Centrica Energy has agreed to toll a 125 MW battery under construction in eastern Finland. It agreed to toll an almost identical one four weeks earlier. Both contracts are partial, both were signed with the same developer, and neither discloses a price, a term or how much of the asset is actually covered. Together they are the entire Finnish battery offtake market in Enerdatics' records.
Key takeaways
- COVENERGO and Delta Capacity have signed a tolling agreement with Centrica Energy for the Akku One battery storage project in Finland, announced on 5 October 2026. Centrica Energy will also provide route-to-market, ancillary services and battery optimisation services.
- Akku One is a 125 MW/300 MWh standalone battery at Lapinlahti, Finland, which began construction on 22 September 2026. COVENERGO holds a majority interest and Delta Capacity is the EPCM contractor, responsible for securing offtake, construction and long-term asset management.
- The agreement is a partial tolling agreement, combining contracted revenue certainty with retained exposure to merchant market upside. Enerdatics records the capacity offtaken as 125 MW, which is the project's full power rating, while the share of the asset actually tolled is not disclosed. Neither the tariff nor the duration is disclosed.
- It is Centrica Energy's second partial toll of the month, following an agreement for the 125 MW/300 MWh Karppio battery at Teuva on 10 September 2026. Both assets were bought ready-to-build from Vinci's Helios Nordic Energy, and Delta Capacity appears in both ownership groups.
- Enerdatics records 48 European battery offtake contracts. Exactly one discloses a tariff, a 17-year resource adequacy agreement for the 48 MW Konin project in Poland at $63.41 per MWh. Twenty-one of the 48, including both Finnish contracts, disclose no duration.
What does a battery toll actually transfer?
The right to decide when the battery runs. Under a tolling agreement the offtaker pays the owner a fixed sum and in return gains the right to charge and discharge an asset it does not own. The owner receives contracted revenue and gives up market exposure. The offtaker takes the trading upside and the volatility, and does the work of bidding the asset into wholesale, balancing and ancillary markets.
A partial toll splits that. Part of the asset is contracted and the rest stays merchant, so the owner keeps some of the upside and some of the risk. For Karppio the record is explicit that revenue certainty applies to part of the asset while merchant exposure and upside are preserved on the untolled capacity. For Akku One it says the same thing in summary. What neither says is where the line sits, and that is the figure a reader would need to value either contract.
Why does the 125 MW in the record not mean 125 MW is contracted?
Because the field records the project, not the contracted share. Enerdatics lists the capacity offtaken for Akku One as 125 MW, which is exactly its nameplate rating. The agreement is described as partial. Both statements cannot be read literally at the same time, and the resolution is that the capacity figure identifies the asset under contract rather than the volume of it that Centrica has committed to pay for. The Karppio record, by contrast, leaves the field empty.
This matters because a tolled megawatt and a merchant megawatt are worth different amounts and carry different risk. A reader who treats the 125 MW as contracted capacity is valuing a fully contracted battery. A reader who notes the word partial is valuing something between a fully contracted asset and a merchant one, with no way to say where. On the figures published, the second reader is right and still cannot finish the calculation.
Why is one offtaker signing the same contract twice?
Because the assets are nearly the same and so is the counterparty on the other side. Karppio and Akku One are both rated 125 MW with 300 MWh of energy, giving a duration of 2.4 hours. Both were acquired ready-to-build from Helios Nordic Energy, a Vinci subsidiary, and Delta Capacity sits in both ownership groups, paired with the Strioga Family Foundation at Karppio and with COVENERGO at Akku One. Enerdatics has already shown that these two projects were sold to a repeated specification by the same seller, and the offtake has now repeated as well.
For Centrica the relationship predates both. It signed an optimisation agreement for Delta Capacity and WOOD and Company's Ange battery in Sweden in April 2026, and it holds a toll on Zelestra's 99 MW Hilgermissen battery in Germany. Commercial familiarity with an operator is worth a great deal to a toller, because the toller carries the consequences of the asset's availability and response. Elsewhere in Europe that familiarity has run further still, with one utility buying a battery outright from a developer it had already been tolling.
Enerdatics records 48 European battery offtake contracts, and exactly one of them discloses a tariff: Econergy's 17-year resource adequacy agreement for the 48 MW Konin project in Poland, at $63.41 per MWh. Twenty-seven of the 48 state a duration, which leaves 21 that do not, and both Finnish contracts are in that group. Finland accounts for two of the 48 in total, both signed by Centrica Energy, both partial, both on 125 MW/300 MWh assets from the same seller, four weeks apart.
What does the deal signal for Finnish storage?
It signals that Finland's battery revenue market is being built by one buyer at a time. A country with 28 recorded battery transactions since the start of 2024 has two recorded offtake contracts, and the same company is on the buying side of both. That is not a market with a price curve. It is a market in which the first mover sets the structure, and the structure being set is the partial toll rather than the full one.
That choice is informative. A full toll would suit an owner who needs certainty to raise debt. A partial toll suits an owner who believes Nordic volatility is worth keeping some exposure to, which is a reasonable view in a wind-heavy system with wide intraday spreads. Expect Finnish batteries reaching construction to be marketed on that basis, with a contracted layer sized to satisfy lenders and the rest left open. The number to watch for is the one neither of these contracts gives, which is how large the contracted layer has to be before a Finnish battery can be financed.
Frequently asked questions
What is a partial tolling agreement for a battery?A tolling agreement gives the offtaker the right to charge and discharge a battery it does not own in exchange for fixed payments to the owner. In a partial toll only some of the asset is contracted, so the owner keeps merchant exposure and upside on the rest.
How much of the Akku One battery is tolled to Centrica Energy?Not disclosed. Enerdatics records the capacity offtaken as 125 MW, which is the project's full power rating, while the agreement itself is described as partial, so the contracted share cannot be derived from the published figures. The tariff and duration are also undisclosed.
What is the Akku One battery project?A 125 MW/300 MWh standalone battery at Lapinlahti in Finland, giving a duration of 2.4 hours. Construction began on 22 September 2026. COVENERGO is the majority owner and Delta Capacity is the EPCM contractor, after the pair acquired the project ready-to-build from Vinci's Helios Nordic Energy.
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