European Union has definitely identified the priorities towards sustainable and low-carbon energy systems recognizing a key role to islands that have been described as ideal sites to develop and test ...innovative strategies and solutions that will then boost the transition on the mainland. Nevertheless, the integration of Variable Renewable Energy Sources (vRES) into the electricity grid are already causing technical problems to island grids thus making grid flexibility a key topic. In the past, since power plants were completely manageable while the load was unpredictable, the grid flexibility was supplied by traditional power plants; but now, due to vRES, the variability and unpredictability has moved to the generation side and the opposite shift has happened to flexibility agents. This paper deals with solutions that improve the ability of the grid to cope with vRES unpredictability such as energy storage technologies and all the solutions offered by sector coupling strategies. Particularly, this research focus on solutions that deals with such solutions in the insular contexts. Several solutions have been presented concluding that battery energy systems and pumped hydro energy storage are the most used technologies in islands. As regard sector coupling and Demand Side Management solutions, all the analysed solutions showed relevant results in terms of i) reduction of excess electricity production and ii) increased grid ability of hosting vRES. Nevertheless, some of the current gaps in literature have been pinpointed and future research challenge and opportunities have been suggested.
•Review on the effects of energy storage technologies on insular grid flexibility.•Review on demand side management solutions to handle vRES in insular energy systems.•Review of flexibility and sector coupling solutions for smart energy islands.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Bioenergy can be produced from a wide range of feedstocks and can be utilised for production of renewable electricity, thermal energy, chemicals or transportation fuels. Anaerobic digestion ...technology (AD) for biogas production has an important role in achieving circular economy goals, as it may not only recover the energy contained in the biomass but also contribute to nutrient recovery and reduction of greenhouse gas emissions. The expansion of biogas production promotes the need for assessment of the technical potential of biomass, which is available for biogas production and is not in the competition with other purposes. This research work presents a Geographical Information System (GIS) based approach for the assessment of the spatial distribution of the biogas production potential by taking into consideration seasonal variation of biomass production, in order to assess the influence of biomass seasonality. The method developed in this research work is based on a combination of statistical and spatial explicit methods. The presented approach was tested in a case study of Croatia and the final results are representing the seasonal and spatial distribution of biogas potential at the spatial level of 1 km × 1 km. The results show that there is a strong need to include the influence of seasonality in assessment of biogas potential for lignocellulosic agricultural residues. The benefits are demonstrated in two examples that resulted in 12% and 40% lower storage facility capacity by using the proposed approach, compared to currently used approaches.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This paper is the editorial for the virtual special issue (VSI) of Renewable and Sustainable Energy Reviews (RSER) dedicated to 4 SDEWES Conferences held in 2020, namely: (i) the 2nd Latin American ...Conference on Sustainable Development of Energy, Water and Environment Systems (LASDEWES 2020) held from February 9 to 12, 2020 in Buenos Aires, Argentina; (ii) the 1st Asia Pacific Conference on Sustainable Development of Energy, Water and Environment Systems (APSDEWES 2020) held from April 6 to 9, 2020 in Gold Coast, Australia; (iii) the 4th South East European Conference on Sustainable Development of Energy, Water and Environment Systems (SEESDEWES 2020) held from June 28, 2020 to July 2, 2020 in Sarajevo, Bosnia Herzegovina, and (iv) 15th Conference on Sustainable Development of Energy, Water and Environment Systems (SDEWES 2020) held from September 1 to 5, 2020 in Cologne, Germany. The VSI collected both high quality review papers and original research articles presented at the 4 SDEWES conferences in 2020 belonging to the aims and scope of RSER. After a scrutinizing peer review process, 20 articles were accepted and published. These articles fall into four main areas: renewable energy cutting edge technologies, energy storage, energy modelling techniques and, climate and energy policy and impacts. Cross-areas articles belong to this Special Issue covering almost all the Sustainable Development Goals (SDGs).
•The VSI SDEWES 2020 covers four main areas.•An overview of the renewable and sustainable energy challenges to be dealt.•Cross-areas studies help addressing SDGs.•The advances and the novel findings for the successful achievements of ambitious policy targets.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•A PV-load decoupling framework is proposed to improve the baseline load estimation.•A machine learning approach is proposed to estimate PV capacity from net load data.•An optimal pairing and SVR ...based approach is proposed to improve the estimation.
