| 1. |
- Huertas-Hernando, Daniel, et al.
(författare)
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Hydropower Flexibility for Power Systems with Variable Renewable Energy Sources: An IEA Task 25 Collaboration
- 2019
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Ingår i: Advances in Energy Systems. - : Wiley. ; , s. 385-405
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- In order to effectively utilize hydro production flexibility, a sufficient amount of transmission capacity has to be available between the hydro-dominated part of the system and the part that requires operational flexibility. This chapter starts with a rough categorization of “base” hydropower flexibility, investigating the types of hydropower plants installed in power systems today. The “effective” hydropower flexibility available to support the integration of variable generation is a far more complex and case-specific aspect. It is discussed through national experiences. The chapter presents potential developments that would increase the participation of hydropower and discuss the ensuing challenges. Modeling a flow-based hydro system is a complex exercise, as is modeling the power system. Especially important is the correct assessment of hydropower flexibility to support power systems with a large share of variable generation (VG) and its value for storage. With increasing uncertainty and variability, a stochastic scheduling approach should yield lower costs.
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| 2. |
- Kiviluoma, Juha, et al.
(författare)
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Variability in Large-Scale Wind Power Generation
- 2016
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Ingår i: Wind Energy. - : John Wiley & Sons. - 1095-4244 .- 1099-1824. ; 19:9, s. 1649-1665
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Tidskriftsartikel (refereegranskat)abstract
- The article demonstrates the characteristics of wind power variability and net load variability in multiple power systems based on real data from multiple years. Demonstrated characteristics include probability distribution for different ramp durations, seasonal and diurnal variability, and low net load events. In some characteristics the power systems are different, but in others they are significantly similar. Somewhat surprisingly there seems to be no straightforward correlation between wind power penetration level and variability. As long as there are several wind power plants with enough geographical spread, most of the smoothing impact is captured. Wind power variability is mainly explained by the extent of geographical spread, but also higher capacity factor causes higher variability. It was also shown how wind power ramps are auto correlated and dependent on the operating output level. In most cases wind power did not have strong diurnal or seasonal variations in the variability. However, there can be exceptions depending on the latitude and on the local characteristics of the wind resource.
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| 3. |
- Milligan, Michael, et al.
(författare)
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Capacity Value Assessments of Wind Power
- 2019
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Ingår i: Advances in Energy Systems. - : Wiley-Blackwell. ; , s. 369-384
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- This chapter describes some of the recent research into the capacity value of wind power. It builds on previous reviews from IEEE and International Energy Agency (IEA) Wind Task 25, and examines recent work that evaluates the impact of multiple-year data sets and the impact of interconnected systems on resource adequacy. The chapter provides examples that explore the use of alternative reliability metrics for wind capacity value calculations. It shows how multiple-year data sets significantly increase the robustness of results compared to single-year assessments. The preferred method for assessing the capacity value of wind and solar generation is a probabilistic approach grounded in the well-known loss of load probability (LOLP) and related reliability metrics. While reliability-based methods are widely accepted and provide accurate measures of wind and solar capacity values, they require detailed system data and can be computationally expensive to evaluate.
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| 4. |
- Söder, Lennart, 1956-, et al.
(författare)
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Comparison of Integration Studies of 30-40 percent Energy Share from Variable Renewable Sources
- 2017
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Ingår i: 16th International Workshop on Large-Scale Integration of Wind Power into Power Systems as well as on Transmission Networks for Offshore Wind Power Plants, Berlin, 2017, article id WIW17-049.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The amount of wind and solar power in the world is quickly increasing. The background for this development is improved technology, decreased costs for the units, and increased concern regarding environmental problems of competing technologies such as fossil fuels. For the future there are large possibilities for increasing shares. However there have been questions raised concerning the challenges of integrating larger shares of variable renewable power such as wind and solar power. Because of this many studies have been performed concerning larger amounts of variable generation for different regions in the world. The aim of this paper is to compare seven of these ones in order to identify general challenges and results as well as the connection between used method and results.
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| 5. |
- Söder, Lennart, 1956-, et al.
(författare)
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Wind Generation in Adequacy Calculations and Capacity Markets in Different Power System Control Zones
- 2018
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Ingår i: 17th International Wind Integration Workshop, Stockholm, 17-19 October 2018.
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Konferensbidrag (refereegranskat)abstract
- Generation capacity adequacy is a major issue in most power systems, but there are many approaches which canbe assessed. Power system planners often define target values for the capacity adequacy, which may be achieved through capacity markets/auctions, capacity reserves, or capacity purchases. Wind power contributes to the generation capacity adequacy of the power system since there is a possibility that wind power will generate in high load situations and thereby decreases the risk of generation capacity deficit compared tothe system without this source. The contribution is probabilistic– as it is with any other source, since nothing is 100% reliable - but the capacity value of wind power is significantly smaller compared to the capacity value of conventional fossil-fueled plants.In this article, an overview of the fundamental challenges inthe regulation of capacity adequacy as well as how wind poweris treated in some selected existing jurisdictions is presented.The jurisdictions that are included are Sweden, Great Britain,France, Ireland, United States (PJM), Finland, Portugal, SpainNorway and Denmark.
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