Estonia Strengthens Energy Resilience: Hertz 1, One of Continental Europe’s Largest Battery Storage Parks, Opens in Kiisa
Press releases
KIISA, ESTONIA – February 3, 2026 – The Baltic Storage Platform (BSP) – a joint venture between Baltics leading renewable energy developer Evecon, French independent solar power producer Corsica Sole, and sustainable investment manager Mirova – today officially inaugurates the Hertz 1 battery energy storage system (BESS) in Kiisa.
The opening marks a historic milestone for the Baltic energy sector. Hertz 1, with its significant storage capacity of 200 MWh, is the first of two strategic projects (Hertz 1 and Hertz 2 are 100MW/200MWh each) designed to stabilize the regional power system following the Baltics’ synchronization with the European continental grid.
The project was made possible by a landmark €85.6 million financing package secured in late 2025 from the European Bank for Reconstruction and Development (EBRD), the Nordic Investment Bank (NIB), and Edmond de Rothschild Asset Management.
Hertz 1 Energy Storage Facility, Estonia
Hertz 1 Energy Storage Facility, Estonia
Hertz 1 Energy Storage Facility, Estonia
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Strategic Impact on National Security
The commissioning of Hertz 1 represents a major leap forward in Estonia’s energy independence and grid stability. By providing rapid-response frequency regulation services, the facility ensures that the electricity network remains resilient even during fluctuations in renewable energy production or unforeseen disruptions.
Flexible services for grid stability
The facility is designed to 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, enabling flexible and responsive support to the power system.
Through its participation in multiple electricity and ancillary services markets, Hertz 1 is designed as a flexible market-oriented asset, capable of responding to system needs in real time. This operational flexibility allows the project to support grid stability, market efficiency and the integration of renewable energy, while contributing to the overall reliability of the electricity market.
Reducing Price Volatility for Consumer
Beyond grid stability, large-scale battery storage also plays a growing role in mitigating electricity price volatility. By storing electricity when production costs are low and releasing it during periods of high demand, Hertz 1 contributes to easing extreme price fluctuations that consumers have increasingly experienced in recent years, while supporting a more efficient balance between electricity production and consumption.
Large-scale battery storage is also a key enabler for the integration of low-cost renewable energy into the electricity system. By capturing surplus renewable production when availability is high and prices are low, and making this energy available when demand increases, Hertz 1 helps maximize the value of renewable generation while supporting a more efficient and reliable power system.
Michael Coudyser, Chief Executive Officer of Corsica Sole, and Karl-Joonatan Kvell, Chief Executive Officer of Evecon
Visit of the Hertz 1 Energy Storage Facility, Estonia
Karl-Joonatan Kvell, Chief Executive Officer of Evecon
Awards ceremony
Anthony Bonello, Director of Operations and International Expansion
Matthias Lévy, Deputy Chief Executive Officer for Grid Access and Technical Director
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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.
From today, Estonia’s energy security is significantly stronger. With Hertz 1, our electricity system has gained resilience comparable to adding a major new power plant. 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.
Technological Innovation
Located just 25 km from Tallinn, Hertz 1 features a major technical first for Estonia: a high-voltage connection to the 330 kV transmission network via an underground cable. This development enhances the physical resilience of the connection and sets a new standard for integrating large-scale storage into the national grid.
The BESS facility is based on a containerized design, with 54 containers housing a total of 2,328 battery modules. Each container integrates battery racks along with cooling, fire protection, and monitoring systems, forming a safe and self-contained energy storage unit. This modular approach allows the system to store and deliver electricity efficiently while ensuring reliable operation throughout its lifetime.
The project would not have been possible without the strong support and close cooperation of the TSO, Elering. Their expertise, engagement, and collaboration have been instrumental in enabling the successful development and integration of the BESS facility and its long-term contribution to the power system.
Industrial Execution and Strategic Partnerships
The successful delivery of Hertz 1 also reflects the strength of the project’s industrial execution and close cooperation with key technology and engineering partners, including Yuso, Connecto, Energel, and Nidec Conversion. Through strong coordination across engineering, system integration and commissioning phases, the project was delivered within an ambitious timeline and in line with the highest technical and operational standards required for large-scale battery storage infrastructure.
Hertz 1 demonstrates Corsica Sole’s ability to deliver complex, large-scale battery storage solutions in highly demanding technical environments within an ambitious and tightly managed project timeline. By leveraging our international expertise in engineering, grid integration and battery system operations, we are proud to contribute to strengthening Estonia’s energy resilience and to support the Baltic region in its sustainable integration into the European electricity grid.
The lifespan of the BESS facility will be communicated transparently. As owner and operator, we will remain fully committed throughout its 15-year lifetime, ensuring that the system reliably delivers essential services to the grid over its entire operational life.
Partner Commentary
With the Baltics now synchronized to the European continental grid, storage is the critical link. Hertz 1 shows that grid‑scale storage is bankable at scale. As a partnership‑first investor, we mobilize long‑term capital with local developers and on‑the‑ground teams to deliver clean, reliable power and stronger energy security for the region.
As renewable energy production continues to grow rapidly across the European Union, energy storage has become a strategic challenge for ensuring energy independence and maintaining grid stability. Large-scale battery storage systems such as Hertz 1 are essential to balancing intermittent renewable generation with consumption needs, while supporting Europe’s transition toward a more resilient, low-carbon electricity system.
Looking Ahead
While Hertz 1 begins full operations today, the Baltic Storage Platform is already well into the construction of its sister project, Hertz 2 in Aruküla. Once both are completed by the end of 2026, the combined capacity will reach 200 MW / 400 MWh, forming one of the most powerful battery complexes in Continental Europe.
