| 1. |
- Bird, Lori, et al.
(författare)
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Wind and solar energy curtailment : A review of international experience
- 2016
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Ingår i: Renewable & sustainable energy reviews. - : Elsevier. - 1364-0321 .- 1879-0690. ; 65, s. 577-586
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Forskningsöversikt (refereegranskat)abstract
- Greater penetrations of variable renewable generation on some electric grids have resulted in increased levels of curtailment in recent years. Studies of renewable energy grid integration have found that curtailment levels may grow as the penetration of wind and solar energy generation increases. This paper reviews international experience with curtailment of wind and solar energy on bulk power systems in recent years, with a focus on eleven countries in Europe, North America, and Asia. It examines levels of curtailment, the causes of curtailment, curtailment methods and use of market based dispatch, as well as operational, institutional, and other changes that are being made to reduce renewable energy curtailment.
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| 2. |
- Hannele, Holttinen, et al.
(författare)
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Impacts of large amounts of wind power on design and operation of power systems, results of IEA collaboration
- 2009
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Ingår i: 8th International Workshop on LargeScale Integration of Wind Power into Power Systems as well as on Transmission Networks of Offshore Wind Farms.
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Konferensbidrag (refereegranskat)abstract
- IEA WIND R&D Task 25 on “Design and Operation of Power Systems with Large Amounts of Wind Power” collects and shares information on wind power impacts on power systems, with analyses and guidelines on methodologies. There are dozens of studies made and ongoing related to wind integration, however, the results are not easy to compare. In the stateoftheart report (October, 2007), and the final report of the 3 years period (July, 2009) the most relevant wind power grid integration studies have been analysed especially regarding methodologies and input data. Several issues that impact on the amount of wind power that can be integrated have been identified. Large balancing areas and aggregation benefits of large areas help in reducing the variability and forecast errors of wind power as well as help in pooling more cost effective balancing resources. System operation and functioning electricity markets at less than dayahead time scales help reduce forecast errors of wind power. Transmission is the key to aggregation benefits, electricity markets and larger balancing areas. Best practices in wind integration studies are described. There is also benefit when adding wind power to power systems: it reduces the total operating costs and emissions as wind replaces fossil fuels and this should be highlighted more in future studies.
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| 3. |
- Hodge, Bri-Mathias, et al.
(författare)
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Wind Power Forecasting Error Distributions : An International Comparison
- 2012
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Konferensbidrag (refereegranskat)abstract
- Wind power forecasting is essential for greater penetration of wind power into electricity systems. Because no wind forecasting system is perfect, a thorough understanding of the errors that may occur is a critical factor for system operation functions, such as the setting of operating reserve levels. This paper provides an international comparison of the distribution of wind power forecasting errors from operational systems, based on real forecast data. The paper concludes with an assessment of similarities and differences between the errors observed in different locations.
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| 4. |
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| 5. |
- Holttinen, Hannele, et al.
(författare)
-
Impacts of large amounts of wind power on design and operation of power systems, results of IEA collaboration
- 2011
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Ingår i: Wind Energy. - : Wiley. - 1095-4244 .- 1099-1824. ; 14:2, s. 179-192
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Tidskriftsartikel (refereegranskat)abstract
- There are dozens of studies made and ongoing related to wind integration. However, the results are not easy to compare. IEA WIND R&D Task 25 on 'Design and Operation of Power Systems with Large Amounts of Wind Power' collects and shares information on wind generation impacts on power systems, with analyses and guidelines on methodologies. In the state-of-the-art report (October, 2007), and the final report of the 3 years period (July, 2009) the most relevant wind power grid integration studies have been analysed especially regarding methodologies and input data. Several issues that impact on the amount of wind power that can be integrated have been identified. Large balancing areas and aggregation benefits of wide areas help in reducing the variability and forecast errors of wind power as well as help in pooling more cost effective balancing resources. System operation and functioning electricity markets at less than day-ahead time scales help reduce forecast errors of wind power. Transmission is the key to aggregation benefits, electricity markets and larger balancing areas. Best practices in wind integration studies are described. There is also benefit when adding wind power to power systems: it reduces the total operating costs and emissions as wind replaces fossil fuels and this should be highlighted more in future studies.
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| 6. |
- Holttinen, Hannele, et al.
(författare)
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The flexibility workout : Managing variable resources and assessing the need for power system modification
- 2013
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Ingår i: IEEE Power & Energy Magazine. - 1540-7977. ; 11:6, s. 53-62
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Tidskriftsartikel (refereegranskat)abstract
- Power systems have been designed and operated so that the demand for electricity can be met at all times and under a variety of conditions. Depending on the season, the climate, and the weather, demand can fluctuate significantly over a single day, week, or month. For example, in France the extensive use of electricity to generate heating creates a relationship between increase in electricity demand and decrease in temperature that amounts to close to 2,400 MW/°C. In addition to meeting the variability requirements, there is always some inherent uncertainty about future demand and the future availability of generators. The power system must thus be able to manage both variability and uncertainty.
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| 7. |
- 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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| 8. |
- Kiviluoma, Juha, et al.
(författare)
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Index for wind power variability
- 2014
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Ingår i: Proceedings of 13th International Workshop on Large-Scale Integration of Wind Power into Power Systems as well as on Transmission Networks for Offshore Wind Power (WIW 2014). - 9783981387094
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Konferensbidrag (refereegranskat)abstract
- Variability of large scale wind power generation isdependent on several factors: characteristics of installed windpower plants, size of the area where the plants are installed,geographic dispersion within that area and its weatherregime(s). Variability can be described by ramps in powergeneration, i.e. changes from time period to time period. Givenenough data points, it can be described with a probabilitydensity function. This approach focuses on two dimensions ofvariability: duration of the ramp and probability distribution.This paper proposes an index based on these two dimensionsto enable comparisons and characterizations of variabilityunder different conditions. The index is tested with real, largescale wind power generation data from several countries.Considerations while forming an index are discussed, as wellas the main results regarding what the drivers of variabilityexperienced for different data.
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| 9. |
- 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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| 10. |
- Nordström, Henrik, et al.
(författare)
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Strategies for Continuous Balancing in Future Power Systems with High Wind and Solar Shares
- 2023
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Ingår i: Energies. - : MDPI AG. - 1996-1073. ; 16:14
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Forskningsöversikt (refereegranskat)abstract
- The use of wind power has grown strongly in recent years and is expected to continue to increase in the coming decades. Solar power is also expected to increase significantly. In a power system, a continuous balance is maintained between total production and demand. This balancing is currently mainly managed with conventional power plants, but with larger amounts of wind and solar power, other sources will also be needed. Interesting possibilities include continuous control of wind and solar power, battery storage, electric vehicles, hydrogen production, and other demand resources with flexibility potential. The aim of this article is to describe and compare the different challenges and future possibilities in six systems concerning how to keep a continuous balance in the future with significantly larger amounts of variable renewable power production. A realistic understanding of how these systems plan to handle continuous balancing is central to effectively develop a carbon-dioxide-free electricity system of the future. The systems included in the overview are the Nordic synchronous area, the island of Ireland, the Iberian Peninsula, Texas (ERCOT), the central European system, and Great Britain.
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