Early on Sunday, the average price of electricity again fell into negative territory after substantial volatility in recent weeks. The cost of electricity was less than zero between midnight and 8am, meaning that Finland was generating considerably more electricity than it could use.
On Sunday afternoon, Finland was still exporting more than 1.1 gigawatts of electricity to Sweden and Estonia while consuming about 7.5 gigawatts.
Saturday's average price on the electricity exchange was less than one cent per kilowatt hour (kWh), after sinking to zero between 4 and 7 am.
Friday evening spike
That followed a sharp rise on Friday evening, the price briefly spiked to nearly 28 cents per kWh due to a drop-off in wind and solar power. Friday's daily average was just under 12 cents.
Earlier in the week, the price also fell below zero on Monday, Tuesday and Wednesday.
The sharp price fluctuations are mostly due to mild weather and variable electricity production from wind farms amid breezy conditions.
This weekend has been marked by warm weather with strong winds on the west coast and in western sea districts, as well as in northern Lapland. Unseasonably warm conditions are set to continue through most of Finland for the next few days, with highs in the low 20s in southern and central areas and in the mid-teens up north.
On Saturday, the mercury rose to a summery 23.9 degrees Celsius in Seinäjoki in western Finland and Pello in Finnish Lapland.
Coinciding hiccups
Adding to this past week’s fluctuations were several coinciding hiccups in electricity production: transmission of electricity between Finland and Sweden was limited due to fault repairs and maintenance work, the production of the old Olkiluoto 2 nuclear reactor in southwest Finland was suspended due to a rise in humidity detected in the turbine plant's generator, while Fortum's Loviisa nuclear power plant in the southeast is undergoing annual maintenance.
On Thursday, national electric grid operator Fingrid said that the outlook for this coming winter’s electricity supply looks good, without worries about shortages – which failed to materialise last winter either, despite production delays at the new Olkiluoto 3 nuclear reactor.