| 1. |
- Abdelshafy, Alaaeldin M., et al.
(författare)
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Optimized energy management strategy for grid connected double storage (pumped storage-battery) system powered by renewable energy resources
- 2020
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Ingår i: Energy. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0360-5442 .- 1873-6785. ; 192
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a grid-connected double storage system (DSS) consisting of pumped-storage hydropower (PSH) and battery. The system is supplied by photovoltaics and wind turbines. In the proposed hybrid system, batteries absorb excess renewable energy that cannot be stored in PSH and they cover loads that cannot be supplied from the water turbine. To improve the system performance, a novel energy management strategy for the DSS is proposed. The strategy is based on an optimized factor that governs the charging process of the DSS. The problem of the optimal system design is solved by a non-dominated sorting genetic algorithm (NSGA-II). The multi-objective function considers simultaneously the minimal investment cost and minimal CO2 emissions. A comparative study of photovoltaic/wind/pumped-storage hydropower and photovoltaic/wind/double storage system is performed to show the effectiveness of the proposed strategy in terms of system economic and environmental performance. The considered location of the PSH station is on Attaqa Mountain at Suez (Egypt). The results indicate the effectiveness of the proposed energy management strategy for the storage system from economic and environmental perspectives. Coupling the battery with the PSH reduces the electricity cost by 22.2% and results in minimal energy exchange with the national grid (5% of the annual demand). A sensitivity analysis shows the largest variation of the electricity cost with changing the capital cost of the solar and wind generators. Also, it is observed that when the load increases, the optimal size of the system components increases, but it isn't proportional with the demand increase as could be expected. (C) 2019 Elsevier Ltd. All rights reserved.
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| 2. |
- Belhomme, Regine, et al.
(författare)
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Bottom-Up Flexibility in Multi-Energy Systems : Real-World Experiences From Europe
- 2021
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Ingår i: IEEE Power and Energy Magazine. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 1540-7977 .- 1558-4216. ; 19:4, s. 74-85
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Tidskriftsartikel (refereegranskat)abstract
- Electricity Systems in europe are experiencing major changes due to targets for renewable energy integration, reducing greenhouse gas emissions, and energy efficiency. Different studies show that there is a growing need for more flexibility and active stakeholder involvement at all levels (from small consumers to pan-European networks) to ensure the efficient and reliable operation of the electricity system, particularly to deal with growing volumes of renewable energy sources, from transmission-level wind and solar farms to household-level photovoltaic generation. Other key evolutions that aim to decarbonize the energy sector beyond electricity, such as those based on the electrification of energy end uses (e.g., the development of electric vehicles and the electrification of heating), are also expected to have a substantial impact.
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| 3. |
- Campana, Pietro Elia, 1984-, et al.
(författare)
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Li-ion batteries for peak shaving, price arbitrage, and photovoltaic self-consumption in commercial buildings : A Monte Carlo Analysis
- 2021
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Ingår i: Energy Conversion and Management. - : Elsevier BV. - 0196-8904 .- 1879-2227. ; 234
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Tidskriftsartikel (refereegranskat)abstract
- This study investigates the benefits of introducing Li-ion batteries as energy storage unit in the commercial sector by considering a representative building with a photovoltaic system. Only the costs and revenues related to the installation and operation of the battery are considered in this study. The operational strategy of the battery consists in balancing the following processes through day-ahead forecasts for both electricity consumption and photovoltaic production: shaving a targeted peak, performing price arbitrage, and increasing photovoltaic selfconsumption. By reviewing the electricity price cost for commercial buildings from several companies around the world, a general electricity price structure is defined. Afterwards, a Monte Carlo Analysis is applied for three locations with different solar irradiation levels to study the impact of climate, electricity price components, and other seven sensitive parameters on the economic viability of Li-ion batteries. The Monte Carlo Analysis shows that the most sensitive parameters for the net present value are the battery capacity, the battery price, and the component of the electricity price that relates to the peak power consumption. For Stockholm, one of the investigated locations, the corresponding Pearson correlation coefficients are -0.67, -0.66, and 0.19 for the case were no photovoltaic system is installed. For the considered battery operational strategies, the current investment and annual operation costs for the Li-ion battery always lead to negative net present values independently of the location. Battery prices lower than 250 US$/kWh start to manifest positive net present values when combining peak shaving, price arbitrage, and photovoltaic self-consumption. However, the integration of a photovoltaic system leads to a reduced economic viability of the battery by reducing the revenues generated by the battery while performing peak shaving.