Accurate customer baseline load (CBL) estimation is critical for implementing incentive-based demand response (DR) programs. The increasing penetration of grid-tied distributed photovoltaic systems (DPVS) complicates customers’ load patterns, making the CBL estimation more difficult because the volatile actual load and the intermittent PV output power are coupled together. A PV-load decoupling framework is proposed in this paper to address the above issue. The basic idea is to decouple the actual load power and the PV output power, then estimate them separately. To this end, historical PV output power data of each individual DPVS is required. However, pure historical PV output power data is usually unavailable for small-scale DPVSs, since they are normally located behind the meter, thus only the net load (i.e. actual load power minus PV output power) data is metered. Therefore, this paper proposes a machine learning approach to disaggregate the output power of each individual DPVS from net load data. The proposed approach includes two stages: DPVS capacity estimation and PV output power estimation. The first stage consists of two steps. First, a net load curve optimal pairing-based feature extraction method is proposed to extract features from the discrepancy between two different net load curves of the customers under heterogeneous weather conditions. Second, a multiple support vector regression-based ensemble model with the input features extracted in the first step is established to estimate the DPVS capacity. In the second stage, the output power of each DPVS is estimated by its capacity multiplied by the output power of a standard DPVS. Case studies using a real dataset from Sydney indicate that the proposed approach shows a promising performance on PV output power estimation and can significantly improve the CBL estimation accuracy for customers with DPVSs.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The goal of this work is to identify the influence which utilization of district heating systems coupled with the power-to-heat technologies based on the flexible operation of coal-based thermal ...power plants and limited electricity system interconnections can have on the maximum integration of variable renewables. An hourly deterministic tool EnergyPLAN was used for modelling and simulation of Kosovo energy system. Results revealed that Wind and PV power plant capacities of 450 MW and 300 MW respectively can be installed in the actual Kosovo energy system, when operating in an isolated mode. Additional capacities around 800 MW for wind and 385 MW for PV can be integrated into this isolated energy system with the contribution of power-to-heat technologies coupled with thermal energy storage in district heating with a fixed capacity. Furthermore, it was found that separate integration of wind can contribute to decease total primary energy supply and CO2 emissions for 3.34 TWh/year and 1.08 Mt compared to the referent scenario. Total primary energy supply and CO2 emission savings for separate integration of PV power plant compared with the referent scenario were estimated 2.74 TWh/year and 0.5 Mt respectively. Finally, the combined integration of variable renewable energy sources (1MWW+1MWPV) contributed to 3.29 TWh/year total primary energy supply and 1.02 Mt CO2 emissions savings.
•A method for increasing variable renewables in coal based energy systems was developed and investigated.•Power to heat felicity contribution to increase renewables was emphasized.•Investment costs for integrated variable renewable technologies.•Research show the total primary energy and CO2 emission savings.•The approach is applied for Kosovo case, but the methodology can be applied elsewhere.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The European Union and other signatories to the Paris Climate Accord have agreed to limit global warming to 2° Celsius above pre-industrial levels. Previously published studies have examined the ...optimal energy system structure required to satisfy carbon neutrality end goals. This research focuses on addressing the intermediate steps towards decarbonization. The steps are quantified as the percentage share of renewable energy sources. The objective of the optimization is to reach a predetermined level of renewable energy and emissions, minimize curtailment of renewable energy sources, minimize system cost, and limit the use of natural resources such as biomass in the energy sector. Considered technologies in the optimization process are energy-generating capacities, demand response technologies, and energy storage. The results of such a method reflect the use of considered technologies and are displayed as a function of renewable energy share and carbon dioxide emissions level, which also represent the decarbonization timeline from 2020 to 2050. The method is carried out with the use of energy planning software EnergyPLAN and highly modified Python-based optimization software EPLANopt. The results presented in the research display the necessity for continuous implementation of variable generating capacities as well as demand response technologies, mainly vehicle to grid.
•Optimization of the energy system in multiple steps towards a fully renewable system.•Consideration of excess generation, total cost, emissions and the use of biomass.•Use of EnergyPLAN in combination with EPLANopt.•Expansion of EPLANopt functionalities.•The model is now capable of modelling more complex relations.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This paper addresses the optimal decision problem of a distributed energy resources (DER) aggregator who manages wind turbines, solar PV systems and battery energy storage (BES) units while ...implementing real-time pricing (RTP) demand response program. The DER aggregator can procure electricity by bidding in the electricity market and scheduling its DER to meet the load demand of its customers. In the bidding and scheduling processes, the intrinsic uncertainties of distributed renewable generations and customer’s responsiveness to RTP program have brought economical risks to the DER aggregator, which will lower the DER aggregator’s profit. However, most of the current researches only consider the uncertainty of renewable generations while neglecting the uncertainty of customer’s responsiveness. To this end, a robust optimization-based day-ahead optimal bidding and scheduling model is proposed for DER aggregator by jointly considering these two uncertainties. The objective of the proposed model is to maximize the aggregator’s profit via optimally determining the hourly bidding quantities in the day-ahead market and the scheduled output power of distributed renewable generations and BES units. Case studies demonstrate that the proposed robust optimization model can help DER aggregator reduce the bidding and scheduling costs to obtain a higher expected profit.
