Waregem, Belgium, February 5th 2026 — Yuso, a leading battery energy storage system optimiser, announces the successful commencement of operations at the Hertz 1 BESS facility in Kiisa, Estonia. The 100MW/200MWh system was officially inaugurated on February 3rd, 2026. It will soon expand services to include ancillary market operations, marking a significant milestone for Baltic energy independence and grid stability.
The Hertz 1 facility is the largest battery energy storage system currently operating in the Baltic region. Co-owned by Mirova, Evecon, and Corsica Sole, the project demonstrates strong institutional confidence in the region's energy transition and the critical role of energy storage infrastructure.
"The Hertz 1&2 BESS come online at a pivotal moment for the Baltic energy system," said Michel Verschuere, Managing Director at Yuso. "As the region strengthens its energy independence following its joining the Continental Europe synchronous area, large-scale battery storage will play an essential role in maintaining grid stability and security of supply."
The facility will provide multiple critical grid services, including:
Frequency regulation to maintain grid stability
Automatic and manual frequency reserve response
Wholesale energy arbitrage to optimize market adequacy
Enhanced grid resilience for the Baltic power system
The timing of Hertz 1's operation is particularly significant as Estonia and its Baltic neighbors work to enhance grid independence and strengthen interconnections with the Continental European synchronous area. Battery energy storage systems like Hertz 1 provide the flexibility and rapid response capabilities essential for managing a modern, increasingly renewable-powered grid.
With ancillary service market operations set to begin in the coming weeks, the Hertz 1 facility will deliver its full range of capabilities to support Estonian and Baltic grid operators in maintaining reliable, affordable electricity supply.
About Yuso Yuso is an innovative energy platform providing one-stop-shop market-based energy solutions. The company offers access to wholesale markets for energy and flexibility through a fully digital and user-friendly platform with transparent pricing. Yuso provides both basic energy supply and injection products as well as advanced flex solutions including local and utility-scale battery energy storage systems. With required licenses as supplier, BRP, BSP, Scheduling Agent, Outage Planning Agent, and Voltage Service Provider, Yuso serves as a comprehensive route-to-market partner for battery energy storage projects across Europe. For more information, visit yuso.com.
About Mirova Mirova is a global asset management company dedicated to sustainable investment and an affiliate of Natixis Investment Managers. At the forefront of sustainable finance for over a decade, Mirova develops innovative investment solutions across all asset classes, aiming to combine long-term value creation with positive environmental and social impact. As a mission-driven company and certified B Corp, Mirova manages assets with the goal of steering the economy towards models that preserve and restore ecosystems and climate while supporting social inclusion, health, and well-being. For more information, visit mirova.com.
About Corsica Sole Corsica Sole is a French independent solar power producer and European leader in energy storage, with more than 150 MWp of solar capacity in operation and 360 MWh of storage. Founded in 2009, the company develops, finances, and operates solar, energy storage, and green hydrogen projects in France and across Europe, with a project portfolio exceeding 3 GW. Committed to a responsible approach, Corsica Sole rehabilitates brownfield sites and leverages its expertise to support electricity grid stability. For more information, visit corsicasole.com.
About Evecon Evecon is a renewable energy developer focused on wind, solar, and energy storage projects in Estonia, Latvia, and Lithuania. The company is committed to supporting the green transition in the Baltic region, working to increase renewable energy market share and ensure energy security. Evecon develops projects that contribute to clean energy production and grid stability, helping the Baltic states achieve their renewable energy goals. For more information, visit evecon.ee.
Media Contact:
Jean-François Steels
Head of Origination
jfsteels@yuso.com