Owner-operator Eco Stor has connected what it claimed is the largest BESS in Germany to the grid, while its former majority owner is going to build a BESS in Finland.
The inauguration of the 103.5MW/238MWh battery energy storage system (BESS) project in Bollingstedt, Schleswig-Holstein, was announced yesterday (5 June) by the company on LinkedIn. It has been developed and deployed in partnership with developer EPW.
Eco Stor is a developer-operator that also has in-house engineering, procurement and construction (EPC) and system integration capabilities, with its Germany BESS projects designed with its own proprietary configuration. The firm originally also had its own BESS enclosure design, but now buys BESS from established providers.
Eco Stor launched construction on the Bollingstedt BESS a little over a year ago, and is also building an identically-sized project 5km away, called Schuby. It is also developing and building several much larger, 300MW/600MWh systems, part of its ‘Eco Power’ series.
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Eco Stor was acquired by investors X-ELIO, part of global infra investor Brookfield, and Natural Infrastructure Capital (NIC) last year from majority owner Å Energi, a Norway-based utility, as covered by Energy-Storage.news.
While it wasn’t clear at the time of the deal, it now has been confirmed it was an outright acquisition but only of the Germany segment of Eco Stor – Eco Stor GmbH – with Eco Stor AS (Norway) remaining a separate, Å Energi-owned firm still active in BESS, as evidenced by a concurrent announcement.
Eco Stor AS building in Finland
The day before Eco Stor GmbH’s announcement, Eco Stor AS announced it had entered into an agreement to develop and install a 50MW/50MWh BESS near Isokangas in central Finland, with some construction already underway.
Eco Stor AS will build and co-own the BESS along with Norwegian investment company Farvatn and Finnish energy storage company AmpTank. The consortium has reached final investment decision (FID) on the project which is set to come online in 2026.
The Isokangas project is located close to wind generation areas in central Finland and is located by a substation belonging to Finnish transmission system operator (TSO) Fingrid. The project has built-in optionality to expand from a 1-hour to a 2-hour system.
“BESS market is expanding, supported by high expected growth of onshore wind and solar power. Our objective is to utilize the Isokangas project as a stepping stone towards building more BESS projects in Finland,” says Dr. Trygve Burchardt, CEO of Eco Stor AS.
The announcement explained the Germany sale: “In 2024, Eco Stor divested its German first life grid BESS subsidiary, including a multi-GW pipeline of utility-scale BESS projects, to Brookfield-owned renewable energy developer-operator X-ELIO and private equity firm Nature Infrastructure Capital.”
Other shareholders alongside Å Energi in Eco Stor AS include Klaveness Marine and Farvatn Capital, the announcement added.
Amptank, co-investor in the Isokangas project, recently sold a 30MW/60MWh project to investor UB Renewable Energy Fund (AIF).
Germany headwinds and opportunities discussed at Energy Storage Summit Germany
The announcements come during a week when Solar Media hosted the inaugural Energy Storage Summit Germany, co-located with the Battery Show Europe 2025, in Stuttgart (3-5 June).
Big talking points at the event were regulatory challenges including the BKZ and the threat of grid fees returning for BESS in 2029, as well as what the potential introduction of a Capacity Market (CM) would mean for BESS (Premium access).