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| 4. |
- Canales, Fausto A., et al.
(författare)
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Assessing temporal complementarity between three variable energy sources through correlation and compromise programming
- 2020
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Ingår i: Energy. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0360-5442 .- 1873-6785. ; 192
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Tidskriftsartikel (refereegranskat)abstract
- Renewable energies are deployed worldwide to mitigate climate change and push power systems towards sustainability. Nevertheless, the weather-dependent nature and variability of renewable energy sources often hinders their integration to national grids. The combination of different sources to profit from their beneficial complementarity has often been proposed as a partial solution to overcome these issues. This paper introduces a novel method for quantifying total temporal energetic complementarity between three different variable renewable sources, based on well-known mathematical techniques: correlation coefficients and compromise programming. It has the major advantage of allowing the simultaneous assessment of partial and total complementarity, as well as allowing for a linear assessment of complementarity. The method is employed to study the complementarity of wind, solar and hydropower generation on different temporal scales in a region of Poland. Results show that timescale selection has a determinant impact on the estimated value of the total temporal complementarity index. (C) 2019 Elsevier Ltd. All rights reserved.
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| 5. |
- Canales, Fausto A., et al.
(författare)
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Cost-reliability analysis of hybrid pumped-battery storage for solar and wind energy integration in an island community
- 2021
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Ingår i: Sustainable Energy Technologies and Assessments. - : ELSEVIER. - 2213-1388 .- 2213-1396. ; 44
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a mathematical model for estimating the optimal sizing and assessing a standalone hybrid power system's performance entirely based on variable renewable energy sources and coupled with a hybrid energy storage system. This study evaluates how different levels of the main components' capital cost and the loss of power supply probability would affect the cost of energy and the power system's optimal sizing. The case study selected for this study was Ometepe Island in Nicaragua, where the crater lake of an extinct volcano was considered a feasible upper reservoir of a pumped storage hydropower plant, reducing the investments associated with this component. The mathematical formulation considers energy storage losses and gains, and the Pareto efficient solutions of the multi-objective optimization model simultaneously increase reliability, reduce the cost of energy, and minimize curtailment energy. By employing time-series with an hourly resolution, the model allows assessing the impact of the interannual variability of renewable energy sources on the system's performance. As for the case study, the cost of energy obtained from the model results ranges between (sic)0.047/kWh and (sic)0.095/kWh, based on international reference values, and these values match the information available in the literature and other databases.
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| 6. |
- Canales, Fausto A., et al.
(författare)
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Spatial representation of temporal complementarity between three variable energy sources using correlation coefficients and compromise programming
- 2020
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Ingår i: MethodsX. - : Elsevier BV. - 2215-0161. ; 7, s. 100871-100871
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Tidskriftsartikel (refereegranskat)abstract
- Renewable energy sources have shown remarkable growth in recent times in terms of their contribution to sustainable societies. However, integrating them into the national power grids is usually hindered because of their weather-dependent nature and variability. The combination of different sources to profit from their beneficial complementarity has often been proposed as a partial solution to overcome these issues. Thus, efficient planning for optimizing the exploitation of these energy resources requires different types of decision support tools. A mathematical index for assessing energetic complementarity between multiple energy sources constitutes an important tool for this purpose, allowing a comparison of complementarity between existing facilities at different planning stages and also allowing a dynamic assessment of complementarity between variable energy sources throughout the operation, assisting in the dispatch of power supplies. This article presents a method for quantifying and spatially representing the total temporal energetic complementarity between three different variable renewable sources, through an index created from correlation coefficients and compromise programming. The method is employed to study the complementarity of wind speed, solar radiation and surface runoff on a monthly scale using continental Colombia as a case study during the year of 2015.•This paper describes a method for quantifying and spatially representing energetic complementarity between three renewable energy sources.•The method quantifies energetic complementarity by combining known metrics: correlations and compromise programming.•The proposed index for energetic complementarity assessment is sensitive to the time scale adopted.
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| 7. |
- Ciapala, Bartlomiej, et al.
