OSLO (Reuters) - Another two-month delay at Finland's Olkiluoto 3 nuclear reactor, which was originally due to start operations in 2009, poses a risk to power supply this winter in the absence of Russian imports, grid operator Fingrid said on Thursday.
Test operations, suspended in April, will not restart until the end of July, operator Teollisuuden Voima (TVO) said late on Wednesday.
Regular power production at the new 1.6 gigawatt (GW) reactor, which will account for some 15% of Finland's electricity consumption when fully operational, will now start on Dec. 10 instead of Sept. 30 as previously announced.
"We were expecting this generation would even start this summer and now it's delay after delay, so of course the risk level has increased," Jukka Ruusunen, the head of power grid operator Fingrid, told Reuters.
Fingrid had been expecting that Olkiluoto 3 alone would more than compensate for the loss of Russian power imports this winter, he added.
Imports of Russian power stopped in May after Russian utility Inter RAO said it had not been paid for the power it sold via pan European exchange Nord Pool since May 6.
"Without Olkiluoto 3 the situation is quite tight because that would have been more than 10% of the peak demand alone," Ruusunen said.
Instead, Fingrid will need to lean more on imports from other Nordic countries, the growing domestic wind power fleet and a strategic reserve to meet peak demand in January and February, he added.
A last resort would be power rationing, Ruusunen said.
A tighter supply picture this winter would primarily lead to a price impact, with power becoming more expensive, said Marius Holm Rennesund at Oslo-based Thema Consulting.
"But I don't think there is any risk of rationing," he said.
Tor Reier Lilleholt, head of analysis at the Volue Insight energy data and research firm, said: "It is when it gets very cold and there is little wind you would have a challenge."
The reason for the fresh delay at Olkiluoto 3 were checks and repairs after the discovery of "foreign material" in the turbine's steam reheater, TVO said on Wednesday, without giving specifics on what the foreign material was.
Under construction since 2005, Olkiluoto 3 has faced several technical issues, sparking a legal battle between TVO and its partners, France's Areva and Germany's Siemens.
(Reporting by Nora Buli; Editing by Alison Williams)