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Abstract: This paper presents a comparative study of two energy system analysis models both designed for the purpose of analysing electricity systems with a substantial share of fluctuating renewable energy. The first model (EnergyPLAN) has been designed for national and regional analyses. It has been used in the design of strategies for integration of wind power and other fluctuating renewable energy sources into the future energy supply. The model has been used for investigating new operation strategies and investments in flexibility in order to utilize wind power and avoid excess production. The other model (H2RES) has been designed for simulating the integration of renewable sources and hydrogen into island energy systems. The H2RES model can use wind, solar and hydro as renewable energy sources and diesel blocks as backup. The latest version of the H2RES model has an integrated grid connection with the mainland. The H2RES model was tested on the power system of Porto Santo Island, Madeira, Portugal, Corvo and Graciosa Islands, Azores Islands, Portugal and Sal Island, Cape Verde. This paper presents the results of using the two different models on the same case, the island of Mljet, Croatia. The paper compares methodologies and results with the purpose of identifying mutual benefits and improvements of both models. [Copyright &y& Elsevier]

Abstract: This paper discusses the perspective of renewable energy (wind, solar, wave and biomass) in the making of strategies for a sustainable development. Such strategies typically involve three major technological changes: energy savings on the demand side, efficiency improvements in the energy production, and replacement of fossil fuels by various sources of renewable energy. Consequently, large-scale renewable energy implementation plans must include strategies for integrating renewable sources in coherent energy systems influenced by energy savings and efficiency measures. Based on the case of Denmark, this paper discusses the problems and perspectives of converting present energy systems into a 100% renewable energy system. The conclusion is that such development is possible. The necessary renewable energy sources are present, and if further technological improvements of the energy system are achieved the renewable energy system can be created. Especially technologies of converting the transportation sector and the introduction of flexible energy system technologies are crucial. [Copyright &y& Elsevier]

COVID-19 brings new challenges to addressing climate change and achieving the goal of environmental sustainability. This paper examines how the COVID-19 pandemic affects transmission of returns spillovers among green finance, carbon market and renewable & non-renewable energy in China. We evaluate the dynamic and directional risk connectedness across time and at various frequency bands using Diebold and Yilmaz and Baruník and Křehlík approaches. First, the total spillover effects increase significantly when the COVID-19 outbreak. Second, the carbon price fluctuations are mainly influenced by non-renewable energy. Third, the spillover effect is mainly acted in the short term, meaning that it is strongly influenced by investor sentiment in the short term. Fourth, non-renewable energy and carbon markets are the main net recipients and can be used as hedge assets. Finally, the total spillover is time-varying that is affected by the unexpected crisis. The findings will help policymakers and environmental investors to develop policy measures and portfolios that are appropriate for different frequency domains. • Time-frequency connectedness among green finance, carbon and energy is tested. • Spillovers increase at the onset of the COVID-19 and mainly acted in the short-term. • The carbon price fluctuations are mainly influenced by non-renewable energy. • Non-renewable energy and carbon markets are the major net recipients. • The total spillover is time-varying affected by the unexpected crisis. [ABSTRACT FROM AUTHOR]

As the penetration rate of renewable energy continues to increase, reliability confidence capacity, an important indicator for measuring the contribution of power sources to the power system, has received widespread attention in the planning and design of power systems. However, reliability confidence capacity can no longer be fully applicable to the planning and design of new power systems with renewable energy as the core feature. Therefore, this paper proposes the concept of renewable energy flexibility confidence capacity and constructs a mathematical model. Firstly, based on the consideration of flexibility, a renewable energy flexible confidence capacity evaluation model is established using the sequential Monte Carlo method. Secondly, the changes and reasons for various flexibility indicators in the system under different energy penetration rates are analyzed. Then, the differences and reasons for renewable energy flexibility confidence capacity evaluation results under different energy penetration rates are compared and analyzed. Based on the weights of various flexibility indicators, the renewable energy flexibility confidence capacity under different energy penetration rates is comprehensively evaluated. Finally, the actual power grid data of a certain region in Xinjiang, China is simulated and analyzed. The results of the case study verify the rationality and effectiveness of the proposed method. • System balancing mechanism under different energy penetration rates is analyzed. • A renewable energy flexibility confidence capacity index is proposed. • Evaluation method for renewable energy flexibility confidence capacity is proposed. [ABSTRACT FROM AUTHOR]

This paper develops a thermodynamic model for the regenerative Brayton cycle that uses monochlorobiphenyl waste as fuel in a combustion chamber to power a gas turbine. The regenerator increases the air temperature entering the combustion chamber to react with monochlorobiphenyl wastes to produce a higher turbine inlet temperature. The pressure ratio and turbine inlet temperature can negatively or positively affect power plants' thermal efficiency. Thus, different pressure ratios and turbine inlet temperatures are used to calculate the overall thermal efficiency. A stoichiometric reaction-based gas composition model is used to determine the combustion gas composition at the combustion chamber exit and to calculate the heat capacity of air and combustion gases as a function of temperature. The exergy analysis of the proposed power plant is presented to determine the effect of the pressure ratio on the exergy efficiency of the turbine, compressor, and regenerator. According to the results, an increase in pressure ratio increases cycle thermal efficiency and turbine inlet temperature when using a regenerator, whereas the temperatures decrease when not using a regenerator. The Brayton cycle with a regenerator increases thermal efficiency from 30% to 100% for a pressure ratio of 6–30. This contrasts with the Brayton cycle without a regenerator. In addition, for the regenerative Brayton cycle, the turbine inlet temperature rises from 1050 K to 1200 K as the pressure ratio rises from 1 to 30. In the absence of the regenerator, however, this variation's trend is in the opposite direction. Furthermore, the results show that an increase in pressure ratio will increase the exergy efficiency of the compressor and regenerator, while a decrease will occur in the exergy efficiency of the turbine. Findings indicate that the regenerator has the highest exergy efficiency at a pressure ratio higher than five, followed by turbine and compressor exergy efficiency. [Display omitted] • Increase in pressure ratio, improves regenerator and compressor exergy efficiency. • Turbine efficiency increases system efficiency in "with regenerative" mode. • In "no regeneration" mode, boosting the pressure ratio improves thermal efficiency. • In "with regeneration" mode, turbine intake temperature decrease with pressure ratio. [ABSTRACT FROM AUTHOR]

