second, due to the complexity of such systems and in order to simplify the modeling, meta-models have been extracted by using the Design of Experiments technique. Finally, Single-Objective and Multi-Objective Optimization of the system based on economic and ecological criteria have been performed. The obtained results show that, changes in fuel costs have a significant influence on the sizing of the system. Indeed, the increase in fuel cost can lead to an increase of 18% in the design cost. The best solution on Pareto's curve was found with a reduction rate in the fuel consumption between 30 and 35%. Furthermore, the optimization algorithm favors the introduction of renewable sources. [ABSTRACT FROM AUTHOR]

Highlights • The optimal models designed for standalone and grid connected microgrid system. • Study performed using realistic load profiles, real resource data and prices. • The optimal size attained for microgrid components with the least cost. • Techno-Economics comparison is carried out for lead-acid and lithium-ion battery. • Lithium-ion battery found techno-economically more viable than lead-acid battery. Abstract Microgrids are a beneficial alternative to the conventional generation system that can provide greener, reliable and high quality power with reduced losses, and lower network congestion. However, the performance of renewable energy resource (RER) based generators in a microgrid is hindered by their intermittent nature. The energy storage system plays a key role in overcoming the intermittency of renewable sources by balancing the power demand against variable generation. Energy storage using batteries is accepted as one of the most important and efficient ways for retaining reliable energy supply whilst incorporating RERs into the electricity grid. Lead-acid (LA) batteries have been the most commonly used electrochemical energy storage technology for grid-based applications till date, but many other competing technologies are also being used such as lithium-ion (Li-ion), Sodium-Sulphur and flow batteries. This paper carries out the techno-economic analysis of the battery storage system under different configurations of the microgrid system. The design of an optimal model of standalone as well as grid-connected microgrid systems having PV-wind-diesel and biodiesel energy resources in the presence of Li-ion (LiFeSO 4 type) and LA batteries have been studied. The performance of the two types of batteries has been compared in the proposed microgrid systems considering realistic load profiles, real resource data, and real prices of the components. Load profiles of two rural villages, a business organization and an urban residential building have been used. On the basis of these load profiles and available resources, different microgrid configurations with generation from PV, wind turbine, diesel and biodiesel generators have been considered to study the performances of the batteries. The results include the cost of optimal system configuration under the given scenarios, electricity generation by various generating sources, detail comparison between various components, emissions, and various batteries performance assessment parameters. The study reveals that Li-ion batteries as energy storage are techno-economically more viable compared to LA batteries and they are expected to play a significant role in various applications of future electric power systems. [ABSTRACT FROM AUTHOR]

Skip cycle strategy (SCS) is a stroke volume modulation method leading to reduction in pumping loss through deactivation of engine valves under part-load conditions. Although SCS achieves a significant fuel economy, it increases regulated pollutant emissions such as nitrogen oxide and unburned hydrocarbon in comparison to normal 4-cycle engine operation. This paper investigated normal cycle strategy, skip cycle strategy as well as combination of skip cycle strategy and variable valve timing strategy for a spark-ignition engine using one-dimensional numerical model. The skip cycle engine was modelled at several steady-state operation points and then optimised at best ignition timing providing maximum brake torque at each simulation case. The numerical results obtained for both normal cycle and skip cycle have been validated against the experimental data. After completing the validation of numerical results with engine test bench data for both normal and skip cycle operations, optimisation of intake and exhaust valve timing profiles have been carried out regarding advancing or retarding camshaft relatively to the crankshaft position. In case of SCS and variable valve timing application together, NO x concentration was reduced by 35.1%, 39.4%, 26.8% and HC emission was reduced by 54.9%, 49.3% and 47.4% on average for brake mean effective pressure load levels of 1, 2 and 3 bar respectively at all among engine speed ranges between 1200 and 1800 rpm compared to stand alone SCS strategy. Furthermore, no remarkable additional brake specific fuel consumption was observed for SCS plus variable valve timing strategy compared to stand alone SCS. [ABSTRACT FROM AUTHOR]

