Strengthening system stability through Nordic cooperation

The new ancillary service FFR will provide means for dealing with a growing problem in the Nordic power system; Decreasing system inertia which in a case of e.g. a large loss of production leads to a rapid and deep drop in frequency. The introduction of FFR is a result of a Nordic TSO development project, Inertia 2020.

A common Nordic press release. By 2018, the Nordic Transmission System Operators (TSOs) had identified a worrying trend towards decreasing system inertia. This due to changes in the power system related to the transition towards non-synchronised weather-dependent energy production. The project Inertia 2020 was initiated to propose mitigations to the decreasing system inertia.

Occasionally, the inertia level is so low that the current frequency containment reserves cannot guarantee frequency stability after an incident. This usually occurs in situations with low proportion of production from synchronous generators in combination with a high proportion of wind power and import. Situations like this can occur during summer and during hydrological dry years.

The main objective of the Nordic TSO project Inertia 2020 was to secure transient frequency stability for the Nordic power system in cases with low system inertia where FCR-D is not fast enough to handle an occurred large incident independently. As a solution, the project developed specifications for the new reserve Fast Frequency Reserve, FFR.

The Nordic TSOs have started to use the results from Inertia 2020. Implementation and procurement of FFR in the Nordic power system will start this year. Inertia 2020 is now completed and further development transferred to ordinary TSO operations.

Information on the procurement of FFR in Denmark (DK2) can be found here: Resultater for FFR

For more information on the technical requirements for FFR and design of the requirements, please see the findings from the project Technical Requirements for FFR - external document & FFR Design Requirements - external document or have a look at the document for prequalification: Prequalification and test


For more information, please contact:

Energinet: Thomas Dalgas Rasmussen,, +4523460422

Fingrid: Mikko Kuivaniemi,, +358 30 395 5188

Statnett: Jon Nerbø Ødegård,, +47 23903178

Svenska kraftnät: Therese Fahlberg,, +46 10 475 80 71 or Henrik Ekestam,, +46 10 475 86 53

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