OSLO, July 2 (Reuters) - Sweden will have to import more electricity during winter as the country, a net power exporter to the rest of Europe, shifts from nuclear to wind, its grid operator said.
Last winter, the first since the closure of its Oskarshamn 1 reactor, stretched Sweden's resources as peak consumption rose by 800 megawatt (MW), triggering start-up procedures in its reserve energy plants.
Sweden's power balance will deteriorate further from next winter, the country will need imports and the situation will become worse with two more of its reactors closing by 2020, state-grid Svenska Kraftnat (SVK) said in a report on Monday.
"For next winter (if its a normal winter) we expect Sweden to (need to) import 400 MW more than it exports during the hour with the highest consumption," SVK's electricity system analyst Erik Hellstrom, and the author of the report, told Reuters.
Hellstrom said that if the coming winter is a 10-year winter (colder than a normal winter), Sweden's imports will rise by as much as 1,500 MW more than it exports in the hour with the highest consumption.
Of Sweden's eight remaining nuclear reactors, two will close soon, Ringhals 2 in 2019 and Ringhals 1 the year after, cutting a combined production of 1,700 MW from its power system, 40 percent of which is nuclear output-dependent.
"Wind power cannot contribute to the power balance during winter peak hours with the same availability as the nuclear power it replaces," SVK said.
The expansion of Sweden's wind power capacity, with new farms coming into the system, may also be insufficient to cover the deficit the lost nuclear reactors leaves, said SVK, warning low profitability may even prohibit planned power projects.
"The margins for the Swedish power balance and the ability to be self-sufficient with enough electricity under high-load situations are shrinking," said the report.
The highest electricity consumption Sweden recorded last winter was about 26,700 MW said the grid, nearly 40 percent of the whole Nordic region.
Sweden will need to add a further 2.6 gigawatt (GW) in power generation capacity by 2040 to avoid power shortages, SVK said last year, as the country will risk electricity shortfalls of 400 hours per year on average. (Editing by Alexander Smith)