I think this misses that that is ALL the nuclear station would lose by remaining online. A comparable coal/gas etc station would lose the same amount PLUS the cost of the fuel.
Also, a gas power station can be started right back up again within about 1h. It takes 12h to get a nuclear station back online (assuming no issues). So the moment they shut down they lose 12h+ of output.
(I cannot find the actual cost. In Denmark prices fell to -41.37E / MWh last week, and on that basis, a 1.6GW station (at max capacity) would lose 66k Euros / h. How much does it cost to just keep the place shut?)
The issue seems to be they can't shut down the hydro generation because of the flooding.
While what you say about "coal/gas etc" is true, it's easier to reduce nuclear power generation than to lower the water levels.
Also, https://en.wikipedia.org/wiki/Electricity_sector_in_Finland says coal+oil+gas make up only 5.5% of electricity production in Finland last year. Hydro is 16.3%, wind 14.1%, and nuclear 29.6%. Wind production also doesn't lose by staying online.
Also, a gas power station can be started right back up again within about 1h. It takes 12h to get a nuclear station back online (assuming no issues). So the moment they shut down they lose 12h+ of output.
(I cannot find the actual cost. In Denmark prices fell to -41.37E / MWh last week, and on that basis, a 1.6GW station (at max capacity) would lose 66k Euros / h. How much does it cost to just keep the place shut?)