Highlights • The input–output model and ecological network analysis (ENA) are integrated. • The control and dependence conditions of economic sectors in China are analyzed. • The key regions and sectors for carbon mitigation of China are identified. Abstract In this paper, multi-regional input–output analysis (MRIO) and ecological network analysis (ENA) are combined to assess carbon flows within China and identify key regions and sectors in the context of spatial heterogeneity for effective carbon mitigation. An interregional carbon network model is established by articulating the directions and magnitudes of carbon flows based on MRIO. ENA is then used to unveil indirect carbon flows and mutual relationships among regions. The results show that the northwest is the largest controller for most regions in China. Most carbon emissions in the rest of China are induced by the east’s final demand and substantial consumption. In addition, at sectoral level, the control and dependence abilities vary by region in China. This study provides an integrated framework to investigate interregional carbon emission structure, identify efficient pathways for coordinated emission mitigation, and reduce global carbon inequality across regions. [ABSTRACT FROM AUTHOR]

The dearth of power generation from energy resources, environmental concerns and ever-increasing demand for electrical energy necessitate optimal economic dispatch with minimum costs and emissions. Due to the confined optimum convergence and non-convexity of realistic scenarios, classical optimization methods are not proficient to handle such problems. Instead, evolutionary optimization methods have gained more attention in recent years. Application of a new proposed double weighted particle swarm optimization (DWPSO) technique in solving non-convex combined emission economic dispatch (CEED) problems with wind power penetration and also solving non-convex multiple fuel option economic dispatch problem has been technologically proposed in this paper. The results on several case study systems are compared with other published methods in literature and confirm the effectiveness of DWPSO against other existing methods. DWPSO successfully reduces the production costs as well as hazardous emissions considering wind power penetration, selects the best fuel types of the generators and adjusts the feasible and optimum settings to allocate load demand to the online generation units in power system. The results demonstrate that using the proposed method can minimize the total generation costs and optimally satisfy the power demands in the grid while the computation performance remains satisfactory even in case of changes in the scale of the network. [ABSTRACT FROM AUTHOR]

The paper analyses the effect of renewable and non-renewable energy consumption as well as the regime type on economic growth in 30 Sub-Saharan African (SSA) countries over the period 1980–2012. Using heterogeneous panel cointegration and panel-based error correction tests, we find long-run relationship between the variables. However, short-run results are not robust, which suggest that energy sector investments are long-term in nature. Specifically, the results show that while both renewable and non-renewable energy have significant positive effect on economic growth, non-renewable energy has a greater growth enhancing effect than renewable energy. A 10% increase in renewable energy consumption is associated with an increase in economic growth by 0.27%, while a 10% increase in non-renewable energy consumption leads to an increase in growth by 2.11% ceteris paribus. Further, the findings of the study show that democratic states experience higher growth rates than autocratic states. [ABSTRACT FROM AUTHOR]

Diesel engines are by far the most common means of propulsion aboard ships. It is estimated that around half of their fuel energy consumption is dissipated as low-grade heat. The organic Rankine cycle technology is a well-established solution for the energy conversion of thermal power from biomass combustion, geothermal reservoirs, and waste heat from industrial processes. However, its economic feasibility has not yet been demonstrated for marine applications. This paper aims at evaluating the potential of using organic Rankine cycle systems for waste heat recovery aboard ships. The suitable vessels and engine heat sources are identified by estimating the total recoverable energy. Different cycle architectures, working fluids, components, and control strategies are analyzed. The economic feasibility and integration on board are also evaluated. A number of research and development areas are identified in order to tackle the challenges limiting a widespread use of this technology in currently operating vessels and new-buildings. The results indicate that organic Rankine cycle units recovering heat from the exhaust gases of engines using low-sulfur fuels could yield fuel savings between 10% and 15%. [ABSTRACT FROM AUTHOR]

This paper investigates the determinants of carbon emissions based on energy consumption, analyzing the data of 30 countries using nuclear energy for the period 1990–2014. Renewable energy and nuclear energy consumption are adopted as determinants, and real coal price and real GDP are used as additive variables. The panel cointegration analysis and Granger causality tests are conducted to investigating the relationship among the variables. First, the panel cointegration test results suggest that long-run equilibrium relationship exists among carbon emissions, renewable energy consumption, and nuclear energy consumption. The results of the long-run cointegrating vector and Granger causality tests indicate that nuclear energy does not contribute to carbon reduction unlike renewable energy. Thus, the development and expansion of renewable, not nuclear, energy are essential to prevent global warming. Though there is a concern that rising energy prices caused by the expansion of renewable energy may impact the economy negatively, our empirical results also imply that renewable energy consumption will promote economic growth. In other words, our evidence shows that using and expanding renewable energy is both economically and ecologically beneficial. [ABSTRACT FROM AUTHOR]

