The Zero Fee Is the Receipt: Finland's Battery Case Moves From Reserves to Energy

For October and November 2026 Fingrid, Finland's transmission system operator (TSO), will charge a balance service volume fee of 0.00 euro per megawatt hour of production and consumption. In January 2025 the same fee stood at 1.73 euro. Fingrid's stated reasons are lower reserve costs and a better electricity trade result. Most of what Fingrid saves on reserves is what reserve sellers no longer earn, so the zero is in large part a receipt for the battery owner's lost revenue. The useful question is what replaces it.

The development

On 31 August Fingrid announced that balance responsible parties, the companies financially answerable for the gap between what their portfolios promised and delivered, will pay no volume fee for October. On 23 September it extended the zero to November. Both notices give the same two reasons: reserve costs below forecast and an electricity trade result above it. On 28 September Fingrid set its 2027 main grid fees 4 per cent higher, after an 8 per cent rise for 2026.

The tariff did not cut reserve revenue. Reserve prices fell and the tariff followed. Reserves are standby capacity the TSO pays for, sold on a ladder of speed. FCR-N, the frequency containment reserve for normal operation, corrects small everyday frequency swings. FCR-D, its disturbance sibling, acts when the frequency leaves the normal band, in separate up and down products. aFRR, the automatic frequency restoration reserve, pulls the frequency back within minutes. mFRR, the manual frequency restoration reserve, is the slowest rung. Each pays a capacity price, in euro per megawatt per hour, for being available.

We took Fingrid's open hourly price data for all seven capacity products and averaged January to September of each year. Every product fell, by 57 to 88 per cent against 2025 and by 79 to 88 per cent against 2024. FCR-N, the highest priced of the seven in 2024, averaged 50.08 euro then, 21.44 euro in 2025 and 9.15 euro in 2026. The simple averages are ours.

Average capacity price by product in Fingrid's hourly markets, January to September of 2024, 2025 and 2026, in euro per MW per hour. All seven products fell in 2026, by 57 to 88 per cent against the same months of 2025. Simple averages of hourly prices, not weighted by volume. Source: Fingrid open data, datasets 317, 318, 283, 52, 51, 329 and 330; averages are our arithmetic.

What it actually means

Our read of the cause is supply, not policy. Fingrid does not publish which technologies clear its auctions, so the link is an inference. Fingrid's open data on installed battery storage shows the fleet growing from 1,215 MW on 11 March 2026 to 2,013 MW by the end of September. Fingrid's non-binding procurement forecast for 2026 adds up to about 1,700 MW across every reserve product and both directions together. The comparison is crude, nameplate against directional megawatts, but the fleet has outgrown the reserve markets.

Now the other leg. The day-ahead market is the auction that sets tomorrow's power price for every delivery period. A battery earns the spread: it buys the cheapest hours and sells the dearest. We measured the Finnish spread the way a two-hour battery meets it, the mean of the two highest hours of each day minus the mean of the two lowest, using Nord Pool prices as published by Elering. It averaged 72 euro per megawatt hour in January to September 2024, 83 euro in 2025 and 68 euro in 2026. That is a stable range, not a collapse. The composition did change: negative-price hours in those months fell from 550 in 2024 to 52 in 2026 on the same series, a first sign of the fleet lifting the floor.

Put the two legs on one scale. A megawatt selling FCR-N every hour of a year at the January to September average price would have earned about 439,000 euro at 2024 prices and about 80,000 euro at 2026 prices. A one megawatt, two-hour battery cycling once a day at the day-ahead spread, with perfect foresight and before losses, would have earned about 53,000 euro and 50,000 euro. Both are illustrative ceilings, not forecasts. They are not alternatives either: a real asset stacks slices of both. Added together they fell from roughly 490,000 to 130,000 euro. Energy did not replace the reserve revenue. It became the larger share of a smaller total: day-ahead was worth 12 per cent of the FCR-N line in 2024 and 62 per cent in 2026.

Illustrative annualised value per MW at January to September average prices. FCR-N held every hour falls from about 439,000 euro to 80,000 euro between 2024 and 2026. One daily cycle of a two-hour battery on the day-ahead spread stays near 50,000 to 60,000 euro. Added together the two fall from roughly 490,000 to 130,000 euro. Both are ceilings with perfect foresight, before losses, fees, availability and degradation. Source: Fingrid open data, dataset 317; Nord Pool day-ahead prices via Elering; annualisation is our arithmetic.

