Herrfors storage
Operating, 7 MW · 7.4 MWh, in Vöyri, owned by Oy Herrfors Ab. Every fact below is as a published source states it, with the address beside it; a field not shown is one no source gave, and nothing is guessed.
The battery
| Power | 7 MW |
| Capacity | 7.4 MWh |
| Duration | 1.1 hours |
| Status | Operating, as of 15 May 2026 |
| Municipality | Vöyri |
| Placed on the map | at the centre of Vöyri, its municipality (GeoNames) |
Who is behind it
| Owner | Oy Herrfors Ab |
| Built by | Merus Power (storage and services, per the release) |
| Business ID | 0180010-6 |
YTJ, by exact name: Oy Herrfors Ab. https://avoindata.prh.fi/opendata-ytj-api/v3/companies?businessId=0180010-6
Not published anywhere we have found: ultimate owner, developer, cells. The page says so rather than guessing.
What the sources say
Optimisation and trading contract for a 7 MW storage and a 5 MW electric boiler (2 May 2024). The release does not say where it is or whether it is running. CORRECTED 18 Oct 2026: was "unconfirmed" with no place. Herrfors (annual report news, 15 May 2026): its Ylivieska electric boilers take part in the reserve markets "yhdessä Oravaisissa sijaitsevan sähkövarastomme (BESS) kanssa", so the storage is at Oravainen, in Vöyri, and running. Merus Power's reference page gives a 7 MW / 7.4 MWh delivery at Oravainen working with an electric boiler, two containers, without naming the customer; the 7.4 MWh rests on that match. No start date is given by either.
Evidence and sources
- name: sttinfo.fi/tiedote/71040841/merus-power-toimittaa-oy-herrf…
- municipality: herrfors.fi/herrfors-konsernin-vuosikertomus-2025-on-julkai…
- capacity: meruspower.com/references/battery-energy-storage-system-co-ope…
From the owners’, developers’ and builders’ own releases, council decisions and permit bulletins, read by Vitreous and checked against the owners’ own words on 12 October 2026; a bracket such as “(Energy-Storage.news only)” in a field means the trade press is still the only source for it. Fingrid publishes no meter, no price and no instruction per battery, so this page carries no money: what one megawatt is paid in Fingrid’s markets is on the markets page, for the whole market and never for a named battery. List id FI-B062.