Vehicles travelling in actual urban areas are mostly in idle, low or medium speeds, which reflects engine part-load condition. These regularly visited engine conditions, in reality affect the fuel economy during actual driving. Thus, understanding the characteristics of the actual driving conditions will enable many other benefits besides legislation. This paper presents the development of a preliminary Malaysian urban drive cycle with the inclusion of the engine parameters and characteristics, acquired through an actual urban driving on numerous urban roads in Malaysia that represents the actual consumer’s daily driving experience. The actual engine parameters and its characteristics are integrated into the assessment measures in an attempt to formulate representable drive cycle and fuel consumption data. The initial drive cycle is composed of 17 sequences selected from the actual on-the-road conditions to represent the Malaysian urban driving. The average fuel economy of the established Malaysian urban drive cycle was then measured on a test bench using the same engine from the vehicle. The recorded fuel economy with Malaysian urban drive cycle is 8.5% below the actual Malaysian urban driving which is closer estimation to the actual driving compared to the current in-practice NEDC which shows to be 43.1% below the actual Malaysian urban driving. Thus, Malaysian urban drive cycle is better in representing the Malaysian urban driving conditions compared to the NEDC in terms of the average fuel economy measurements. [ABSTRACT FROM AUTHOR]

Starting from the assumption that household energy use is manifold and intertwined, shaped by many factors which overlap not only at the individual level, but also at a higher level of scales, the paper developed a more integrated approach to its determinants. To assess them and also to find out whether there is a difference between regional-level factors that determine it universally, and those that are context-dependent, the static and dynamic panel analyses were employed in 64 European regions over the period from 2005 to 2013. Our findings suggest that there are common energy consumption determinants and those ones that are dependent on the regions’ level of development. While the sign of the impact of the former is the same across regions, the impact of the latter may differ, depending on the character of the energy policy measures applied. Findings also suggest that energy policy authorities have opportunities to develop and encourage energy efficiency and sustainable use of energy of the household sector by creating regional-specific demand-side energy efficiency programs and measures as well as user practices in relation to technology. [ABSTRACT FROM AUTHOR]

The main goal of this paper is to analyse the efficiency of the plantlet production of Virginia fanpetals, to make economic calculations for their energetic use and to determine the most favourable plant density. According to the experiments, the cost of a healthy Sida plantlet is in the range of 38.4 − 60.6 Euro cents, using the nurse-in-tray technology (NIT). This cost range is much lower than the market prices of the plantlets and the production method is more reliable compared to sowing. In the second year, the dry matter yield originating from Sida plantlets was 10.2 – 11.9 t hectare −1 (ha) without fertilisation in the different planting densities. However, in the longer term, it is recommended to apply organic manure regardless of spacing. The theoretical market value of Sida is generally higher than total unit costs (36 − 60 EUR t − 1 ) in the case of all methods used, except for biogas. The production of Sida can be economical for farmers farming in marginal conditions, using locally available organic manure, producing crops with high heat demand, or involved in beekeeping. [ABSTRACT FROM AUTHOR]

The rapid increase in energy demand and the limited resources of fossil fuel as well as the environmentally damaging effects, drive the world to find new options for sustainable electricity generation, which is represented by renewable energies. Concentrating solar power (CSP) is one of the most promising technologies in the field of electricity generation to tackle this issue with a competitive cost in the future. This paper presents an investigation of the potential of implementation of CSP plants in Libya. The socio-economic context, current energy situation of the country and different types of CSP plants are discussed. Moreover, an assessment of site parameters required for CSP plants including solar resources, land use and topography, water resources and grid connections are investigated in detail. In addition, thermo-economic simulation of a 50 MW parabolic trough power plant is performed. The simulation is conducted based on meteorological data measured by the weather station installed at the Centre for Solar Energy Research and Studies (CSERS) in Tajoura city. The performance results are compared with the reference plant Andasol-1 in Spain. Even though the proposed plant is located on the North coast where solar resources are at their minimum compared with other regions of the country, the outcome of the study proves that Libya is not only suitable but it can be economically competitive in the implementation of CSP technology. [ABSTRACT FROM AUTHOR]

