Following a summer of exceptionally low prices for spot market electricity, prices began to fluctuate wildly in September.
Over the summer, spot prices even dipped into negative territory. In July, the average untaxed price hit a record-low of just 1.7 cents per kilowatt hour (kWh), making it the cheapest in Europe for the first time.
But more recently, for example, spot prices on Tuesday shot up to more than 31 cents per kWh. Thursday's peak reached 30 cents per kWh at 8 pm.
The situation has puzzled some consumers, as continued warm weather hasn't prompted more electricity consumption, as is usually the case in autumn when cooler temperatures result in many households turning on electric heating systems.
The reason behind the price spikes is not increased consumption but fluctuations in supply and electricity transmission issues, according to Pekka Salomaa, the energy market chief at Finnish Energy, an industry interest group.
According to Salomaa, electricity prices in the summer were low due to an excess in supply. However the situation has changed and now domestic electricity production is lower and the output of wind turbines is comparatively lower than in August, for example.
Nuclear, transmission maintenance work
Another reason for the dip in Finland's electricity output is annual maintenance being carried out on its nuclear reactor in Loviisa. Its temporary shutdown prompted a 450 megawatt (MW) loss in output.
An energy market anomaly was seen on Thursday when electricity from Finland was transferred to Sweden, even though the market situation would have otherwise called for the opposite to occur.
On Wednesday, national grid operator Fingrid announced that the technical capacity to receive electricity from Sweden would be limited by maintenance work.
Fingrid said that electricity transmissions from Sweden to northern and southwestern Finland would be limited by around half of the levels under normal conditions. The grid operator said that the situation could lead to more price fluctuations than usual, and that the scenario would continue until mid-October, at the latest.
Both Fingrid and Finnish Energy confirmed that the transmission maintenance work has already affected electricity market prices.
"Domestic production is not enough in this situation. The situation would of course be different if Sweden's transmission connections were fully available," Salomaa explained.
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