(författare)
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Climate factors influencing effective use of geothermal resources in SE Poland : the Lublin trough
- 2021
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Ingår i: Geothermal Energy. - : SPRINGER. - 2195-9706. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- Although geothermal resources are practically independent of climate factors, those factors significantly condition the potential use of the Earth's natural heat resources. Unlike all the other factors limiting or facilitating the use of geothermal heat (like receivers' temperature expectation, financial issues or local regulations), climate factors remain immovable. Thus, climate remains the main factor influencing the effective use of geothermal resources. Volumes of sold energy, typical capacity factors and rapid changes in heat demand may all influence the financial and technological performance of an investment. In the current paper, climate factors are translated into heat demand based on historical data (meteorological and district heating logs) by means of a dedicated artificial neural network, and analysed in terms of possible constraints and facilitators that might affect the effective use of geothermal energy. The results of ANN simulation indicate that average and typical operation is expected without any turbulences, yet about 10% of operating hours may require additional technical measures, like peak source support, smart management and buffers in order to limit pumping ramp rate. With appropriate dimensioning and exploitation, capacity factors as high as 60% are available, proving the potential for financially and environmentally effective use of geothermal resources.
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| 8. |
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| 9. |
- Ciapala, Bartlomiej, et al.
(författare)
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The Potential of Wind Power-Supported Geothermal District Heating Systems-Model Results for a Location in Warsaw (Poland)
- 2019
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Ingår i: Energies. - : MDPI. - 1996-1073. ; 12:19
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Tidskriftsartikel (refereegranskat)abstract
- Geothermal heat is considered a sustainable energy source with significant global potential. Together with heat distribution networks, it can provide clean thermal energy to individual and commercial consumers. However, peaks in heat demand can require additional peaking sources at times. In this paper, we investigated how wind turbines can act as a peak energy source for a geothermal district heating system. We studied a model consisting of a geothermal heat source, a heat storage and wind power generator using historical weather data of Warsaw (Poland) and showed that wind power could increase the renewable share to supply a considerable heat demand compared to a geothermal heat source alone. The results indicate that wind power can be a suitable complement for a geothermal heat source to provide energy for heating. It is shown that a theoretical geo-wind-thermal storage based district heating network supplying 1000 m(2), which requires 100 W/m(2) at an outdoor temperature of -20 degrees C should have the following parameters: 4.8 MWh of thermal energy storage capacity, 45 kW of geothermal capacity and 5 kW of wind capacity. Such a system would ensure minimal wind curtailment, high utilization of geothermal source and high reliability of supply.
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| 10. |
- Javed, Muhammad Shahzad, et al.
(författare)
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A hybrid method for scenario-based techno-economic-environmental analysis of off-grid renewable energy systems
- 2021
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Ingår i: Renewable & sustainable energy reviews. - : PERGAMON-ELSEVIER SCIENCE LTD. - 1364-0321 .- 1879-0690. ; 139
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Tidskriftsartikel (refereegranskat)abstract
- Researchers have often overlooked the emissions problem during the suitable selection of renewable energy (RE) systems. Therefore, there is a need for an integrated framework that simultaneously considers the economic, technical and environmental criteria for the selection of the appropriate configuration. Firstly, a multi-objective optimization is performed using the epsilon- constraint method with a simulated annealing algorithm. Then a scenario-based method with a hybrid multi-criterion decision-making approach is used to rank all the available configurations. Five operating strategies are developed to make different configurations, i.e. battery only, pumped hydro storage (PHS), battery-diesel generator (DG), PHS-DG, and hybrid pumped-battery storage. A total of seven scenarios are made based on the weightage given to each main criterion. The study reveals that solar-wind-PHS-DG was the top-ranking alternative under four scenarios, solar-wind-PHS ranked first in two scenarios, and solar-wind-DG-battery got preference under the no-preference scenario; this shows that preferential selection (assigning a weighting to each criterion) significantly affects results. Emissions of all considered RE-based alternatives range from 0.072 to 0.148 kg (CO2 equivalent) per kWh of the served load. Furthermore, sensitivity analysis reveals that technical criteria conflict more with economic criteria than with environmental criteria. The impact of land requirements (an environmental sub-criterion) is visible in this study, indicating the high requirement of land for RE systems. The most appropriate configuration type is selected depending solely on the priorities defined by investors and policy-makers.
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