In the prevailing scenario, the aberrant use of conventional fuels and the impact of greenhouse gases on the environment have leveraged the research efforts into renewable energy production from organic resources and waste. The global energy demand is high and most of the energy is produced from fossil resources. Recent studies refer the anaerobic digestion (AD) as alternative and efficient technology which combines biofuel production and sustainable waste management. There are different technological trends in biogas industry in order to enhance the production and the quality of biogas. Nevertheless, the success of AD for further investments will rise from the low cost of feedstocks availability and the wide variety of usable forms of biogas (heating, electricity and fuel). Biogas, a combination of two-thirds of methane (CH 4 ) and the rest is mostly carbon dioxide (CO 2 ) with traces of hydrogen sulfide. The spent slurry from the produced biogas can be enriched to be utilized as manure for agricultural crop, promoting sustainable biomass production in the world. Biogas can be utilized to produce centralized or distributed power supply in rural and urban areas and are considered to be cost beneficial. The aim of this review paper is to analyze various feedstocks, which are widely used all over the world. The working operations of anaerobic digestion process, current trends along with its merits and demerits are also discussed in order to draw more research and development towards producing a sustainable environment. [ABSTRACT FROM AUTHOR]

In the past decades, solar heat for industrial processes (SHIP) have been rapidly developed and applied, and also getting more and more attention all over the world. China is the largest energy consumer with industry accounting for almost 70% of its total energy consumption. Low- and medium-temperature heat takes up 45% of process heat, covering 50–70% of industrial energy consumption, which provides a favorable condition for solar application in industrial processes. China has built developed some demonstration projects to make industrial processes well integrated with solar heating systems. This paper briefly summarizes the status of China's energy consumption, integration of SHIP, as well as available matching solar technologies. Ten typical industrial sectors are selected to specifically describe their potential of SHIP. Moreover, 26 SHIP cases covering the selected 10 sectors are presented by field researches, with capacity of energy saving and emission reduction previously investigated according to their own proportion of SHIP. The potential of SHIP in the 10 sectors are further predicted by optimistically and conservatively making their proportion in SHIP 5.5% and 2% respectively during the period of 2016–2020. The results show that at least 39.40 million tons of coal equivalent and 98.22 million tons of CO 2 emission is expected to be reduced in 2020 in China's all industrial sectors although solar can meet different proportions of heat demand in different industrial sectors. [ABSTRACT FROM AUTHOR]

Solar simulators are used to test components and systems under controlled and repeatable conditions, often in locations with unsuitable insolation for outdoor testing. The growth in renewable energy generation has led to an increased need to develop, manufacture and test components and subsystems for solar thermal, photovoltaic (PV), and concentrating optics for both thermal and electrical solar applications. At the heart of any solar simulator is the light source itself. This paper reviews the light sources available for both low and high-flux solar simulators used for thermal applications. Criteria considered include a comparison of the lamp wavelength spectrum with the solar spectrum, lamp intensity, cost, stability, durability, and any hazards associated with use. Four main lamp types are discussed in detail, namely argon arc, the metal halide, tungsten halogen lamp, and xenon arc lamps. In addition to describing the characteristics of each lamp type, the popularity of usage of each type over time is also indicated. This is followed by guidelines for selecting a suitable lamp, depending on the requirements of the user and the criteria applied for selection. The appropriate international standards are also addressed and discussed. The review shows that metal halide and xenon arc lamps predominate, since both provide a good spectral match to the solar output. The xenon lamp provides a more intense and stable output, but has the disadvantages of being a high-pressure component, requiring infrared filtering, and the need of a more complex and expensive power supply. As a result, many new solar simulators prefer metal halide lamps. [ABSTRACT FROM AUTHOR]

