(Bloomberg) -- Uniper SE’s oil-fired power plant in Sweden suffered from a partial outage on Thursday morning, curbing stable power supplies at a time when they were needed the most. 

The boiler at one of the two units at the Karlshamn plant tripped, according to a filing with power exchange Nord Pool ASA. The facility, which has a total capacity of 670 megawatts and burns heavy fuel-oil, is operating again.  

“We had a short unplanned outage this morning, but the interruption was sorted quickly,” company spokesman Torbjorn Larsson said by email. “The unit is back online again today.”

German energy giant Uniper said on Tuesday that the plant had been operating “frequently from morning to night” over the past week to boost supplies in the south of Sweden. The firm is not obliged to disclose exactly which hours the plant is providing power to the market.

Also read: Sweden Turns to Burning Oil as Power Prices Soar to Record

Nuclear outages and a dearth of wind generation sent prices in that part of the country to a record earlier this week as Europe’s worst energy crisis in decades deepens. Power for Wednesday jumped to as high as 540.47 euros a megawatt-hour, before declining slightly for Thursday.

(Updates with unit’s return in the 2nd paragraph.)

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