Increased levels of renewable energy penetration have created new congestion patterns in recent years. Since the grid is not designed for the new patterns, the operators may need to curtail renewable energy to maintain transmission flows within acceptable limits. Transmission line impedance control, using flexible ac transmission system (FACTS) devices, has been proposed as an approach to relieve congestion in transmission systems and enhance renewable energy utilization. In this paper, we conduct a comprehensive study to provide insights on FACTS implementation's impact on renewable energy integration and carbon emission reduction. The study considers variations in renewable energy penetration level, system loading patterns, location of renewable generation, and location of FACTS devices. Furthermore, generation mix data from prominent regional transmission organizations (RTO) are used to achieve more realistic results. Simulations studies are carried out on a modified RTS-96 system with a two-stage stochastic unit commitment model. The results show that, even though impedance control is effective in cost reduction, it has limitations in facilitating renewable energy integration in systems with prominent cheap fossil fuel power plants. • Impedance control reduces cost but may not always enhance renewable integration. • Generation mix highly influences the effectiveness of FACTS in emission reduction. • For high levels of renewable penetration, transmission expansion is necessary. [ABSTRACT FROM AUTHOR]

The Norwegian Agrarian Association has the ambition to reduce greenhouse gas (GHG) emissions by 4–6 million tons of carbon dioxide equivalents (CO 2 -eq) by 2030 in the agricultural sector. As a part of this, 10–25% is expected to come from substituting fossil fuels with renewable energy sources. This paper focuses on the effects of phasing-out fossil fuel consumption in on-field tractor operations with electrification by introducing battery-electric and/or fuel cell tractors and on-site renewable energy generation and storage. The results show that electrification of on-field tractor operations can be a techno-economically feasible pathway to reduce tractor energy-use-related CO 2 emissions in the agricultural sector. Annual CO 2 emissions are observed to reduce by 69% in 2030 and 97% in 2050. However, the CO 2 reduction potential can vary significantly based on the farm type. In this regard, the analysis revealed high sensitivity to manufacturing costs of zero-emission tractors (ZETs), which in combination with a low utilization rate can render the investment to ZETs unprofitable. Moreover, electrification increases electricity consumption, especially peak electricity demand in the agricultural sector. This effect can be reduced with on-site renewable energy generation and energy storage systems. • TIMES-models with differing spatial and temporal resolutions are soft-linked. • The long-term effects of electrification in the agricultural sector in Norway are analysed. • Electrification of on-field tractor operations can reduce energy-use related CO 2 emissions. • Adverse effects of electrification can be mitigated with distributed energy generation. [ABSTRACT FROM AUTHOR]

This paper focuses on a support management system for the management and operation planning of a microgrid by the new electricity market agent, the microgrid aggregator. The aggregator performs the management of microturbines, wind and photovoltaic systems, energy storage, electric vehicles, and usage of energy aiming at having the best participation in the market. Nowadays, the electricity market participation entails making decisions aided by a support and information system, which is an important part of a microgrid support management system. The microgrid support management system developed in this paper has a formulation based on a stochastic mixed-integer linear programming problem that depends on knowledge of the stochastic processes that describe the uncertain parameters. A set of plausible scenarios computed by Kernel Density Estimation sets the characterization of the random variables. But as commonly happen, a scenario reduction is necessary to avoid the need to have significant computational requirements due to the high degree of uncertainty. The scenario reduction carried out is a two-tier procedure, following a K-means clustering technique and a fast backward scenario reduction method. The case studies reveal the performance of the microgrid and validate the methodology basis conceived for the microgrid support management system. • Microgrid support management system in the scope of electricity markets. • Stochastic programming problem to consider the uncertainty in the microgrid. • Two-tier scenario reduction capable of reducing the computation time. • Integration of electric vehicles and the consideration of demand response. • Case studies describing the performance of the microgrid. [ABSTRACT FROM AUTHOR]

Since the overall energy consumption of residential buildings has significantly increased over the recent decades many technologies have been established to reduce the power consumption of households significantly and to use energy efficiently. In general, thermal energy for heating or cooling devices of domestic appliances is generated decentralized by the respective device and not in one central location of the building. This paper introduces a novel system design, where domestic appliances like the washing machine, dishwasher, condensing dryer, refrigerator and freezer are thermally interconnected to the heating and ventilation system in a low-energy building via the “energiBUS” – not only in terms of warm water, but also for cooling tasks. The integrated system concept is presented and load profiles are analyzed to discuss the functionality of the system and the energetic flows. The system benefits from the replacement of power consuming heating and cooling devices of the domestic appliances and the synchronized operation of the heat pump due to an additional hot and a cold water storage. In comparison to a system without the “energiBUS”, the overall power consumption of a four-person family home in passive house design is reduced by about 200 kWh/a without the improved heat pump synchronization. [ABSTRACT FROM AUTHOR]

Fossil fuels cannot provide all the required energy in future due to their exhaustibility. Their utilization also leads to huge environmental problems. Therefore, it is vital to find a new inexhaustible and clean source of energy which could be easily stored and transported. Hydrogen produced by renewable energy sources has all the above mentioned advantages. There are many hydrogen production methods which could be coupled with renewable energy sources. Among them, electrolysis process is the most mature one. In this paper, a review is performed on different methods of coupling electrolyzer systems with different renewable energy sources, including solar energy, wind energy, geothermal energy, ocean thermal energy conversion system and hydroelectric energy. The focus of this study is on how these systems can be integrated and which one has the highest total efficiency. Finally, cost of hydrogen production by different energy sources is compared. [ABSTRACT FROM AUTHOR]

In this paper, a review on solar drying is presented. The review comprises the main components, classifications and affecting parameters. Advantages, disadvantages and limitations of such technology are also investigated. That said, solar dryers are assessed according to three key-elements: way of air movement (passive and active), mode of transferring heat (direct and indirect, hybrid and mixed) and type of drying chamber (cabinet, greenhouse and tent). Moreover, economic and environmental studies are performed for the Lebanese case in order to assess the Payback Period (PP) and the amount of CO 2 reduction. The examined parameters are the percentage of time where solar dryer is utilized (Pr), the mass of dried food and food type. Results show that for Pr equals to 0.6, when drying 120 kg of carrots using solar dryer the amount of Saved Money (SM) is 780 $/month, PP is 10 months and the amount of CO2 emissions decreases by 6400 kg/month. [ABSTRACT FROM AUTHOR]

Bangladesh, currently a low middle-income economy aspires to become a high middle income country by 2021. To achieve such aspiration, the country will have to ensure adequate power supply for its fast growing economy. Bangladesh lacks energy resources for power generation. This paper explores some of the power supply scenarios with special focus on power imports and higher use of renewables. Using the technology rich, least cost optimization model 'The Integrated MARKAL-EFOM System (TIMES)', the authors developed four possible future power supply scenarios for Bangladesh. These scenarios include an energy security framework (based on the Power System Master Plan (PSMP) 2016 report), a high power import scenario, a scenario with higher use of renewables and a combined high power import - high renewables development scenario. The analysis indicates that the present energy security framework ensures energy security with diversifying fuels used for power generation, however, scenarios with high power imports and a high share of renewables (including the combined scenario) bring down the cost of supplying power along with a reduction in expensive fossil fuel imports while maintaining energy security as fuel sources for power generation still remain diversified. [ABSTRACT FROM AUTHOR]

