Finland starts two backup power plants to prevent blackouts

HELSINKI, Sept 8 (Reuters) - Finnish power grid operator Fingrid started up two backup power plants on Thursday to balance the country's electricity system and prevent blackouts while repairs were made at a reactor seen as crucial to ensure reliable power supplies this winter.

Grid operator Fingrid also asked the electricity market for more short-term power, with extra supply coming at an "exceptionally high" price of 5,000 euros per megawatt hour (MWh), it said in a statement.

Regular wholesale power prices in Finland were at around 500 euros/MWh early on Thursday.

"The situation has been brought under control," Fingrid said in a statement.

Fingrid later said the two reserve power plants, Huutokoski and Forssa, were no longer needed and were shut down by 9 a.m. (0600 GMT).

Starting up the reserve oil-fired plants was triggered by an outage at Finland's new Olkiluoto 3 (OL3) reactor alongside a shortfall of wind power production, Fingrid told Reuters.

"OL3 was supposed to connect to the grid this morning with quite a generous capacity so seemingly the power markets had reacted to that and assumed it would be available but it wasn't," Fingrid control room manager Arto Pahkin said.

Fingrid warned in June it was concerned about its power supply this winter if OL3 could not reliably supply electricity.

OL3 operator TVO said it was repairing a safety valve at the reactor and the scheduled restart on Thursday morning had been postponed by a few hours.

"These kinds of things can happen while testing," a TVO spokesperson said.

Fingrid had been expecting OL3 alone would more than compensate for the loss of Russian power imports, stopped since May as Russian utility Inter RAO (IRAO.MM) had not received payments for power sold via pan-European exchange Nord Pool. read more

Reporting by Anna Kauranen and Essi Lehto, writing by Terje Solsvik and Gwladys Fouche; Editing by Anna Ringstrom and Edmund Blair

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