Grid electricity generation in Nigeria has been unstable for a long time now. With respect to her continued dependence on oil and gas and seasonal variations on water level for hydropower, immediate reliable and steady electricity generation in the country is not guaranteed. Incorporating alternative source of energy like solar is a solution. Solar Chimney technology is not yet technically and economically mature, as investment on it is still low, thereby posing more financial risks at least at the megawatt capacity. Photovoltaic and Solar Thermal technologies are technically and economically more established, but they can only ensure 24-h power supply with the aid of energy storage systems. Solar thermal value addition is on its propensity for thermal energy storage and hybridization with liquid fuels at commercial capacity. Hence, due to technology advancement and the country's high direct normal irradiation potential, concentrating solar power is the more suitable solar power technology for commercial electricity generation in Nigeria. In this paper, concentrating solar power technologies are analysed under operational, environmental and social conditions in Nigeria using data from desktop survey to determine the most suitable technology for solar thermal electric power plant. It is observed that the technical maturity of parabolic trough concentrator distinguishes it for preference to all other technologies and would exert moderate pressure on land requirement even though, it is the most expensive and water demanding technology. In terms of unit cost of electricity and water usage capabilities, parabolic dish concentrator is least expensive and uses least water but lacks proven commercial application. Solar tower is technically simpler and possesses better thermodynamic properties than the rest but its low installed capacity increases its financing risk. Hence, the trough system is the most suitable for immediate and medium term projects given its proven technology maturity and flexible financing mechanism. [ABSTRACT FROM AUTHOR]

The objective of this study is to trace and quantify the sources of rebound effect for different energy sources in China. This paper decomposes the economy-wide rebound effect into 135 production sector-level rebound effects and five final demand components. The sector-level rebound is further decomposed into output effect and substitution effect. A two-stage decomposition method and a static computable general equilibrium model are developed to achieve this. Five types of energy-specific efficiency improvements are introduced, respectively, in all the production sectors. Results show that improving efficiency of using coal leads to the smallest macro-level rebound. For rebound decomposition, four findings are generalized. First, final consumption shows larger impact on the rebound of secondary energy sources than on primary energy sources. Second, production sectors that are big user of the efficiency-exposed energy source are expected to be key rebound contributor. Third, energy-producing sectors make negative rebound contribution. Results also show that, substitution effect is the predominant mechanism that triggers sector-level rebound. Policy implications are also discussed. [ABSTRACT FROM AUTHOR]

Abstract: The purpose of this paper is to demonstrate the relationships between sustainable building design and occupant well-being. It starts with a definition of sustainable design and well-being, and focuses on the relationships between energy performance and occupant feedback. Methodologically it draws on detailed monitoring and surveys of 12 case study office buildings in the UK and India, and the paper uses the data to explore whether energy use and associated CO2 emissions are correlated to occupant satisfaction and comfort. The results demonstrate that increased energy use in the case study buildings is associated with increased mechanisation (e.g. centralised air conditioning) and reduced occupant control. This reduced control in turn is shown to relate to reduced occupant comfort and satisfaction. Finally, the paper reveals that the reported health conditions of occupants correlates strongly with their levels of satisfaction. The overall conclusion is that energy use in typical office buildings is inversely correlated with the well-being of the occupants: more energy use does not improve well-being. [Copyright &y& Elsevier]

Abstract: China''s total energy consumption, according to the official data, decreased impressively during 1997–1998 and increased sharply during 2003–2007, which in turn resulted in energy intensity fluctuation. Many literatures explained this “unusual phenomenon” from the perspectives of technical change, economic structure shifting and statistical data quality. They measured aggregate energy in thermal units by using linear summation approaches. In this paper, from the perspectives of heterogeneity and imperfect substitutability among diverse energy types, we further examine China''s aggregate energy consumption by using Divisia (Sato-Vartia) approach. The results show that China''s aggregate energy consumption and intensity fluctuated slightly less than values calculated by using conventional linear approaches, and the “unusual phenomenon” is partly explained. It also implies that China''s energy intensity changes in 2006–2007 are slightly more optimistic than those officially reported, and the official communiqué of provincial energy intensity reduction achievements are partly bias. Some provincial achievement are underestimated or overestimated on some provinces. Our empirical results are also helpful to further research, such as energy–economic modeling, energy price elasticity, and elasticity of substitution among capital–labor–energy–material (KLEM). The difficulties or defects when using Divisia approach are also discussed in this paper. [Copyright &y& Elsevier]