This paper presents an economic assessment of large power (from tens to hundreds kWp) PV irrigation systems in the ECOWAS region, evaluating the economic feasibility of substituting diesel-powered and grid-powered systems with PV ones. Seven countries from the ECOWAS region were considered and two irrigation operating modes were compared (pumping to a water tank or at constant pressure). Net Present Cost (NPC) values are in the 0.33–41.5 × 10 5 $ range, Internal Rate of Return (IRR) values are in the 8–47% range and Payback Period (PBP) values are in the 2.1–10 years range. The economic savings in terms of Levelized Cost of Energy, LCOE, were also evaluated. LCOE for PV irrigation systems are in the 4.5–17.4 $cents/kWh range, which represent percentage savings of 30–84% if compared to diesel-powered and grid-powered systems. [ABSTRACT FROM AUTHOR]

The Liquid Solar Fuel (LSF) concept aims to provide renewable-energy-based fuels like synthetic Diesel and Kerosene for long-distance transport via trucks, ships and airplanes and for remote machinery. The purpose of this paper is to present a preliminary design and performance model of a small scale plant with a rated production capacity of 100 barrels per day. First technical and economic performance estimates suggest that an achievable process efficiency around 50% and a product cost of ca. 1 US$/liter for large scale units in the medium term future can be attractive when compared to similar processes like power-to-liquid or biomass-to-liquid. A key attribute of the LSF concept is to maximize efficiency of all physical and chemical processes involved by continuous full-load operation of the synthesis process avoiding any transients, and by integrating and recycling all involved energy and material flows. How to achieve this in an effective way in spite of mainly using variable renewable energy from sunshine and wind for power supply is a key finding of the analysis, significantly reducing the need for major storage facilities for hydrogen and other involved substances. A major implication of the study is that carbon-free production of synthetic liquid hydrocarbon fuels is possible with present state-of-the-art technologies and can be efficient and affordable under appropriate frame conditions that exist in many parts of the world. The analysis has been made in the frame of internal activities of the Department of Systems Analysis and Technology Assessment at the German Aerospace Center (DLR) in Stuttgart, Germany, since 2008, and had the goal to identify sustainable solutions for future long-distance transport fuels. The model analysis provides technical and economic performance estimates of a first prototype. [ABSTRACT FROM AUTHOR]

This paper proposes a methodology for sizing stand-alone hybrid photovoltaic-wind power generation systems. This methodology makes it possible to optimise the overall performance of the stand-alone system components, based on the premise of guaranteeing the power supply throughout the useful life of the installation at a minimum cost. The sizing is performed in two stages. Firstly, the components of the wind and photovoltaic power generation subsystem are obtained and, secondly, the size of the storage subsystem is determined. For the storage subsystem sizing, account is taken of the variation in efficiency according to the operating point and also the deterioration of the subsystem due to aging and, therefore, the loss of available energy during the useful life of the installation. This methodology is applied to a stand-alone traffic control system located on a secondary road in the Autonomous Community of Valencia (Spain). This system comprises wind and photovoltaic power generation components, a lithium battery bank and various traffic management components. Finally, an analysis of the proposed sizing is made. Satisfactory results are obtained, showing how the proposed methodology makes it possible to optimise the sizing of stand-alone systems with regard to the size of its components, cost and operation. [ABSTRACT FROM AUTHOR]

This paper aims to develop a sustainable energy chain that by means of a solar-driven electrolysis system produces renewable hydrogen used as fuel in fuel-cell-powered bicycles. The novel hydrogen bicycle model is the core of the bike-sharing program that is proposed in a Southern Italy tourist place. The sustainable energy chain development has required: i) the definition of the bike-sharing program based on some assumptions such as number of bicycles, number of routes, maximum number of trips per bike per day, mean driver weight, average cycling speed, etc.; ii) the analysis of the hydrogen bike performance; iii) the design of each involved energy sub-section such as the photovoltaic power plant, the hydrogen production system, the hydrogen storage unit and the hydrogen transportation and distribution section. The study has been conducted by implementing a design-sizing methodology. Results have highlighted that, according to the bike sharing program assumptions, the proposed sustainable energy chain consists of a 103 kWp PV power plant that, generating 129 MWh of electric energy, allows to produce 2190 kg of hydrogen by using an alkaline electrolyzer (16 kW). The bike sharing program, with 3772 km travelled in the selected area, contributes to reduce the greenhouse gas emission. [ABSTRACT FROM AUTHOR]

This research presents technical and cost-minimised design to decarbonise the heating network by using large-scale heat pump and thermal heat storage. In this paper, real hourly heat-consumption and heat-production cost data for the city of Aarhus, Denmark are used for calculating techno-economic feasibility of coupling the heating network with electrical grid. An optimum solution is suggested for the entire network with least amount of backup generation capacity, thermal heat storage capacity, natural gas boiler capacity and levelised cost of energy. Aarhus constitutes 5% of the Denmark's total heat demand and 4% of electrical load demand. This can be fulfilled with 160 MW of rated wind generation capacity, 35 MW of solar PV generation capacity, 45 MW of backup generation capacity, 221 MW of natural gas boiler capacity and 3.4 GWh of thermal heat storage capacity. The levelised cost of energy shows that, the coupling between the electrical grid and heating sector reduces the cost by more than 50% to 45  € /MWh. However, the cost-minimised design is possible with wind/solar mix of 85% and renewable energy penetration of 100%. Sensitivity analysis concedes that, the 100% decarbonisation of heating sector relies heavily upon the cost assumed for wind generation and solar PV generation, instead of the operation and maintenance cost for heat pump. Furthermore, the reduction in cost for wind generation and solar PV generation leads to the decrease in levelised cost of energy. Whereas, the reduction in cost for heat pump, thermal heat storage capacity and natural gas boiler capacity leads to an increase in renewable energy penetration. Sensitivity analysis further reveals that, increasing thermal heat storage capacity and the cost of selling excess renewable energy does not have major impact upon the levelised cost of energy and can be instrumental for the economic viability of fossil-free future. [ABSTRACT FROM AUTHOR]

