A 100MW/200MWh BESS project in Estonia has been inaugurated by Baltic Storage Platform (BSP), a joint venture (JV) between Baltic developer Evecon, French independent power producer (IPP) Corsica Sole and investment manager Mirova.
The Hertz 1 battery energy storage system (BESS) will operate across a wide range of electricity and ancillary services markets, including frequency containment reserve (FCR), automatic and manual frequency restoration reserves (aFRR and mFRR), as well as intraday and day-ahead markets.
The Baltic region last year decoupled from the Russia-led BRELL network and synchronised its transmission network with continental Europe, increasing its need for fast-reacting ancillary service and system support assets. Perhaps related, ancillary service prices are currently ‘through the roof’, enabling internal rates of return (IRR) of 20-30% for first-movers, we heard at the Energy Storage Summit Central and Eastern Europe 2025 last year.
Hertz 1 is 25 km from the capital Tallinn and connects directly to the 330kV transmission network via an underground cable.
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BSP secured a ‘landmark’ financing package for the Hertz 1 and 2 projects in late 2025 from the European Bank for Reconstruction and Development (EBRD), the Nordic Investment Bank (NIB), and Edmond de Rothschild Asset Management.
The Minister of Energy and the Environment of the Republic of Estonia, Andres Sutt, said the project proves two things: “Firstly – private investors are capable and interested in backing large energy projects in Estonia. Secondly – the future is here. Ten years ago, this would have been the largest lithium-ion battery electric park in the world, thirty years ago, this would have been science fiction.”
Karl-Joonatan Kvell, CEO of Evecon, added: “Hertz 1 is a critical piece of infrastructure that allows us to manage our energy sovereignty with confidence while accelerating the transition to clean, renewable energy.”
The companies did not clarify which BESS supplier was used for the project, and site photos do not clearly reveal it either. The BESS is a containerised designer and made up 54 containers, indicating a capacity of around 4MWh each.
However, it did thank technology partners Yuso, Connecto, Energel and Nidec Conversion. Nidec Conversion is in the same group as Nidec ASI, a BESS system integrator which has a large market share in Europe.
The project eclipses a 53MWh project commissioned in early 2025 as the largest in Estonia. Construction on Hertz 2 in Aruküla is underway, for completion in late 2026.