•The impact mechanism of price responsive load uncertainty is revealed.•Optimal bidding and scheduling strategies of a DER aggregator are proposed.•The necessity of considering price responsive load uncertainty is verified.•The proposed method is more effective for more price-sensitive customers.
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This paper provides a systematic review of 34 large-scale projects of power-to-heat demand response. The projects have been classified in terms of location, size, technical implementation and ...objective. The chronological ordering of the reviewed projects enables key takeaways to be drawn considering other developments in the energy sector, such as its restructuring and the emergence of competing flexibility options. The presented approach provides renewed insight to the debate on power-to-heat demand response diffusion. Historically, power-to-heat demand response has been used because of its wide availability on the demand side. Within utility programs, it has mostly been used to deal with infrastructure capacity limitations. This is still a major driver for power-to-heat demand response today. To address the challenges that come with the integration of renewable energy sources, more recent research projects have focused on exploring its capability to provide real-time balancing and frequency response at a smaller scale. The literature review suggests that the period of energy sector restructuring introduced uncertainty to energy companies regarding power-to-heat demand response and thus influenced its use. This period is now superseded by developments focused on electricity markets that are open to the demand side. Considering the flexibility requirement of the future energy system, new opportunities arise for power-to-heat demand response. Based on a critical analysis of the technical and regulatory changes, this paper makes the claim that the economic and policy frameworks have had a much more significant effect on the varying diffusion of power-to-heat demand response than the effect of the control and information technologies. In that sense, market rules should be carefully tailored so as to unlock the flexibility not only of power-to-heat demand response, but also of other flexibility resources.
•P2H DR has multiple capabilities suitable for different time scales.•Technical feasibility of P2H DR is not a significant barrier.•Framework uncertainty has a significant effect on P2H DR diffusion.•Markets and flexibility requirement introduce new option for P2H DR.
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Since the signing of the Paris Climate Agreement, European Union has made contributions to increase the share of renewable energy in its energy mix and limit global warming to 2 °C. Additionally, the ...European Union has with the passing of the “European Green Deal”, set a plan to transition to a carbon-neutral economy by 2050 which is planned to be achieved by the implementation of renewable energy generating capacities and parallel implementation of sector coupling, energy balancing, and storage technologies. These technologies are required to avoid the emergence of new problems like curtailment and jeopardization of system stability. The application of these technologies may vary due to their operating characteristics as well as the costs associated with them. The goal of this research is to show the most economically viable dynamics of achieving high penetration of renewable energy in combination with different flexibility options on a case study. Application of flexibility options is considered with the goal of keeping critical excess electricity generation within 5% of total electricity demand. The simulations are performed with the combination of energy planning software EnergyPLAN and an optimization software EPLANopt.
Results show that the most effective technologies are the vehicle to grid, smart charge, improvements of energy efficiency, and pumped hydro storage.
•Optimization of Croatian energy system towards fully renewable system.•Consideration of CEEP, total cost, CO2 emissions and the use of Biomass.•Use of EnergyPLAN in combination with EPLANopt.•Performance of flexibility and balancing technologies at various shares of RES.•New method of comparing the technology utilization.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Sustainable island energy systems have been a subject of academic research for some time. Real-life examples of highly renewable and sustainable island energy systems can be found all over the World. ...Islands on small geographic proximity provide the potential for the development of 100% renewable island energy systems by exploiting their grid interconnections. This paper proposes that interconnections of a group of islands can be used to integrate the production from locally available renewable energy sources. Besides interconnection, electric vehicles were used as a demand response technology to provide storage for electrical energy from variable sources. Electric vehicles were connected to the grid using smart charging systems (vehicle-to-grid). In addition, stationary batteries were explored in sub-scenarios for the year 2035. This enabled to analyse the influence of the battery location through two main different scenarios, i.e. one big central battery and several smaller distributed batteries. Scenarios with different integration dynamic of variable renewable energy sources and electrical vehicles were modelled with EnergyPLAN model, while the interconnection analysis was carried out with the MultiNode tool expansion. The results showed that the interconnections increased the share of energy from renewable energy sources in the final energy consumption and declined the total critical excess electricity production, while vehicle to grid technology enabled exploitation of synergies between sectors.
•The energy system of grid connected islands is built with EnergyPLAN model.•Island models connected in the archipelago by using MultiNode tool.•Impact of RES integration with DR technologies and stationary batteries is observed.•No fossil fuel powered generators were used.•Influence of distribution of stationary batteries on energy flows is studied.
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