Design and operation of energy systems with large amounts of variable generation: Final summary report, IEA Wind TCP Task 25

Hannele Holttinen, Juha Kiviluoma, Niina Helistö, Thomas Levy, Nickie Menemenlis, Liu Jun, Nicolaos Cutululis, Matti Koivisto, Kaushik Das, Antje Orths, Peter Børre Eriksen, Emmanuel Neau, Jean-Yves Bourmaud, Jan Dobschinski, Christoph Pellinger, Serafin von Roon, Andrej Guminski, Damian Flynn, Enrico Maria Carlini, Yoh YasudaRyuya Tanabe, Simon Watson, Arjen van der Meer, Germán Morales-España, Magnus Korpås, Til Kristian Vrana, Ana Estanqueiro, António Couto, Bernardo Silva, Sergio Martín Martínez, Lennart Söder, Goran Strbac, Danny Pudjianto, Spyros Giannelos, Bethany Frew, Bri-Mathias Hodge, Shahil Shah, J. Charles Smith, Debbie Lew, Mark O'Malley, Vasiliki Klonari

Research output: Book/ReportReport


This report summarises findings on wind integration from the 17 countries or
sponsors participating in the International Energy Agency Wind Technology
Collaboration Programme (IEA Wind TCP) Task 25 from 2006–2020. Both real
experience and studies are reported. Many wind integration studies incorporate
solar energy, and most of the results discussed here are valid for other variable
renewables in addition to wind.

The national case studies address several impacts of wind power on electric
power systems. In this report, they are grouped under long-term planning issues
and short-term operational impacts. Long-term planning issues include grid
planning and capacity adequacy. Short-term operational impacts include
reliability, stability, reserves, and maximising the value of wind in operational
timescales (balancing related issues). The first section presents the variability and
uncertainty of power system-wide wind power, and the last section presents
recent studies toward 100% shares of renewables. The appendix provides a
summary of ongoing research in the national projects contributing to Task 25 for

The design and operation of power and energy systems is an evolving field. As
ambitious targets toward net-zero carbon energy systems are announced
globally, many scenarios are being made regarding how to reach these future
decarbonized energy systems, most of them involving large amounts of variable
renewables, mainly wind and solar energy. The secure operation of power
systems is increasingly challenging, and the impacts of variable renewables, new
electrification loads together with increased distribution system resources will
lead to somewhat different challenges for different systems. Tools and methods
to study future power and energy systems also need to evolve, and both shortterm
operational aspects (such as power system stability) and long-term aspects
(such as resource adequacy) will probably see new paradigms of operation and
design. The experience of operating and planning systems with large amounts of
variable generation is accumulating, and research to tackle the challenges of
inverter-based, nonsynchronous generation is on the way. Energy transition and
digitalization also bring new flexibility opportunities, both short and long term.
Original languageEnglish
PublisherVTT Technical Research Centre of Finland
Number of pages195
ISBN (Electronic)978-951-38-8757-5
Publication statusPublished - 2021
MoE publication typeD4 Published development or research report or study

Publication series

SeriesVTT Technology


  • grid integration
  • wind integration
  • electricity markets
  • flexibility
  • capacity value
  • grid reinforcement


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