| 1. |
- Jurasz, J., et al.
(författare)
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Complementarity of wind and solar power in North Africa : Potential for alleviating energy droughts and impacts of the North Atlantic Oscillation
- 2024
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Ingår i: Renewable & sustainable energy reviews. - : Elsevier Ltd. - 1364-0321 .- 1879-0690. ; 191
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Tidskriftsartikel (refereegranskat)abstract
- With growing gas and oil prices, electricity generation based on these fossil fuels is becoming increasingly expensive. Furthermore, the vision of natural gas as a transition fuel is subject to many constraints and uncertainties of economic, environmental, and geopolitical nature. Consequently, renewable energies such as solar and wind power are expected to reach new records of installed capacity over the upcoming years. Considering the above, North Africa is one of the regions with the largest renewable resource potential globally. While extensively studied in the literature, these resources remain underutilized. Thus, to contribute to their future successful deployment and integration with the power system, this study presents a spatial and temporal analysis of the nature of solar and wind resources over North Africa from the perspective of energy droughts. Both the frequency and maximal duration of energy droughts are addressed. Both aspects of renewables’ variable nature have been evaluated in the North Atlantic Oscillation (NAO) context. The analysis considers the period between 1960 and 2020 based on hourly reanalysis data (i.e., near-surface shortwave irradiation, wind speed, and air temperature) and the Hurrel NAO index. The findings show an in-phase relationship between solar power and winter NAO index, particularly over the coastal regions in western North Africa and opposite patterns in its eastern part. For wind energy, the connection with NAO has a more zonal pattern, with negative correlations in the north and positive correlations in the south. Solar energy droughts dominate northern Tunisia, Algeria, and Morocco, while wind energy droughts mainly occur in the Atlas Mountains range. On average, solar energy droughts tend not to exceed 2–3 consecutive days, with the longest extending for five days. Wind energy droughts can be as prolonged as 80 days (Atlas Mountains). Hybridizing solar and wind energy reduces the potential for energy droughts significantly. At the same time, the correlation between their occurrence and the NAO index remains low. These findings show the potential for substantial resilience to inter-annual climate variability, which could benefit the future stability of renewables-dominated power systems.
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| 2. |
- Kapica, J., et al.
(författare)
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The potential impact of climate change on European renewable energy droughts
- 2024
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Ingår i: Renewable & sustainable energy reviews. - : Elsevier Ltd. - 1364-0321 .- 1879-0690. ; 189
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Tidskriftsartikel (refereegranskat)abstract
- The daily, seasonal, and interannual variability of solar and wind resources is well-documented, based on evidence from multi-decadal meteorological time series. However, with the growing share of non-dispatchable renewable-based power sources (e.g., wind and solar power), the stable operation of the power system could be undermined by prolonged periods of low availability of these resources. Consequently, this may result in extremely high prices in the energy market or even a power system blackout. This study analyzes the performance of solar, wind, and solar-wind hybrid systems in Europe based on eight regional climate models, considering two possible climate change projections. The resource availability has been evaluated based on the energy drought concept. The total duration of droughts is calculated using daily capacity factors covering the years 1970–2020 (reference period) and 2048–2098 (future period), considering sub-national regions across the whole of Europe. In general, the chosen climate models show a more significant agreement in the occurrence of energy droughts for northern and southern Europe compared to its central part. Assessing the potential for renewable energy droughts is critical to maintaining secure and reliable power system operation in both the present and future climate.
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| 3. |
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| 4. |
- Elkadeem, M. R., et al.