Renewable energies are a key element of the modern sustainable development. They play a key role in contributing to the reduction of the impact of fossil sources and to the energy supply in remote areas where the electrical grid cannot be reached. Due to the intermittent nature of the primary renewable resource, the feasibility assessment, the performance evaluation and the lifecycle management of a renewable power plant are very complex activities. In order to achieve a more accurate system modelling, improve the productivity prediction and better plan the lifecycle management activities, the modelling of a renewable plant may consider not only the physical process of energy transformation, but also the stochastic variability of the primary resource and the degradation mechanisms that affect the aging of the plant components resulting, eventually, in the failure of the system. This paper presents a modelling approach which integrates both the deterministic and the stochastic nature of renewable power plants using a novel methodology inspired from reliability engineering: the Stochastic Hybrid Fault Tree Automaton. The main steps for the design of a renewable power plant are discussed and implemented to estimate the energy production of a real photovoltaic power plant by means of a Monte Carlo simulation process. The proposed approach, modelling the failure behavior of the system, helps also with the evaluation of other key performance indicators like the power plant and the service availability. [ABSTRACT FROM AUTHOR]

The marine economy has driven a quick development of offshore industrial infrastructure on the offshore islands in recent years. Due to the limitation of the geographical area and the shortage of power supply from the bulk electric power system, power supply from various forms of small-scale distributed generations (DGs) becomes a viable solution. However, these DGs are intermittent and stochastic in nature, which result in mismatch between generation and demand, increased fault level and degraded performance. This paper presents a fuzzy decision based approach and controller design method to address the energy dispatch in offshore industrial microgrid consisting of various forms of distributed generators (renewable sources and onsite diesel generators) and the seawater desalination system. The proposed fuzzy decision based dispatch solution is implemented fully considering the power generation and consumption relationship, the remaining amount of freshwater the state of charge of storage units, and without the requirement of accurate system models. The performance is validated through a case study and the numerical result demonstrates that the proposed fuzzy decision based solution can efficiently optimize the renewable energy utilization to meet the power supply-demand balance in offshore microgrid as well as maintain the fresh water supply stability. [ABSTRACT FROM AUTHOR]

The work presented in this paper deals with an assisted management of a standalone multi-source power system. The proposed structure consists of a wind turbine (WT) and a photovoltaic generator (PV) used as renewable sources, a super-capacitor (SC) as an energy storage system and a diesel generator (DG) as an emergency power supply. The aim of this work was to develop an assisted management strategy in order to control the power flow in the system operation with the highest reliability. Four limits of the SC state of charge (SOC) were defined states for the power control strategy. The main advantage of the used strategy was to protect the storage system from the deep charge and discharge and then increase its lifespan. The proposed energy management concept was tested in simulation by applying all possible cases. The obtained results confirm its efficiency and harmony between production and consumption was guaranteed. [ABSTRACT FROM AUTHOR]

The growing share of variable renewable energy (VRE) generation and the reduction in conventional power plant capacity creates challenges for power system operation. Increased variability of production causes increased reserve requirements while the number of reserve providers is reduced. For this reasons, power systems' flexibility is a major topic of research nowadays, and electricity demand is considered one of the most valuable flexibility sources. This paper analyzes the impacts of demand flexibility participation in spot and reserve markets in the German power system in 2030. We model the power system dispatch with and without reserve requirements using a partial equilibrium linear programming model, BalmoREG, to quantify the cost of reserves, the value of demand flexibility, and the optimal allocation between the spot market and reserve market. We find that the costs of providing reserves add 0.6–8.6% to the total system cost in the German 2030 power system. According to sensitivity studies, the cost of reserve provision increases substantially with reduced baseload shares or increased VRE shares, while transmission opportunities to neighboring countries reduce the cost. The modelled electricity price is especially sensitive to the addition of reserve requirements in situations of either very high VRE or very low VRE production. [ABSTRACT FROM AUTHOR]

This paper presents an economic and energy feasibility analysis of a renewable energy system for a small city in southern Italy to convert it to zero greenhouse gas city by 2030. The proposed energy infrastructure utilises different technologies: wind turbine, photovoltaic panels and biogas cogeneration plants to produce electric energy, and thermal solar panels, cogeneration and heat pumps to meet the thermal energy demand of the city. The electrification of transport sector is also considered. The whole city energy system is analysed by the EnergyPLAN software to evaluate streams combination and potential synergies between the different sectors. In order to improve the analysis, PhotoVoltaic technology has been simulated in TRNSYS environment, to obtain detailed prediction of this component of the energy infrastructure. The system behaviour was analysed considering different time bases: daily, weekly and yearly. The EnergyPLAN outputs include the aggregated yearly production and demands of all modelled energy conversion systems, as well as hourly values useful to identify the measures to make Altavilla Silentina nearly zero carbon city. Every measure identified becomes a new input in EnergyPLAN to evaluate its effect on city energy balance. The economic analysis has been performed to evaluate the electricity and thermal energy costs. [ABSTRACT FROM AUTHOR]

The massive deployment of plug-in electric vehicles (PEVs), renewable energy resources (RES), and distributed energy storage systems (DESS) has gained significant interest under the smart grid vision. However, their special features and operational characteristics have created a paradigm shift in distribution network resource allocation studies. This paper presents a combined model formulation for the concurrent optimal resource allocation of PEVs charging stations, RES and DESS in distribution networks. The formulation employs a general objective function that optimizes the total Annual Cost of Energy (ACOE). The decision variables in the formulation are the locations and capacities of PEVs charging stations, RES, and DESS units. A Markov Chain Monte Carlo (MCMC) simulation model is utilized to account for the uncertainties of PEVs charging demand and output generation of RES units. Also, in order to enhance the accuracy of the resource allocation problem, the coordinated control of PEVs charging, RES output power, and DESS charging/discharging are incorporated in the formulated model. The formulation is decomposed into two interdependent sub-problems and solved using a combination of metaheuristic and deterministic optimization techniques. A sample case study is presented to illustrate the performance of the algorithm. [ABSTRACT FROM AUTHOR]

synchronous generators are the most extensive generators used as electrical production component in a power plant. Many researches have been done to optimize their structure and their performances. This paper introduces a modern generation of synchronous machine. The introduced double-stator cup-rotor permanent-magnet synchronous generator (DSPMSG) was optimized, designed and simulated for high-power wind farms. Its structural features and operational principles were described and its specific equations have been extracted. Analytical hierarchy process (AHP) was used to optimize the designing parameters. The optimized parameters were used to simulate the generator on Maxwell based on Finite Element Method (FEM). The no-load and full load magnetic fields were computed by 2-D FEM and the simulation results were used to validate the whole designing processes. A comparison was made between the characteristics of the designed generator and a general permanent-magnet one. Finally, it was concluded that along with less electrical losses, less weight, length and diameter and simple structure, the most important feature of the proposed generator which is its more electrical energy production in a smaller size can resolve the limited performances of ordinary synchronous generators especially in high power wind applications besides other advantageous of doubled-stator ones. [ABSTRACT FROM AUTHOR]