Our read is that energy carries more of the stack each year from here, for three reasons. First, depth. The day-ahead market prices the whole Finnish system, while the entire reserve forecast is about 1,700 MW. Second, granularity. Day-ahead has cleared in 15-minute periods since delivery day 1 October 2025, which gives a fast asset more edges to trade. Third, the real-time premium. Intraday trading, the market that runs after day-ahead closes, trades on our read toward the imbalance price, the price at which deviations are settled every quarter hour. On Fingrid's imbalance price data, the daily gap between the dearest two hours and the cheapest two hours of quarter-hour prices averaged 159 euro per megawatt hour in April to September 2026, against 67 euro day-ahead on the same quarter-hour measure. That spread is a reference, not a venue: a battery reaches it through intraday trades and balancing energy bids, with forecast error in between.

The caveat sits in the same series. That real-time gap averaged 471 euro in April to September 2025, so it has fallen by two thirds as the fleet grew. Energy markets are deeper than reserve markets, not immune to batteries.

The daily two-hour spread in Finland, April to September of 2025 and 2026, day-ahead against real time. The real-time spread on Fingrid's imbalance price fell from 471 to 159 euro per MWh and still stood at about 2.4 times the day-ahead spread. The 2026 bars are both measured on quarter-hour prices; the 2025 day-ahead bar uses hourly prices, the only resolution that market had then. Source: Nord Pool day-ahead prices via Elering; Fingrid open data, dataset 319; spreads are our arithmetic.

What gets better from here

The data and Fingrid's own plans give three reasons for confidence. First, the highest priced reserve product looks to have found a floor. The monthly FCR-N average bottomed at 5.43 euro in December 2025 and has held between 6.69 and 11.62 euro in every month of 2026 so far, while the fleet grew by about 800 MW from March. September was the highest month since October 2025. Not every product has turned: aFRR down was still falling in September. Second, the day-ahead spread averaged 91 euro in September, the second highest month of 2026, against 99 euro in September 2025. Third, demand is coming. Fingrid says new consumption of over 8,000 MW is connecting under agreements already concluded, with no date attached. Our read is that more load against weather-driven supply widens spreads, provided the new load is not flexible enough to buy the same cheap hours a battery wants. On that read most of the repricing is behind Finnish batteries and the upside sits with demand growth.

Monthly average FCR-N hourly market price in Finland, January 2024 to September 2026, in euro per MW per hour. The price fell through 2025 to a low of 5.43 euro in December and has held between 6.69 and 11.62 euro in every month of 2026 while the installed battery fleet grew from 1,215 MW in March to 2,013 MW in September. Simple monthly averages of hourly prices. Source: Fingrid open data, datasets 317 and 424; averages are our arithmetic.

Who is affected and how differently

Owners of batteries built on a reserve case have already taken the hit. Their upside now depends on trading capability.

Developers still have a case. For 2027 the tariff side barely moves: Fingrid's 2027 price list sets the storage capacity fee at 98.54 euro per MW per month in each direction with energy fees of 0.74 and 1.11 euro per megawatt hour. For a main grid battery cycling daily that is about 3,800 euro per megawatt a year, a small charge. The 2029 structure Fingrid intends to decide by year end is a different matter.

Investors and lenders should date-stamp every reserve assumption. A model calibrated on 2024 or 2025 capacity prices is arguing with the TSO's own data.

What to do about it

Rebuild the stack with energy as the base case and reserves as the upside, on 2026 hourly prices.
Compare one-hour and two-hour builds on spread capture, not reserve availability.
Score the optimiser as carefully as the hardware. Energy value is earned by forecasting and execution.
Stress the energy leg: run a case in which the real-time premium keeps narrowing.

What Fingrid's 77 percent fee cut actually tells Finnish battery owners, our August piece.
The hedge sits out 2027, on the end of the fixed yearly FCR price.

Where the case stands now

This is the kind of question we at Auranova Ventures work through with developers and investors across the Nordics, Baltics and wider Europe. The prices, fees and fleet figures above are Fingrid's and Nord Pool's. The averages, the annualisations and the read that energy carries the Finnish stack from here are ours. When we model a Finnish battery today we start from the spread and add reserves as an option. If you hold a Finnish model built the old way round, reply and we will show you how we would re-cut it.

What share of your Finnish revenue case comes from energy today and what share will it need to be in 2028?

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