Evecon, Mirova and Corsica Sole Inaugurate First of Two 100MW/200MWh BESS in Estonia

Why It Matters

The project proves that private capital can quickly mobilise large‑scale storage to stabilise the newly integrated Baltic grid and accelerate the region’s renewable transition.

Key Takeaways

• 100 MW/200 MWh BESS inaugurated in Estonia.
• Supports FCR, aFRR, mFRR, intraday, day‑ahead markets.
• Ancillary service prices enable 20‑30% IRR for early projects.
• Funded by EBRD, NIB, Edmond de Rothschild.
• Hertz 2 expected 2026, expanding Baltic storage capacity.

Pulse Analysis

The Baltic states’ 2025 break‑away from the Russia‑led BRELL network and their subsequent synchronization with the European grid created a sudden demand for fast‑acting balancing resources. Frequency‑containment and restoration reserves, once supplied by conventional generators, now require sub‑second response times that only battery storage can reliably provide. As a result, ancillary‑service markets have surged, delivering premium prices that make high‑capacity BESS projects financially attractive and strategically essential for grid reliability.

Hertz 1’s launch underscores a broader shift toward private‑sector financing of energy infrastructure in the region. Backed by the European Bank for Reconstruction and Development, the Nordic Investment Bank and Edmond de Rothschild, the venture secured a financing package that reflects confidence in the projected 20‑30% internal rates of return. This level of return, driven by soaring reserve prices, signals to investors that large‑scale storage is no longer a niche asset but a core component of the Baltic power market’s economics, encouraging further capital inflows and competitive development.

Technologically, the Hertz 1 installation uses a containerised architecture—54 modules each roughly 4 MWh—integrating expertise from Yuso, Connecto, Energel and Nidec Conversion. This modular approach shortens construction timelines and simplifies scaling, paving the way for the upcoming Hertz 2 project slated for late‑2026. Together, the two 100 MW facilities will more than double Estonia’s battery capacity, bolstering energy sovereignty, smoothing renewable intermittency, and positioning the country as a testbed for next‑generation grid‑balancing solutions in Central and Eastern Europe.

Evecon, Mirova and Corsica Sole inaugurate first of two 100MW/200MWh BESS in Estonia

By Cameron Murray · February 4 2026

A 100 MW/200 MWh battery energy storage system (BESS) project in Estonia has been inaugurated by Baltic Storage Platform (BSP), a joint‑venture between Baltic developer Evecon, French independent power producer Corsica Sole, and investment manager Mirova.

The Hertz 1 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 system with continental Europe, increasing its need for fast‑reacting ancillary‑service and system‑support assets. Ancillary‑service prices are currently “through the roof”, enabling internal rates of return of 20‑30 % for first‑movers, as noted at the Energy Storage Summit Central and Eastern Europe 2025.

Hertz 1 is located 25 km from the capital Tallinn and connects directly to the 330 kV transmission network via an underground cable.

“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.”

— Andres Sutt, Minister of Energy and the Environment of the Republic of Estonia

“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.”

— Karl‑Joonatan Kvell, CEO of Evecon

BSP secured a “landmark” financing package for the Hertz 1 and Hertz 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 companies did not specify which BESS supplier was used for the project, and site photos do not clearly reveal it. The BESS is a containerised design made up of 54 containers, indicating a capacity of around 4 MWh each. Technology partners thanked include Yuso, Connecto, Energel, and Nidec Conversion (part of the Nidec ASI group, a major BESS system integrator in Europe).

The project eclipses a 53 MWh installation commissioned in early 2025 as the largest in Estonia. Construction on Hertz 2 in Aruküla is underway, with completion expected in late 2026.

Image caption: A birds‑eye view of the Hertz 1 project. (Image: BSP / Karli Saul)