| 1. |
- Hodge, B. -MS., et al.
(författare)
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Addressing technical challenges in 100% variable inverter-based renewable energy power systems
- 2020
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Ingår i: Wiley Interdisciplinary Reviews. - : John Wiley and Sons Ltd. - 2041-8396 .- 2041-840X. ; 9:5
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Tidskriftsartikel (refereegranskat)abstract
- Rapidly increasing levels of variable inverter-based renewable energy sources (are quickly changing electric power systems and prompting questions about how the systems will be operated when renewable generation becomes the dominant technologies. In this article, we review the status of this shifting paradigm in power systems throughout the world. We then review the implications of this shift, focusing on the rising challenges, and we provide an overview and technology-readiness classifications of some proposed mitigation strategies. Finally, we highlight outstanding questions that will require solutions to reach these ultrahigh shares of variable inverter-based renewable energy sources.
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| 2. |
- Holttinen, H., et al.
(författare)
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Design and operation of power systems with large amounts of wind power production, IEA collaboration
- 2006
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Ingår i: European Wind Energy Conference and Exhibition 2006. - 9781622764679 ; , s. 156-165
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Konferensbidrag (refereegranskat)abstract
- New R&D collaboration on "Design and Operation of Power Systems with Large Amounts of Wind Power Production" has been formed in IEA Wind. The R&D task will collect and share information on the experience gained and the studies made on power system impacts of wind power, and review methodologies, tools and data used. This paper outlines the power system impacts of wind power, the national studies published and on-going and describes the goals of the international collaboration. There are dozens of studies made and ongoing related to cost of wind integration, however, the results are not easy to compare. An in-depth review of the studies is needed to draw conclusions on the range of integration costs for wind power. State-of-the art review process will seek for reasons behind the wide range of results for costs of wind integration - definitions for wind penetration, reserves and costs; different power system and load characteristics and operational rules; underlying assumptions on variability of wind etc.
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| 3. |
- Holttinen, H., et al.
(författare)
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Steps for a complete wind integration study
- 2013
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Ingår i: Proceedings of the Annual Hawaii International Conference on System Sciences. - 9780769548920 ; , s. 2261-2270
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Konferensbidrag (refereegranskat)abstract
- There have been many wind integration studies in recent years, and these efforts are expected to continue. Because power systems and data availability vary significantly, the results and methodologies used in these studies vary. This paper presents findings from international collaboration under IEAWIND Task 25 working towards Recommended Practices for Wind Integration studies. An overview of a complete wind integration study is presented as a flow chart. The setup of a study and main assumptions are important because they have a crucial impact on the results. The main steps in the simulations are presented with methodologies, which include the increase in reserve requirements, estimating impacts on other generation and balancing, capacity value of wind power and increase in transmission due to wind power.
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| 4. |
- Huertas-Hernando, D., et al.
(författare)
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Hydro power flexibility for power systems with variable renewable energy sources : An IEA Task 25 collaboration
- 2016
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Ingår i: Wiley Interdisciplinary Reviews. - : John Wiley & Sons. - 2041-8396 .- 2041-840X.
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Tidskriftsartikel (refereegranskat)abstract
- Hydro power is one of the most flexible sources of electricity production. Power systems with considerable amounts of flexible hydro power potentially offer easier integration of variable generation, e.g., wind and solar. However, there exist operational constraints to ensure mid-/long-term security of supply while keeping river flows and reservoirs levels within permitted limits. In order to properly assess the effective available hydro power flexibility and its value for storage, a detailed assessment of hydro power is essential. Due to the inherent uncertainty of the weather-dependent hydrological cycle, regulation constraints on the hydro system, and uncertainty of internal load as well as variable generation (wind and solar), this assessment is complex. Hence, it requires proper modeling of all the underlying interactions between hydro power and the power system, with a large share of other variable renewables. A summary of existing experience of wind integration in hydro-dominated power systems clearly points to strict simulation methodologies. Recommendations include requirements for techno-economic models to correctly assess strategies for hydro power and pumped storage dispatch. These models are based not only on seasonal water inflow variations but also on variable generation, and all these are in time horizons from very short term up to multiple years, depending on the studied system. Another important recommendation is to include a geographically detailed description of hydro power systems, rivers' flows, and reservoirs as well as grid topology and congestion.
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| 5. |
- Söder, Lennart, et al.
(författare)
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Experience and challenges with short-term balancing in European systems with large share of wind power
- 2012
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Ingår i: IEEE Transactions on Sustainable Energy. - 1949-3029. ; 3:4, s. 853-861
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Tidskriftsartikel (refereegranskat)abstract
- The amount of wind 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. Some areas are starting to experience very high penetration levels of wind and there have been many instances when wind power has exceeded 50% of the electrical energy production in some balancing areas. The aims of this paper are to show the increased need for balancing, caused by wind power in the minutes to hourly time scale, and to show how this balancing has been performed in some systems when the wind share was higher than 50%. Experience has shown that this is possible, but that there are some challenges that have to be solved as the amount of wind power increases.