(författare)
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Geospatial-assisted multi-criterion analysis of solar and wind power geographical-technical-economic potential assessment
- 2022
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Ingår i: Applied Energy. - : Elsevier Ltd. - 0306-2619 .- 1872-9118. ; 322
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Tidskriftsartikel (refereegranskat)abstract
- Amid the increasing electricity demand, energy crisis and pollution, the transition to renewable energy (RE) is becoming a preoccupation and major global challenge due to the multidimensional and intricate problem of RE planning. In Egypt, about 90% of gross power generation comes from carbon-intensive power plants (natural gas and coal). Here, we propose a novel geospatial-decision-making model aimed at geographical-technical–economic potential mapping and assessment of solar photovoltaic (PV) and onshore wind turbine (WT) power plants at a high level of resolution (1 km2) in Egypt. We identify the locations suitable for PV and WT development considering sixteen restrictive and contradictory evaluation criteria. These locations have been further analyzed to estimate how much energy generation is available and at what energy cost. The analysis identifies Middle-Upper Egypt and Suez Canal as hosting the majority of highly suitable locations for PV and WT power plants, respectively. Our finding reveals that the proper planning on RE projects at the proposed optimum locations could support the country's energy mix with a sizable 32% share of the projected country's electricity consumption from PV and 50% share from WT, by 2030. Furthermore, we show that the investment opportunities of PV and WT generation are potentially attractive with affordable competitive prices estimated at 57.84 $/MWh and 32.36 $/MWh, respectively, against conventional generation for today and the future. We anticipate that our results will provide valuable support in realizing Egypt's vision for sustainable electricity generation and in keeping abreast of the global transformation in power systems being witnessed. Ultimately, the method's relevance extends beyond the geographical boundaries of the present territory; it features a strategic, clear and reproducible approach that may be applied to a larger area or continent, provided the necessary input data and criteria are introduced.
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| 5. |
- Gao, Shuang, et al.
(författare)
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Potential benefits from participating in day-ahead and regulation markets for CHPs
- 2022
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Ingår i: Applied Energy. - : Elsevier Ltd. - 0306-2619 .- 1872-9118. ; 306:A
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Tidskriftsartikel (refereegranskat)abstract
- A combined heat and power plant (CHP) has the ability to provide ancillary services and therefore, can contribute to the improvement of flexibility and reliability of the power system. To motivate CHPs to provide flexibility services, this work investigated the potential benefit for CHPs from participating simultaneously in day-ahead and frequency regulation markets. A new CHP model was proposed, which considers both heat recovery from flue gas condensation and thermal energy storage. Based on the multi-market optimization using real market prices, it can be concluded that providing the frequency regulation service in addition to day-ahead trading can increase the annual profit of CHPs, which was 2.75% for the studied CHP. Meanwhile, the benefit was clearly affected by the heat demand as both high and low heat demand seasons (e.g. in winter and summer) can limit the flexibility provided by the CHP. In addition, the sensitivity analysis was carried out to assess the impacts of key factors, including electricity price, heat demand, cost of electricity, and bid size for frequency reserve services, on the benefit from the participation in both markets. The price difference between the day-ahead and frequency regulation markets and the cost of electricity generation were found to have clear impacts on the benefit of the CHP.
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| 6. |
- Jurasz, J., et al.
(författare)
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On the impact of load profile data on the optimization results of off-grid energy systems
- 2022
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Ingår i: Renewable & sustainable energy reviews. - : Elsevier Ltd. - 1364-0321 .- 1879-0690. ; 159
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Tidskriftsartikel (refereegranskat)abstract
- Access to electricity via large scale power grids is seen as one of the solutions for a fully renewable power system. However, it remains a huge technical, economical, and geopolitical challenge. In the meantime, millions of people across the world have none or limited access to electricity and quite often to rely on autonomous solutions such as diesel generators. With the decreasing cost of renewable energy generation technologies in recent years, one could observe a simultaneous increase in studies dedicated to optimal sizing of renewable off-grid systems. Many of these studies rely on the usage of typical daily load profiles to model the electricity demand, sometimes enhanced with seasonal or random components. Such approaches tend to overlook the existing potential case-specific correlation between availability of renewable energy and energy demand and in particular the natural variability of the load in terms of its extreme values or ramp rates. The objective of this study is to investigate the impact of different types of load input data (for instance real load, monthly adjusted typical load, and typical daily load) on the cost of energy provided by off-grid PV-battery systems supplying various loads with different reliability levels. For this purpose, we determine the optimal capacity of PV-battery systems based on commonly used energy management strategies and optimization algorithms. The analysis of the obtained results indicates that, on average, using daily load profiles tends to underestimate the cost by 1.2% points (pp) for a system with 100% reliability and by over 5 pp for a system characterized by 95% reliability. Using monthly adjusted typical daily load profiles leads to slight differences compared to the results obtained by using real load as input. Although the obtained average values indicate a tendency of underestimating the energy cost, some outliers have been also observed reaching values of up to 15% of overestimating the cost of energy.
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