Almost half of Finland’s nuclear power will be out of action for more than a month in the fall

Loviisa nuclear power plant’s annual maintenance starts on Sunday. The two plant units of the power plant are maintained alternately, and the maintenance will continue until October 18.

The annual maintenance is longer than usual, because the second power plant unit is undergoing more extensive maintenance, which is carried out every eight years.

According to Fortum, Loviisa’s nuclear power plants produced a total of 7.9 terawatt hours of electricity last year, which is about 10 percent of Finland’s electricity production.

During the service, the serviced unit does not produce electricity. The electrical output of one plant unit is 507 megawatts in Loviisa.

Partly at the same time, the annual maintenance of Olkiluoto 3, owned by Teollisuuden voima or TVO, will be carried out, starting on September 10 and continuing until the last days of October.

The electrical power of Olkiluoto 3 is about 1600 megawatts. Simultaneous annual maintenance means that a total of more than 2,100 megawatts of Finland’s electricity production capacity is out of action for a good month.

The maximum production capacity of nuclear power in Finland is around 4,400 megawatts, which means that only slightly more than half of the production capacity of nuclear power plants is available during overlapping maintenance.

When looking at the entire electricity production, we are talking about a big chunk. For example, at nine o’clock on Thursday, the total demand for the whole of Finland was slightly less than 9,000 megawatts.

More variability

Annual maintenance can increase variability in the electricity market, estimates Energy Agency economist Jonata Heather.

“If a large pile of production drops out momentarily, for example periods without wind, the effect may be greater. The price of electricity may then rise higher than it would have risen without maintenance,” says Kanervo.

However, he emphasizes that in the fall electricity prices are typically moderate compared to the freezing winter months. In autumn, you don’t have to worry about running out of electricity.

Fingrid’s electricity market director Antti Keskinen is on the same lines. Annual maintenance can affect the price of electricity, but the price is also affected by many other factors, such as the weather.

“Simplifying a bit, we can say that the demand for electricity at this time of the year is around ten gigawatts (10,000 megawatts). If we take out the production of these nuclear power plants for a while, of course it can be reflected somewhat in the supply,” says Keskinen.

The combined production power of Olkiluoto 3 and one Loviisa plant unit is about 2100 megawatts.

Keskinen says that if there is a production shortfall, electricity can be imported from Sweden, for example.

No surprises

Loviisa power plant communications manager Mia Willberg says that the partial overlap of maintenance interruptions did not come as a surprise. Annual maintenance is planned for years ahead and notified to the electricity exchange in advance. The power plants are therefore aware of each other’s schedules.

“Traditionally in Olkiluoto, annual maintenance is scheduled for spring and in Loviisa for fall and summer as now”, says Willberg.

The maintenance of Loviisa power plant and Olkiluoto 1 and 2 is done annually. Willberg says that the maintenance rhythm of Olkiluoto 3 is different, however, which causes partial overlap.

“Olkiluoto 3 is serviced every six months. That’s why this year the maintenance is partly scheduled at the same time,” Willberg says.