The high-voltage direct current (HVDC) links connecting the Finnish grid to Sweden and Estonia were at good level in terms of technical availability in 2021.
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The interconnectors ensure the security of transmission to consumption in Finland.
Statistics on Nordic and Baltic links for 2021 have been published on Fingrid's website. The statistics provide information on the transmission, availability and outages of direct current connections between different countries.
The technical availability of the individual links connected to Finland (taking also into account power limitations) were:
EstLink1 96.6%, EstLink2 99.6%, Fenno-Skan1 94.8% and Fenno-Skan2 82.5%. The clearly weaker availability of the Fenno-Skan2 link was mainly due to the limitations of Sweden's internal transmission grid. The other links were among the best links in terms of technical availability.
The Nordic and Baltic electricity markets used most the FI - EE market connection between Finland and Estonia in 2021. The utilisation rate was 77 (75) percent of the total capacity, corresponding to 6.8 (6.6) terawatt hours. The transmission was almost entirely (99%) export to Estonia.
The utilisation rate of the FI - SE3 market connection between Finland and Sweden was 68 (85) percent of the total capacity, corresponding to 7.1 (8.9) terawatt hours. 88 percent of the transmission was import to Finland.
For the third year in a row, the Fenno-Skan1 link had the highest utilisation rate of all HVDC links in the Baltic Sea Region, 92 (97) percent of the total capacity.
The second-best utilisation rate had EstLink2 with 87 (85) %. The utilisation rate of the EstLink1 link was 58 (57) % and the Fenno-Skan2 link was 56 (78) %.
EstLink 1 connection is regularly used also to support the frequency of the Nordic power system. Fingrid purchases part of the frequency containment reserves from Estonian HVDC links. In addition, EstLink 1 converter stations are utilised as part of the voltage regulation and reactive power management of the Finnish and Estonian main grids. This activity will help the electricity transmission of both countries to operate as securely as possible.
In 2021, the technical capacity of Finland's HVDC links was out of service due to disturbances and maintenance work on average only 2.2% (1.8%) of the hours throughout the year, i.e. approximately 190 hours (160 hours).
The extraordinary circumstances prevailing in the energy markets have raised uncertainties around the availability of electricity, which are expected to lead to scarcity in the supply of reserves used to manage the power balance in the electricity system in the coming months. All the balancing resources capable of contributing to the reserve markets are requested to make themselves available. In addition, Fingrid is promoting market changes to facilitate the process of offering reserves as of the latter part of the year.
Fingrid uses various reserve products to balance out normal fluctuations between electricity consumption and production and to restore the balance between production and consumption in the event of a disturbance, such as a sudden fault in a power plant.
The amount of supply in the reserve market has decreased in recent months due to the extraordinary circumstances prevailing in the energy markets, and there may be significant scarcity in the availability of reserves from time to time in the coming months. Without sufficient reserves, disturbances are more likely to lead to electricity shortages, making it necessary to disconnect consumers momentarily.
In order to ensure the security of the electricity system in the coming winter, it is crucial for all balancing resources to participate in the reserve market.
The commissioning of the Olkiluoto 3 nuclear power plant, scheduled for the end of the year, will increase the dimensioning fault of the power system of Finland from the current 1,100 MW cross-border line fault to 1,300 MW), which will increase the need for up-regulation capacity in the manual Frequency Restoration Reserve (mFRR) that can be activated within 15 minutes. Fingrid ensures that the available reserves are at least equal to the Finnish dimensioning fault so that the power system can be restored to normal in the event of the largest possible individual failure.
At the beginning of December 2022, day ahead hourly market will replace weekly procurements of balancing capacity. This will make it easier to offer balancing capacity, as the visibility of the capacity on offer will improve as purchases are made closer to the time of delivery, and the bid volumes in hourly markets can fluctuate at different times of the day.
In addition, Fingrid is working on an amendment to the terms and conditions for the balancing power market (also known as the mFRR energy market) to expand the adoption of 1 MW bids. In the future, a balancing service provider could submit up to five balancing bids under 5 MW in each direction instead of the current limit of one such balancing bid. ■