Abstract: The global cheese-making industry processes approximately one quarter of total raw milk production to create a variety of consumer cheeses, and cheese processing can be very energy-intensive. Characterizing energy usage in existing cheese markets and plants can provide baseline information to allow comparisons of energy performance of individual plants and systems. In this paper, we analyzed energy data compiled through extensive literature reviews on cheese-making across various countries and regions. The study has found that the magnitudes of average final energy intensity exhibited significant variations, ranging from 4.9 to 8.9MJ per kg cheese across a few countries. In addition, the final energy intensity of individual plants exhibited even more significant variations, ranging from 1.8 to 68.2MJ per kg of cheese from the countries in this study. These significant differences have indicated large potential energy savings'' opportunities in the sector. The paper also indicates that there are positive association between implementation of energy measures and the decreasing trends of specific energy consumption over time, and suggests that developing and promulgating an energy-benchmarking framework including a process step approach and efficiency measures should be recommended for evaluating energy performance and improving energy efficiency in cheese-making industry. [Copyright &y& Elsevier]

Abstract: Thermally activated building systems (TABS) integrate the building structure as energy storage, and have proofed to be energy efficient and economic viable for the heating and cooling of buildings. Although TABS are increasingly used, in many cases control has remained an issue to be improved. In this paper, a method is outlined allowing for automated control of TABS in intermittent operation with pulse width modulation (PWM). This method represents one part of a TABS control solution with automatic switching between cooling and heating modes for variable comfort criteria which was published before. A first pulse width modulation control solution is derived based on a simple 1st order model of TABS. Then a second, even simpler solution is given that significantly reduces the tuning effort. Finally, the paper outlines a pulse width modulation control procedure and gives two application examples of the PWM control carried out in a laboratory test room. [Copyright &y& Elsevier]

Abstract: India''s energy challenges are multi-pronged. They are manifested through growing demand for modern energy carriers, a fossil fuel dominated energy system facing a severe resource crunch, the need for creating access to quality energy for the large section of deprived population, vulnerable energy security, local and global pollution regimes and the need for sustaining economic development. Renewable energy is considered as one of the most promising alternatives. Recognizing this potential, India has been implementing one of the largest renewable energy programmes in the world. Among the renewable energy technologies, bioenergy has a large diverse portfolio including efficient biomass stoves, biogas, biomass combustion and gasification and process heat and liquid fuels. India has also formulated and implemented a number of innovative policies and programmes to promote bioenergy technologies. However, according to some preliminary studies, the success rate is marginal compared to the potential available. This limited success is a clear indicator of the need for a serious reassessment of the bioenergy programme. Further, a realization of the need for adopting a sustainable energy path to address the above challenges will be the guiding force in this reassessment. In this paper an attempt is made to consider the potential of bioenergy to meet the rural energy needs: (1) biomass combustion and gasification for electricity; (2) biomethanation for cooking energy (gas) and electricity; and (3) efficient wood-burning devices for cooking. The paper focuses on analysing the effectiveness of bioenergy in creating this rural energy access and its sustainability in the long run through assessing: the demand for bioenergy and potential that could be created; technologies, status of commercialization and technology transfer and dissemination in India; economic and environmental performance and impacts; bioenergy policies, regulatory measures and barrier analysis. The whole assessment aims at presenting bioenergy as an integral part of a sustainable energy strategy for India. The results show that bioenergy technology (BET) alternatives compare favourably with the conventional ones. The cost comparisons show that the unit costs of BET alternatives are in the range of 15–187% of the conventional alternatives. The climate change benefits in terms of carbon emission reductions are to the tune of 110T C per year provided the available potential of BETs are utilized. [Copyright &y& Elsevier]

Abstract: There are many kinds of methods to estimate the energy requirement or fuel consumption in the optimal design and minimize the life cost of a building. The bin method is one of the most popular ways to estimate the energy performance of a building, which is based on the hourly-based outdoor dry-bulb temperatures of all days in a whole year. There is lack of information about the bin weather data in China. In this paper, the ambient temperature bin data for 26 cities in China are generated. Based on the method used in this paper, the bin data can be calculated with the long-term daily weather record or TMY weather data, the deviation between them is acceptable. The bin data given in this paper may have the positive impact on building energy conservation in China. [Copyright &y& Elsevier]