Utilizing electric vehicles in transportation systems has emerged as a promising approach for reducing amount of fossil fuels. In order to provide a procedure to derive the optimal charging/discharging strategy of these vehicles, this paper proposes a bilevel approach in which distribution system operator and parking lot operator are its two main levels. In the upper-level, the objective is minimizing distribution system operator cost considering all available resources in the system including renewable generation and parking lot and in the lower-level the parking minimizes its own cost. In addition, the renewable generation uncertainty is covered through spinning reserve provided by both parking lot and distributed generations. The proposed method is able to strategically determine the amount of energy and reserve interacted between two operators through integrated operation of all the resources in the network. The bilevel problem is reduced to a single level optimization problem by using of a mathematical problem with equilibrium constraints. The results show that the use of parking lot in reserve scheduling changes the scheduling of other available resources in the system. Moreover, by implementing the proposed model, the global optimal performance for distribution system operator with various interactions can be achieved by the equilibrium point. [ABSTRACT FROM AUTHOR]

Near-future electric distribution grids operation will have to rely on demand-side flexibility, both by implementation of demand response strategies and by taking advantage of the intelligent management of increasingly common small-scale energy storage. The Home energy management system (HEMS), installed at low voltage residential clients, will play a crucial role on the flexibility provision to both system operators and market players like aggregators. Modeling and forecasting multi-period flexibility from residential prosumers, such as battery storage and electric water heater, while complying with internal constraints (comfort levels, data privacy) and uncertainty is a complex task. This papers describes a computational method that is capable of efficiently learn and define the feasibility flexibility space from controllable resources connected to a HEMS. An Evolutionary Particle Swarm Optimization (EPSO) algorithm is adopted and reshaped to derive a set of feasible temporal trajectories for the residential net-load, considering storage, flexible appliances, and predefined costumer preferences, as well as load and photovoltaic (PV) forecast uncertainty. A support vector data description (SVDD) algorithm is used to build models capable of classifying feasible and non-feasible HEMS operating trajectories upon request from an optimization/control algorithm operated by a DSO or market player. [ABSTRACT FROM AUTHOR]

Assessing the applicability of an energy storage system (ESS) based on its duty cycle, i.e., its charge/discharge profile, which represents the demands (associated with a specific application) on an ESS, has attracted great attention in the field of renewable energy. The duty cycle of an ESS is determined and analyzed in this paper. The process of obtaining the duty cycle includes extracting common factors from the ESS operation data using factor analysis, clustering the original fragments using a k -means clustering analysis of the common factors, and constructing typical duty-cycle curves using representative sections of each cluster dataset. The duty cycles of the ESS in schedule output, output smoothness, and schedule and smoothness combination applications, for example, were obtained and analyzed. In a schedule output application, the power ratio of the ESS is the primary characteristic parameter, and each band (high, mid, and low) of the power grade accounts for one third of the duty cycle. The changing rate of the power is the key to the assessment and evaluation of output smoothness. The duty cycle of the schedule and smoothness combination application can be treated as a linear superposition of independent duty cycles. The results showed that a combination of factor analysis and k -means clustering methods can effectively identify and quantify the characteristic parameters of the duty cycle to determine the applicability of the ESS. [ABSTRACT FROM AUTHOR]

The importance of renewable energy usage is increasing gradually due to the reasons of energy supplying security, environmental pollution and reducing dependency on external sources in all over the world as also same in Turkey. Biomass is a clean and sustainable energy source that can be produced from various kind of organic waste. Turkey has considerable biomass energy potential, and about 6% of the total potential is located in the eastern region. Ardahan is one of the eastern cities of the country whose economy mainly relies on livestock farming. This paper presents biogas energy potential from animal manure and agricultural residue and corresponding CO 2 emission reduction in Ardahan. Calculations were made according to the analysis of the animal manure and the agricultural crop quantities of 2015 data considering of the biochemical methane potential (BMP), availability factors, volatile solid ratio of the manure, harvested area and unit methane potential of cereals. The total electricity production potential of the evaluated biomass sources is 323 GWh/year. The total CO 2 emission reduction is about 2 million tons/year in the case of biogas combustion power plant exists instead of coal fired power plants. [ABSTRACT FROM AUTHOR]

Floating photovoltaic systems (FPV) can be a more sustainable alternative for the energy transition than ground-mounted photovoltaic systems, as they avoid occupying useable land and the power generation is more distributed. This paper presents the first study that calculates the FPV technical potential at the province/municipality level, focusing on water irrigation ponds, which it is a novelty in the literature that usually focuses on large water infrastructures in a national approach. In the province of Jaén (Spain), more than 3000 ponds dedicated to agricultural irrigation have been identified and their surface area and location was obtained. The results, calculated for each pond, reveal that, in a conservative scenario, in which only 25% of their surface area is covered, a minimum of 490 MWp can be installed, which can provide 251% of the province agricultural electricity consumption and 27% of the total electricity needs. This analysis has also been performed at the municipal level, where all possible FPV plants have been aggregated and compared with consumption that would be covered at this scale. Furthermore, this technology brings additional benefits, as it avoids the occupation of 12 km2 of useable land, 8.8·106 m3/year of water evaporated, while creating more than 7000 jobs. • A Technical floating PV potential assessment on water irrigation ponds is done • A Technical floating PV potential assessment at a municipal level is done • A calculation of Multi-benefits of floating PV installation is done • An energy consumption coverage assessment at municipal level with floating PV is done [ABSTRACT FROM AUTHOR]

This paper presents the simulation platform SWHORD, specially designed for the analysis of future energy systems under energy transition targets. The model is implemented in GAMS as a cost minimization mixed integer programming problem of a hydro-thermal power system, which includes high penetration of non-dispatchable renewable generation, storage technologies, electric vehicles, and hydrogen systems. Simulations are performed on an hourly basis for one year of operation, enabling the evaluation of both short-term dynamics and the seasonal behaviour of the system and including the hourly power generation profile by technology, fuel and emission costs, CO 2 emissions and storage levels, as well as the renewable curtailment needed to balance the system. The model was validated by backtesting with historical data of the Portuguese power system and, from a comprehensive statistical analysis of the dispatchable generation, it is concluded that the simulation results present a good fit with the real data. An illustrative use case is presented to evaluate the consistency of the Portuguese targets for 2030. Simulation results put in evidence the advantages of the SWHORD simulator to study the complex interactions among the new drivers of future energy systems, such as electric vehicles, storage technologies, and hydrogen systems. • Evolutive version of the power system simulator SWHORD for energy transition analysis. • Simulator computes yearly aggregated results and hourly profiles of power generation. • Example use case for the Portuguese power system considering hydrogen production. • 2030 hydrogen production is partially supplied with an increase in CCGT production. [ABSTRACT FROM AUTHOR]

