The average price furthermore represents an increase of 0.30 kronor over the past month as temperatures have plunged and demand soared accordingly.
The spot price, which peaked at 1.30 kronor per kWh in Lucia this weekend, is used as the basis for the calculation of variable electricity prices for households and businesses.
The average price for the whole of 2010 - 0.55 cents per kWh, is a full 40 percent above the average price recorded in 2009, according to the firm's figures.
The development of the futures market, which provides the basis for calculating fixed prices for electricity, has meant that it has become extremely expensive for consumers to fix prices, the firm's CEO John Öhnell argued in a statement.
Poorly refilled reservoirs, continuing problems with nuclear power generation and an average temperature which is seven degrees below normal, have placed upward pressure on electricity prices.
"The market is afraid of the weakness of hydrology and that the cold weather does not ease," Öhnell said.
Öhnell expects price pressures to wane in 2011, perhaps as early as January:
"Our assessment is that the price will be about 0.10 kronor lower than in December if the weather returns to normal temperatures," he said.