Abstract: The present paper deals with the energy performance, energy classification and rating and the global environmental quality of school buildings. A new energy classification technique based on intelligent clustering methodologies is proposed. Energy rating of school buildings provides specific information on their energy consumption and efficiency relative to the other buildings of similar nature and permits a better planning of interventions to improve its energy performance. The overall work reported in the present paper, is carried out in three phases. During the first phase energy consumption data have been collected through energy surveys performed in 320 schools in Greece. In the second phase an innovative energy rating scheme based on fuzzy clustering techniques has been developed, while in the third phase, 10 schools have been selected and detailed measurements of their energy efficiency and performance as well as of the global environmental quality have been performed using a specific experimental protocol. The proposed energy rating method has been applied while the main environmental and energy problems have been identified. The potential for energy and environmental improvements has been assessed. [Copyright &y& Elsevier]

In the last decade, the significant level of carbon emission in the atmosphere has increased the temperature of the Earth by 50% compared to the pre-industrial period. In recent years, considering renewable energy sources integrated with different energy systems such as cooling, heating, and power has become widespread around the globe as the ambition is to produce sustainable and clean energy. However, as the conventional methods for energy generation are highly reliable, their usage for supplying energy demands is inevitable. Therefore, in such renewable-based generation systems, the issues arising from uncertainties are the main challenges to the high penetration of these technologies. In this paper, the aim is to appraise such challenges in a multi-energy combined heat and power (CHP)-based microgrid integrated with power-to-gas (P-2-G) technology. In the proposed system, the downside risk constraint (DRC) approach as an effective risk management method is considered for risk assessment. The proposed model is a mixed integer linear program that is modeled as a multi-objective risk-based problem, for which the epsilon constraints method is used to achieve the optimal solutions for the objectives. According to the results, using P-2-G as an environmentally friendly tool can reduce approximately 55% of the emission cost. Further, the operating cost is increased nearly 13% to obtain a zero-risk condition for optimal management. [Display omitted] • Risk-constrained emission reduction and flexibility improvement in the fossil-fueled CHP-based multi-vector system. • A stochastic-based risk-aware multi-objective optimization framework with iterative solution mechanism. • Risk analysis with downside risk constraint (DRC) approach for the multi-vector uncertainties. [ABSTRACT FROM AUTHOR]

With the deregulation of electricity market and the penetration of renewable energy, microgrid system operators may encounter more difficulties in operation management when facing complex economic, technological, and political uncertainties. In this paper, a robust cost-risk tradeoff model is developed for day-ahead schedule optimization in residential microgrid system under uncertainties. This method is an integration of inexact two-stage stochastic programming and worst-case conditional value-at-risk theory, and could handle uncertainties with inexact or partly known probability distribution information. Besides, by introducing the financial risk measurement, it could also hedge against the worst-case scenario caused by multiple independent uncertainties. The proposed model was applied to a hypothetical residential microgrid system with combined heat and power generation for obtaining optimal day-ahead schedule strategies under variable conditions with respect to renewable energy generation, power demand, and electricity market price. The obtained solutions demonstrate that the proposed model could reflect better tradeoff information between economic operation and stable performance according to different risk-aversion attitudes. In general, more conservative risk attitude would be coupled with higher system cost, which implies higher system stability is at the expense of the economic costs. The developed robust cost-risk tradeoff method would be expected to have a potential for wide applications. [ABSTRACT FROM AUTHOR]

Energy has been the major input for the national economies. While fossil-based energy resources are diminishing, researchers are focusing on alternative fuels and various technology options for conversion, distribution, and end user's operating environment processes. As the search for the alternative pathways for the “sustainable economy” idea continues, management factor is getting considerably important within each phase of energy generation and consumption. In this paper, we employ a hybrid multi-criteria decision-making methodology to evaluate the energy management performance of selected nine countries with a focus on Turkey with respect to a number of criteria. The hybrid approach integrates three methods, viz. Analytical Hierarchy Process, Multi-Criteria Optimization and Compromise Solution, and Technique for Order Preference by Similarity to Ideal Solution. It enables decision-makers assess multiple alternatives within an analytic framework while considering multiple criteria simultaneously. We perform our analysis for each year between 2001 and 2016. The results show that, with its fast-growing population, dynamic economy, and huge energy saving potential, Turkey displays a low profile compared to the other countries in our scope. Our results can be encompassed by in-depth analyses and long-term plans to shift the country's energy technology selection strategies to more efficient, cost-effective and cleaner options. [ABSTRACT FROM AUTHOR]