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| 6. |
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| 7. |
- Holttinen, H., et al.
(författare)
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Design and operation of power systems with large amounts of wind power
- 2009
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Bok (refereegranskat)abstract
- There are already several power systems coping with large amounts of wind power. Hi h penetration of wind power has impacts that have to be manage through proper plant interconnection, integration, transmission planning, and system and market operations. This report is a summary of case studies addressing concerns about the impact of wind power.s variability and uncertainty on power system reliability and costs. The case studies summarized in this report are not easy to compare due to different methodology and data used, as well as different assumptions on the interconnection capacity available. Integration costs of wind power need to be compared to something, like the production costs or market value of wind power, or integration cost of other production forms. There is also benefit when adding wind power to power systems: it reduces the total operating costs and emissions as wind fossil fuels. Severalissues 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 working 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. From the investigated studies it follows that at wind penetrations of up to 20 % of gross demand (energy), system operating cost increases arising from wind variability and uncertainty amounted to about 1.4 ./MWh. This is 10 % or less of the wholesale value of the wind energy.
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| 8. |
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| 9. |
- Holttinen, H., et al.
(författare)
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State-of-the-art of design and operation of power systems with large amounts of wind power, summary of IEA wind collaboration
- 2007
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Ingår i: European Wind Energy Conference and Exhibition 2007, EWEC 2007. - 9781622764686 ; , s. 489-499
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Konferensbidrag (refereegranskat)abstract
- An international forum for exchange of knowledge of power system impacts of wind power has been formed under the IEA Implementing Agreement on Wind Energy. The task "Design and Operation of Power Systems with Large Amounts of Wind Power" is analysing existing case studies from different power systems.There are a multitude of studies made and ongoing related to cost of wind integration. However, the results are not easy to compare. This paper summarises the results from 15 case studies.
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| 10. |
- Holttinen, H., et al.
(författare)
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System Impact Studies for Near 100% Renewable Energy Systems Dominated by Inverter Based Variable Generation
- 2022
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Ingår i: IEEE Transactions on Power Systems. - : Institute of Electrical and Electronics Engineers (IEEE). - 0885-8950 .- 1558-0679. ; 37:4, s. 3249-3258
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Tidskriftsartikel (refereegranskat)abstract
- The demand for low carbon energy calls for close to 100% renewable power systems, with decarbonization of other energy sectors adding to the anticipated paradigm shift. Rising levels of variable inverter-based renewable energy sources (VIBRES) are prompting questions about how such systems will be planned and operated when variable renewable generation becomes the dominant technology. Here, we examine the implications of this paradigm shift with respect to planning, operation and system stability, also addressing the need for integration with other energy vectors, including heat, transport and Power-to-X. We highlight the knowledge gaps and provide recommendations for improved methods and models needed as power systems transform towards 100% VIBRES.
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| 11. |
- Keane, A., et al.
(författare)
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Capacity value of wind power
- 2011
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Ingår i: IEEE Transactions on Power Systems. - 0885-8950 .- 1558-0679. ; 26:2, s. 564-572
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Tidskriftsartikel (refereegranskat)abstract
- Power systems are planned such that they have adequate generation capacity to meet the load, according to a defined reliability target. The increase in the penetration of wind generation in recent years has led to a number of challenges for the planning and operation of power systems. A key metric for generation system adequacy is the capacity value of generation. The capacity value of a generator is the contribution that a given generator makes to generation system adequacy. The variable and stochastic nature of wind sets it apart from conventional energy sources. As a result, the modeling of wind generation in the same manner as conventional generation for capacity value calculations is inappropriate. In this paper a preferred method for calculation of the capacity value of wind is described and a discussion of the pertinent issues surrounding it is given. Approximate methods for the calculation are also described with their limitations highlighted. The outcome of recent wind capacity value analyses in Europe and North America, along with some new analysis, are highlighted with a discussion of relevant issues also given.
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| 12. |
- Korpas, M., et al.
(författare)
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Addressing Market Issues in Electrical Power Systems with Large Shares of Variable Renewable Energy
- 2022
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Ingår i: International Conference on the European Energy Market, EEM. - : Institute of Electrical and Electronics Engineers (IEEE).
