Emaldo Market Review September: The Finnish Ancillary Services Market

Issue 4 | October 2026, covering September 2026

Where we are now

In last month’s review we said we would look at whether the autumn demand season was delivering the revenue improvement that the seasonal pattern suggests. September brought stronger energy trading conditions, driven largely by a temporary nuclear outage, but the reserve capacity markets that matter most for residential batteries stayed low. This is why Grid Rewards payouts have not increased.

September in the numbers

According to Clean Horizon, Finnish battery revenues in September recovered to levels last seen at the beginning of the year. The 1-hour day-ahead spread rose by 68%, partly reflecting the impact of the scheduled outage of Olkiluoto 3 from September 10 onward. This followed August, when the daily day-ahead spread averaged 65 €/MWh, tripling compared to the previous month, with volatility on the aFRR and mFRR energy markets following the same trend.

The improvement came almost entirely from energy trading rather than reserve capacity payments. It was also helped by one of Finland’s largest power plants being offline for planned maintenance, which is a temporary effect.

Why this has not changed Grid Rewards

Reserve capacity prices remain low. Fingrid itself announced that it will not invoice the volume fee for production and consumption in October 2026, because of lower power system reserve costs and a higher electricity trade result. Lower reserve costs for the grid mean lower reserve payments for batteries.

Battery supply also continues to grow quickly. Clean Horizon reports that Finland’s operational battery capacity went from 295 MW to 1,614 MW between September 2025 and September 2026. That compares with Fingrid’s 2026 obligations of 126 MW for FCR-N and at most 305 MW for FCR-D up.

As a result, trading now matters more than reserves. Clean Horizon found that in Finland the 4-hour index fell to 152 k€/MW annualised in 2026, with day-ahead trading bringing in more than ancillary services, at 76 k€/MW against 60 k€/MW. Residential batteries rely more on reserve capacity markets than on large-scale energy trading, so a month of wider day-ahead spreads does not translate into higher payouts.

What is coming next

Fingrid is changing how it buys reserves. It has decided not to acquire frequency containment reserves from the yearly market for 2027, so domestic FCR procurement will only be carried out on the hourly market. Fingrid says this will significantly increase the volume of FCR hourly market procurement. Battery owners will compete for that volume on a daily basis.

The Nordic connection to MARI, the European mFRR platform, has moved later. The Nordic TSOs have postponed their joint connection, and September to October 2027 is now considered the most likely date. As we reported last month, independent aggregation in the mFRR market also remains on hold while Fingrid works through the legislative changes required.

Over the longer term, demand for flexibility is set to grow. Finland received about 68 GW of consumption connection requests in a single year, according to Fingrid’s half-year report for January to June 2026. New consumption from data centres, electrification and industry should create more need for batteries that can balance the grid.

What this means for your earnings

Grid Rewards payouts in Finland have not increased. September’s stronger trading conditions were driven by wider day-ahead spreads during a temporary nuclear outage, while reserve capacity prices remained low and battery supply continued to grow.

The structural drivers are positive: rising electricity demand, more FCR volume moving to the hourly market from 2027, and the eventual MARI connection. Emaldo will keep working with our Finnish partners to access the widest possible range of markets, evolve as the market changes, and grow what your battery earns. Your battery also continues to save you money on your electricity bills every day, regardless of reserve market prices.

Next month

In our next review we will cover price movements across FCR, aFRR, mFRR and the intraday market in Finland for October, including the effect of Olkiluoto 3’s return from maintenance