Energy has announced the successful commission of the Rummu Battery Energy Storage System (BESS), a state-of-the-art 9 MW / 18 MWh storage facility co-located with the operational 20 MW PV plant. This integrated project marks a significant milestone in Enery’s strategic expansion in the Baltic energy markets, pairing renewable generation with advanced energy storage to unlock new dimensions of flexibility, reliability, and economic value.
The Rummu PV plant, located in Harju County, became operational in September 2023 and was one of Enery’s first utility-scale solar assets in Estonia. Recognizing the need for dynamic grid support and market optimization, Enery initiated the retrofitting of a co-located battery system, which came online in April 2025. Together, these assets form a hybrid system capable of delivering stable renewable power and participating in ancillary services’ markets.
Technical and Financial Innovation at the Core
Energy engineers the Rummu BESS with a configuration of 9 MW of power and 18 MWh of capacity to handle high-frequency charge and discharge cycles with seamless responsiveness.
Energy fully owns, operates, and optimizes the Rummu BESS as part of its integrated business model. Using an AI-based 24/7 cross-market optimization platform, Energy manages the asset by evaluating real-time and forecasted price signals and asset availability across multiple markets, enabling automated and revenue-maximizing dispatch decisions.
As Energy entered the BESS market ahead of many competitors, the financing of the Rummu asset represented a pioneering initiative. It was the first time Enery’s local financing partners engaged in supporting this type of infrastructure, making the endeavor both a learning and teaching experience. This collaboration laid the groundwork for battery storage to emerge as a bankable asset class in Estonia and potentially across the Baltics. Rummu BESS was financed by Swedbank, who recognized early on the strategic advantage of being a first mover in this evolving market. Their support was instrumental in contributing to the stabilization of the energy system through the deployment of cutting-edge energy solutions.
Technology as a Commercial Edge
“Rummu is not only a technical achievement but also a strategic cornerstone. It represents the convergence of digital intelligence, grid flexibility, and clean energy—all tailored to a region that’s fast becoming a key player in Europe’s renewable landscape.”
– Margus Potisepp, Head of Energy Estonia.
The cross-market optimization model behind Rummu’s strong performance isn’t limited to Energy-owned assets. It’s a key part of our Energy Portfolio Optimization services, which are also available to third parties with renewable and storage assets in Estonia. This approach is central to Energy’s broader offering for renewable and storage owners and industrial consumers seeking to improve the performance of their generation and storage assets and navigate today’s increasingly volatile and decentralized energy markets.
“This is particularly relevant for the Baltics, where high renewable penetration, market coupling, and price volatility make intelligent trading and flexible response a must-have, not a luxury.”
– Margus Potisepp, Head of Energy Estonia.
A Scalable Vision for the Region
The company sees the Baltics as a region with strong potential—not only due to its ambitious decarbonization goals but also its supportive regulatory environment. The Rummu BESS is a template for future projects in the Baltics and beyond, where co-location and digital integration will be key to extracting full value from clean energy infrastructure.
Looking ahead, Enery plans to continue deploying hybrid renewable-storage systems and building on the existing asset base across Central and Eastern Europe, with a strong focus on software-driven asset optimization, open digital platforms, and partnership-based scaling.
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