How a battery earns in Finland

Finland is a single bidding zone — FI — cleared each day on Nord Pool and balanced by the state TSO Fingrid. Wind already covers about 26% of national electricity (9,433 MW installed, now the second-largest source after nuclear) and forces curtailment on gusty days, while a connection queue of some 24,000 MW of new data-center load — roughly 5× Finland's nuclear fleet — keeps southern grid access tight through 2027. That swing is the battery's paycheck: over the last 30 days the day-ahead spread averaged €32/MWh, about 123% of the average price. There is no dedicated merchant-battery subsidy — Business Finland energy aid explicitly excludes storage built solely for the reserve market — but Fingrid prices storage lightly: only €0.90/MWh in and €0.60/MWh out, and its grid-storage capacity fee sits at half a power plant's. The earnings come from the market itself: day-ahead arbitrage stacked on FCR and aFRR reserves.

€32/MWh

Day-ahead spread — 123% of the average price (30 days)

26%

Wind's share of 2025 electricity — now Finland's 2nd source

24,000MW

Data-center load in Fingrid's connection queue — ~5× nuclear