This paper defines the diverging interests of multiple actors in typically achieving and advancing energy efficiency. Gaps in the literature include the short elaboration of energy efficiency factors and conditions and the lack of information about developed and developing countries and thorough consideration of their specific features, impeding the development and implementation of detailed energy efficiency management strategies. It is against this backdrop that this paper seeks to identify the essence of energy efficiency and developing specific recommendations for achieving the most beneficial effect and well-balanced energy efficiency on the global scale, within the achievements of international goals in sustainable development. The paper exposes the critical factors of energy efficiency, accurately models the best energy efficiency characteristics, and settles the best energy consumption structure. The methodological purpose is to find different energy efficiency scenarios and disentangle fundamental differences in energy efficiency in developed and developing countries. The paper indicates that the reasonable likelihood of noteworthy achievement results in energy efficiency with insignificant mid-term changes. We give recommendations about well-balanced energy efficiency on the global scale and global progress in sustainable development. • This paper disentangles key differences in energy efficiency in developed and developing countries. • We identify the essence of energy efficiency and develop recommendations for achieving balanced energy efficiency globally. • The paper models the best energy efficiency characteristics and settles the best energy consumption structure. • We give recommendations about well-balanced energy efficiency in sustainable development. • The study shows energy consumption optimization in terms of GDP structure, energy consumption, and sustainability. [ABSTRACT FROM AUTHOR]

Microgrids with renewable generation can improve environmental impact on remote islands. This paper presents a case study of a plan for a microgrid that addresses the inconsistency of renewable energy with governor control and the inertial force of a diesel generator. This paper aims to design of a microgrid without a battery storage system. The case study was modeled to determine the maximum amount of renewable generation that can be introduced while maintaining stable frequency and voltage within the transmission grid. Data from Japan's Teuri and Yagishiri islands were used. The findings of our study revealed that wind and photovoltaic power can account for about 20% of the generation in such a microgrid while maintaining frequency stability. Adjustment of the moment of inertia of diesel generators effectively compensates for the fluctuating output of renewable sources at small remote islands. The cost of such a microgrid could be recovered within 16–17 years. • Design method for a small-scale microgrid with renewable energy in remote islands. • The microgrid addresses the electricity with governor control and the inertial force. • Case study was modeled to determine the maximum amount of renewable generation. • Suitable setting of transformers can be installed to ensure a stable voltage supply. • Cost of the proposed microgrid would be recovered in about 16–17 years. [ABSTRACT FROM AUTHOR]

Microgrids with renewable generation can improve environmental impact on remote islands. This paper presents a case study of a plan for a microgrid that addresses the inconsistency of renewable energy with governor control and the inertial force of a diesel generator. This paper aims to design of a microgrid without a battery storage system. The case study was modeled to determine the maximum amount of renewable generation that can be introduced while maintaining stable frequency and voltage within the transmission grid. Data from Japan's Teuri and Yagishiri islands were used. The findings of our study revealed that wind and photovoltaic power can account for about 20% of the generation in such a microgrid while maintaining frequency stability. Adjustment of the moment of inertia of diesel generators effectively compensates for the fluctuating output of renewable sources at small remote islands. The cost of such a microgrid could be recovered within 16–17 years. • Design method for a small-scale microgrid with renewable energy in remote islands. • The microgrid addresses the electricity with governor control and the inertial force. • Case study was modeled to determine the maximum amount of renewable generation. • Suitable setting of transformers can be installed to ensure a stable voltage supply. • Cost of the proposed microgrid would be recovered in about 16–17 years. [ABSTRACT FROM AUTHOR]

In the future energy system, it is likely that there is more variation in the electricity prices due to higher share of renewable energy sources in electricity production. In this paper, the effects of more variable electricity prices were analyzed in a district heating (DH) system that includes both combined heat and power (CHP) plant, fired mainly by biomass and heat only boilers. The most cost optimal dimensioning and combination of heat storages, heat pumps and solar collectors are searched in three future electricity price scenarios. When the impacts of different system components were analyzed separately, it was found that especially a larger heat storage (1% of annual DH energy) is economical. In addition, the results indicate that the most economical size for a heat pump is around 20% of peak heat demand. Yet, the most profitable solution was to include both a heat storage and a heat pump in the DH system. According to our results, solar collector was not a profitable investment in the studied DH system. [ABSTRACT FROM AUTHOR]

The Danish government has set a target of being fossil fuel independent by 2050 implying that a high degree of inflexible renewable energy will be included in the energy system; biogas can add flexibility and potentially has a negative CO 2 -emission. In this paper, we investigate the socio-economic system costs of reaching a Danish biogas target of 3.8 PJ in the energy system, and how CO 2 -costs affect the system costs and biogas usage. We perform our analysis using the energy systems model, Balmorel, and expand the model with a common target for raw biogas and upgraded biogas (biomethane). Raw biogas can be used directly in heat and power production, while biomethane has the same properties as natural gas. Balmorel is altered such that natural gas and biomethane can be used in the same technologies. Several CO 2 -cost estimates are investigated; hereunder a high estimate for the expected CO 2 -externality costs. We find that system costs increase with CO 2 -costs in most cases, while the biogas target becomes socio-economically cheaper. In the case of a very high CO 2 -cost, system costs decrease and biomethane becomes the primary fuel. Furthermore, biomethane functions as regulating power and the Danish fuel consumption increases due to a higher electricity export. [ABSTRACT FROM AUTHOR]

The targets for renewable energy set by the European Union have resulted in a surge in consumption of wood pellets, and the demand is expected to further increase the next decade. We use economic modelling to assess the impact on global wood-based product markets of gradually increasing wood pellets consumption within the EU. Comparing a scenario wherein consumption is determined exclusively by market forces with one where EU consumption is set to double between 2015 and 2030, we characterize the deviation from the unregulated market equilibrium that would attain. Our results highlight the necessity of assessing market impacts over time, with a sufficient geographical disaggregation. An increased EU demand for wood pellets would, apart from increased EU production, results in increased imports. The main sources are projected to be Russia, Canada, and, particularly, the USA. The results indicate synergies and competition between wood-based products and wood pellets. In general sawmilling stand to gain from increased wood pellets' consumption, while the opposite holds for wood-based panels and most paper grades. Due to the feedstock mix used in production of wood pellets and wood-based products, effects vary over time and among different EU members, as well as between EU and other regions. [ABSTRACT FROM AUTHOR]