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Konferensbidrag (refereegranskat)abstract
- This paper reports recent findings from IEA Wind TCP Task 25, which compiles international experiences and research related to large-scale integration of wind and other renewable energy. In the paper, we address the main challenges for market integration of variable renewable energy, relating to price formation, cost recovery, balancing and other grid services. The paper gives an overview of recent scenario studies on electricity price impacts of (1) various generation, energy storage and demand types in different markets, and (2) different market designs and energy/climate policies. Studying markets with very high shares of variable renewable energy requires an improved set of analysis tools for forecasting market outcomes, estimating flexibility needs and sources, and assessing resource adequacy. Key market features need to be investigated within these improved analytical capabilities for systems transitioning to high shares of variable renewable energy, storage and flexible demand. System services that can be supported by markets will likely need to be revisited. Finally, this paper identifies open questions and suggested future market design work for supporting systems with very high shares of variable renewable energy, which are to be addressed in follow-up work of Task 25 collaborative research.
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| 13. |
- Milligan, M., et al.
(författare)
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Capacity value assessments of wind power
- 2016
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Ingår i: Wiley Interdisciplinary Reviews. - : John Wiley & Sons. - 2041-8396 .- 2041-840X.
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Tidskriftsartikel (refereegranskat)abstract
- This article describes some of the recent research into the capacity value of wind power. With the worldwide increase in wind power during the past several years, there is increasing interest and significance regarding its capacity value because this has a direct influence on the amount of other (nonwind) capacity that is needed. We build on previous reviews from IEEE and IEA Wind Task 25a and examine recent work that evaluates the impact of multiple-year data sets and the impact of interconnected systems on resource adequacy. We also provide examples that explore the use of alternative reliability metrics for wind capacity value calculations. We show how multiple-year data sets significantly increase the robustness of results compared to single-year assessments. Assumptions regarding the transmission interconnections play a significant role. To date, results regarding which reliability metric to use for probabilistic capacity valuation show little sensitivity to the metric. For further resources related to this article, please visit the WIREs website.
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| 14. |
- Milligan, M., et al.
(författare)
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Market designs for high levels of variable generation
- 2014
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Ingår i: IEEE Power and Energy Society General Meeting.
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Konferensbidrag (refereegranskat)abstract
- Variable renewable generation is increasing in penetration in modern power systems, leading to higher variability in the supply and price of electricity as well as lower average spot prices. This raises new challenges, particularly in ensuring sufficient capacity and flexibility from conventional technologies. As the fixed costs and lifetimes of electricity generation investments are significant, designing markets and regulations which ensure efficient integration of renewable generation is a significant challenge. This panel presentation reviews the state of play in the USA and Europe with regard to these issues and considers new developments in both regions.
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| 15. |
- Milligan, M., et al.
(författare)
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Market structures to enable efficient wind and solar power integration
- 2012
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Ingår i: Power and Energy Society General Meeting, 2012 IEEE. - : IEEE. - 9781467327275 ; , s. 6345591-
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Konferensbidrag (refereegranskat)abstract
- The development of large amounts of wind and/or solar energy will have an impact on bulk electricity markets. These variable generation sources increase the level of variability and uncertainty that the power system operator must manage. In this paper we discuss the impact that electricity markets have on the wind producer, using examples from the Nordic system. We also describe two market structures that will help induce both the needed flexibility, whether from generation or load, and sufficient capacity. We also provide some general guidelines for market design and simple tests that can help identify how a proposed market would function. We close with suggestions for future research.
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| 16. |
- Milligan, M., et al.
(författare)
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Preface : Wind Power Myths Debunked
- 2012
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Ingår i: Wind Power in Power Systems, Second Edition. - : John Wiley and Sons. ; , s. 7-20
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Bokkapitel (refereegranskat)abstract
- Wind power use has grown significantly in recent years. As power system planners, investors, and other stakeholders evaluate the development of wind power plants, many questions about wind power plant operational characteristics have arisen. These questions range from asking whether wind power plants require storage, to how fast can wind power plants' output fall to zero. Recent experience in operating power systems with increasing levels of wind power, along with a significant body of analysis, has provided answers to many of these questions. In this chapter, we discuss many of these key questions and answers drawing on international experience and analysis of wind power plant operations.
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| 17. |
- Söder, Lennart, et al.
(författare)
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On methodology for modelling wind power impact on power systems
- 2008
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Ingår i: International Journal of Global Energy Issues. - 0954-7118 .- 1741-5128. ; 29:1-2, s. 181-198
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Tidskriftsartikel (refereegranskat)abstract
- There is a continuous discussion going on concerning the integration cost of wind power. The integration cost can, for example, be defined as the extra costs in the rest of the system when wind power is introduced, compared with the situation without wind power. The result of the studies depends on both parameters and the method used. The aim of this paper is to structure the methods in order to get some understanding on the impact of different modelling approaches. In general, it can be noted that approximations are always needed since the integration of wind power includes so many complexities including stability of power systems, grid codes, market behaviour, uncertainties and trading possibilities. AU these items have to be considered in both the wind power case and in the reference case to obtain an estimation of the integration cost.
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