Main grid transmission reliability rate reached the highest recorded level in 2023

The main grid transmission reliability rate indicates the amount of energy transmitted for consumption in the main grid in relation to the total energy available for transmission. Last year, the transmission reliability rate was the highest since measurements began at 99.99995%. Several other key figures describing the main grid also reached record highs. The frequency quality in the Nordic synchronous area remained good.

Key figures for the main grid in 2023: ( The averages for the preceding five years are given in parentheses.)

• The transmission reliability rate in the main grid reached a record-setting 99.99995% (99.99989%). 
• The volume of electrical energy not transmitted for consumption because of disturbances in Fingrid’s network was smaller than ever before at 33 MWh (75 MWh).
• The number of electricity supply interruptions (≥ 30 seconds) caused by disturbances was just 0.05 per connection point (0.14). Disturbances caused an average of 0.82 minutes (4.5 minutes) of interruptions at connection points.
• The volume of energy that was not received by the main grid from power plants was 11 MWh – the lowest ever level – and the imputed detriment to electricity producers was EUR 1,000.
• The system minute was 0.15 min (0.41 min), the lowest recorded level. One system minute corresponds to the interruption of all transmission for one minute compared to the annual peak demand of the system.
• The average interruption time was the lowest ever at 0.24 min (0.46 min). The Average Interruption Time (AIT) is calculated by dividing the untransmitted electrical energy (MWh) by the average annual transmitted energy (MWh)
• The imputed economic detriment that disturbance interruptions caused to consumer customers was EUR 3.6 (4.5) million. This is the third-lowest value on record.

The quality of frequency in the Nordic synchronous area was good. In 2023, the frequency was outside the normal range (49.9–50.1 Hz) for approximately 9,600 minutes. The frequency quality metric was also below 10,000 minutes last year. The upper limit set in the European network code is 15,000 minutes, and the Nordic target is 10,000 minutes.

Further information is available on our website under Electricity transmission reliability rate. The website also provides annual fault statistics for the Nordic and Baltic AC network and fault and availability information for the cross-border connections.

Further information:

Markku Piironen, Specialist, Fingrid Oyj, tel. +358 30 395 4172
Email addresses firstname.lastname@fingrid.fi