This paper presents an optimal planning and scheduling on energy storage systems (ESSs) for congestion management in electric power systems including renewable energy resources. The proposed problem finds optimal capacity and charging-discharging regime of ESSs. The storage units are optimally charged and discharged to tackle the uncertainty related to wind-solar units as well as relief congestion in the lines. Output power of solar and wind units is modeled by Gaussian probability distribution function (PDF) and Monte-Carlo simulation (MCS) is applied to tackle the uncertainty. Simulation results demonstrate that the proposed planning can manage congestion of the network efficiently while dealing with wind and solar resources uncertainties. [ABSTRACT FROM AUTHOR]

Several influential energy systems models indicate that renewable energy must provide a significant share of the world's electricity to limit global temperature rises to below 2 °C this century. To better represent the costs and other implications of this shift, it is important that these models realistically characterise the technical and economic potential of renewable energy technologies. Towards this goal, this paper presents the first temporally-explicit Geospatial Information System (GIS) methodology to characterise the global onshore wind energy potential with respect to topographical features, land use and environmental constraints. The approach combines the hourly NASA MERRA-2 global wind speed data set with the spatially-resolved DTU Global Wind Atlas. This yields high resolution global capacity factors for onshore wind, binned into seasonal and diurnal time-slices to capture the important temporal variability. For each country, the wind power generation capacity available for various capacity factor ranges is produced, and made freely available to the community. This data set can be used to assess the economically viable wind energy potential on a global or per-country basis, and as an input to various energy systems models. [ABSTRACT FROM AUTHOR]

The European Council has agreed ambitious EU climate and energy targets for 2030, including a 40% reduction in greenhouse gas emissions compared to 1990 levels and a minimum share of 27% renewable energy consumption. This paper investigates the challenges faced by the European power systems as the EU transitions towards a low carbon energy system with increased amounts of variable renewable electricity generation. The research here adds value to, and complements the power systems results of the PRIMES energy systems model that is used to inform EU energy and climate policy. The methodology uses a soft-linking approach that scrutinizes the power system in high temporal and technical detail for a target year. This enables generation of additional results that provide new insights not possible using a single model approach. These results point to: 1) overestimation of variable renewable generation by 2.4% 2) curtailment in excess of 11% in isolated member states 3) EU interconnector congestion average of 24% 4) reduced wholesale electricity pricing and few run hours raising concerns for the financial remuneration of conventional generation 5) maintenance of sufficient levels of system inertia in member states becomes challenging with significant penetrations of variable renewable generation. [ABSTRACT FROM AUTHOR]

A reference scheme of a multiple energy complementation system is of great importance of Chongming's energy system development. In this paper, four feasible scenarios which are distinguished by energy supply forms have been discussed based on RETScreen software. Economic analysis as well as the renewable sources penetration was taken into account. The outcome of equipment size optimization of each subsystem was summarized and the comparison between different scenarios was afterwards conducted in order to provide some thoughtful comments for the future energy system construction. Results indicate that the introduction of natural gas based CHP system and biomass system is a necessity for covering the energy demand and minimizing the energy import. The CHP scenario achieves the most annual balance (0.3272 billion yuan) and net present value (2.556 billion yuan) and cuts down the GHG emission by 1.978 Mt per year. Moreover, the net present value of the proposed energy system is sensitive to the variation in energy policy. When the financial aids fluctuates by 50%, the net present value can change in the range from 60% to 70%. However, even when the policy is extremely unfavorable, the economical profit of CHP scenario is still obvious. [ABSTRACT FROM AUTHOR]

This paper examines the relationship between renewable energy production and greenhouse gas emissions (GHG) using U.S. state-level data for 2010. After controlling for other sources of emissions, U.S. states that produce a larger share of renewable energy are found to have lower GHG emissions. It is estimated that a 10% increase in the share of renewable energy could decrease CH 4 emissions by about 0.26%. Since the use of renewable energy sources does not release GHG emissions, this effect can be interpreted as stabilizing if renewable energy is added to coal use or as corrective if it replaces coal. After accounting for the role of coal as a baseload power source, an increase in the share of renewable energy is estimated to mitigate N 2 O emissions at the U.S. state level only if states individually decrease their share of coal use to levels below 41.47%. These findings have significant policy implications for the provision of guidance to policymakers in identifying optimal energy mixes and in pursuing realistic goals to enhance renewable energy penetration and to contribute to the current efforts of tackling climate change. [ABSTRACT FROM AUTHOR]

With the development of home area network, residents have the opportunity to schedule their power usage at the home by themselves aiming at reducing electricity expenses. Moreover, as renewable energy sources are deployed in home, an energy management system needs to consider both energy consumption and generation simultaneously to minimize the energy cost. In this paper, a smart home energy management model has been presented that considers both energy consumption and generation simultaneously. The proposed model arranges the household electrical and thermal appliances for operation such that the monetary expense of a customer is minimized based on the time-varying pricing model. In this model, the home gateway receives the electricity price information as well as the resident desired options in order to efficiently schedule the appliances and shave the peak as well. The scheduling approach is tested on a typical home including variety of home appliances, a small wind turbine, PV panel and a battery over a 24-h period. [ABSTRACT FROM AUTHOR]

Photovoltaic (PV) cell plays crucial role to utilize the solar energy. The regional differences in the PV industry have created unbalanced flows of PV cells. This paper examined patterns of the PV cells international trade from spatial and temporal perspectives. Data sources are regional monetary import-export tables and the world renewable energy statistics in 1996–2015. Based on the Haggett's cognitive model of spatial structure, the patterns and evolution characteristics are identified with an aid of ArcGIS. This study revealed most PV cells exporters are distributed in East Asia and Southeast Asia intensively whereas relatively balanced exports are presented in Europe and North American in recent years. Most PV cells are flowing from east to west while the pattern of PV cells international trade has transformed from single-pole to multi-pole. Meanwhile, the international trade intensity of PV cells grew steadily at the global scale, and evolution features of PV cells trades varied from region to region. Economics conditions, incentive policy and producers' demand are three critical factors. These findings provide a useful reference for identifying the intensity, orientation, main connections and development trend of traders. Moreover, the PV industrial practitioners can benefit from this research to develop corresponding international business strategies. [ABSTRACT FROM AUTHOR]

A microgrid optimal scheduling model is developed in this paper to demonstrate microgrid's capability in offering ancillary services to the utility grid. The application of localized ancillary services is of significant importance to grid operators as the growing proliferation of distributed renewable energy resources, mainly solar generation, is causing major technical challenges in supply-load balance. The proposed microgrid optimal scheduling model coordinates the microgrid net load with the aggregated consumers/prosumers net load in its connected distribution feeder to capture both inter-hour and intra-hour net load variations. In particular, net load variations for three various time resolutions are considered, including hourly ramping, 10-min based load following, and 1-min based frequency regulation. Numerical simulations on a test distribution feeder with one microgrid and several consumers/prosumers indicate the effectiveness of the proposed model and the viability of the microgrid application in supporting grid operation. [ABSTRACT FROM AUTHOR]

