Updated 5:15 PM
The sudden onset of winter chill, as well as a drop in nuclear power, led to a sudden spike in the price of electricity in Sweden.
Between Wednesday and Thursday the price per kilowatt hour on the Nordpool spot market went up by 500 percent. But it has now returned to normal levels.
The annual increase in demand caused by cold temperatures and Christmas lighting was made worse this year by several reactors being taken offline at the Ringhals and Oskarshamn nuclear power stations.