High-voltage direct current links connecting Finland to Sweden and Estonia reliable and extensively utilised
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. 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.
Connections reliable and in efficient use
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).
Figures for 2020 in parentheses.
The statistics can be downloaded here.
Markku Piironen, Fingrid Oyj
E-mail addresses: firstname.lastname@example.org
Technical availability % = (Annual transmission TWh + Technical capacity not used TWh) / The maximum technical capacity in TWh without losses.
Utilisation rate % = Annual transmission (TWh) / The maximum energy (TWh) that can be physically received through the HVDC link to the converter station excluding all HVDC link losses.