Distributed energy resources DERs are small scale energy system which could provide local supply when placed at customers' premises. They aggregate multiple local and diffuse production installations, consumer facilities, storage facilities and monitoring tools and demand management. The main challenges when assessing the performance of an off-grid hybrid micro-grid system HMGS are the reliability of the system, the cost of electricity production and the operation environmental impact. Hence the tradeoff between three conflicting objectives makes the design of an optimal HMGS seen as a multi-objective optimization task. In this paper, we consider the optimization and the assessment of a HMGS in different Swedish cities to point out the potential of each location for HMGS investment. The HMGS consists of photovoltaic panels, wind turbines, diesel generator and battery storage. The HMGS model was simulated under one-year weather conditions data. A multi objective particle swarm optimization is used to find the optimal system configuration and the optimal component size for each location. An energy management system is applied to manage the operation of the different component of the system when feeding the load. The techno economics analysis shows the potential of HMGS in the Swedish rural development. [ABSTRACT FROM AUTHOR]

Beijing, as the capital of China, is under the high pressure of climate change and pollution. The consumption of non-renewable energy is one of the most important sources of the CO 2 emissions, which cause climate changes. This paper presents a study on the energy system modelling towards renewable energy and low carbon development for the city of Beijing. The analysis of energy system modelling is organized in two steps to explore the alternative renewable energy system in Beijing. Firstly, a reference energy system of Beijing is created based on the available data in 2014. The EnergyPLAN , an energy system analysis tool, is chosen to develop the reference energy model. Secondly, this reference model is used to investigate the alternative energy system for integrating renewable energies. Three scenarios are developed towards the energy system of Beijing in 2030, which are: (i) reference scenario 2030 , (ii) BAU ( business as usual ) scenario 2030 , and (iii) RES ( renewable energies ) scenario 2030 . The 100% renewable energy system with zero CO 2 emissions can be achieved by increasing solar energy, biomass and municipal solid waste (MSW) and optimizing heating system. The primary fuel consumption is reduced to 155.9 TWh in the RES scenario, which is 72% of fuel consumption in the reference scenario 2030. [ABSTRACT FROM AUTHOR]

Renewable energy plays significant role in achieving energy savings and emissions reduction. As a sustainable and environmental friendly renewable energy source, concentrated solar power (CSP) is of interest for research and development. This is because CSP plants can be equipped with thermal storage systems, thereby producing electricity when sunlight is not available. The installation of CSP plants also leads to substantial ‘peak shaving effects’. However, the cost of CSP generation is an obstacle hampering the commercialization of this emerging industry. This paper constructs a mathematical model of the levelized cost of energy (LCOE) to calculate the power generation cost of CSP projects on the basis of lifetime cost structure analysis. A sensitivity analysis is conducted to examine the impact of different variables on the LCOE of CSP projects. The variables considered in this study are investment cost over the construction period, annual operation and maintenance cost, annual electricity production and the discount rate. Finally, the influence of incentive policies such as preferential loans, tax support and zero land cost for power stations is analyzed. This research offers a new method for power generation cost calculation of CSP projects and provides support for governments to formulate incentive policies for the industry. [ABSTRACT FROM AUTHOR]

Currently, significant energy consumption is one of the main technical barriers to the large-scale application of CO 2 capture technology. A novel concept—carbon pump—is proposed in this paper to analyze the energy-efficiency of these technologies. The analysis model, which embodies the carbon pump concept, includes the minimum CO 2 separation work and the second-law efficiency. Based on this model, the proposed method is applied to comparative analysis of current capture technologies considering both the quantity of energy consumption and the grade of difficulty level for CO 2 separation. The analyzed results show that the second-law efficiencies of the statistical cases are below 35%. For post-combustion technologies with CO 2 concentrations ranging from 5% to 15%, the higher group of second-law efficiency is approximately above 15%, and the lower is approximately 10% or lower. It can be concluded that a great energy-saving potential still exists in post-combustion technologies through improving the efficiency of heat exchanger and pump, developing new materials, and network optimization. Additionally, integrating renewable energy into capture technologies is an important measure for reducing the consumption of primary energy and the carbon footprint of the whole system. [ABSTRACT FROM AUTHOR]

Renewable energy has the characteristics of wide distribution, sustainable use and low impact on the environment, which is suitable for application and promotion in the island area. Given the concerns about wind and PV curtailment of energy-rich islands, it is potentially a good idea to export extra renewable energy to the mainland. The aim of this paper is to investigate the economic viability of transforming renewable energy into exportable electricity or hydrogen. A comprehensive renewable energy system model is developed based on the P-graph to simulate an energy system, which integrates electricity, heat and hydrogen on a virtual island. Solar, wind, wave and biomass are the main renewable energy sources in the developed energy system. The objective includes the construction cost, operating cost, and also environmental cost, which is related to the greenhouse gas footprint. Findings from the case study show that extra renewable energy exporting by electricity is cheaper than using hydrogen for the studied island, and the optimal dispatch structure can deliver 51 GWh of electricity annually for 292 M CNY (about 42 M EUR). A sensitivity analysis of export prices and renewable energy uncertainty verifies the economics of electricity export. [Display omitted] • Evaluating the economic benefit of exporting excess renewable energy from islands. • Both the electricity and heating demands of the island are taken into account. • The hydrogen can be exported and used for cogeneration in fuel cells. • Exporting electricity is more economical in the case of island. [ABSTRACT FROM AUTHOR]

This paper investigates the effect of renewable energy consumption on material consumption, considering the relationship between Material Footrprint and Gross Domestic Product (GDP), and testing the assumptions of the Environmental Kuznets Curve. A STIRPAT variation is used to specify a model relating the Material Footprint to renewable energy consumption and GDP. The effect is tested for the Material Footprint of fossil fuels and for the Material Footprint of the other categories. The analysis is applied to the seven European countries with the highest proportion of renewable energy consumption. The model estimation shows that the relationship between GDP and Material Footprint follows an inverted N-shaped form, and that the renewable energy favours the reduction of the material consumption of fossil fuels. However, there is a positive effect between the renewable energy consumption and the Material Footprint of the other categories beyond fossil fuels. These results must be interpreted considering the context, as the development of renewable energy coincides with the effects of the 2008 crisis, which may distort the relation between the variables. To pose dematerialization scenarios, it seems necessary to consider reducing energy consumption even if it comes from renewable sources. • The hypotheses of the Environmental Kuzntes Curve are tested. • Renewable energy does not seem to contribute to dematerialization. • Renewable energy contributes to reducing the consumption of Fossil Fuels. • An inverted N-shaped relationship between the Material Footprint and GDP is verified. [ABSTRACT FROM AUTHOR]