RWE and Polarium with new storage project

23.04.2026

Source: E & M powernews

RWE and Polarium are joining forces to market flexibility on the German electricity market in a new way.

From the end of 2026, the energy group RWE intends to offer around 50 MW of capacity from the decentralized battery portfolio of Polarium, developer of battery storage systems and flexibility solutions, as part of its energy trading activities. More than 1,600 battery energy storage systems (BESS), distributed throughout Germany, will then be combined in a virtual battery via Polarium's cloud platform. This will enable their real-time control and market participation, while at the same time creating value from unused resources and grid infrastructure, according to a statement from the companies.

Ulf Kerstin, Chief Commercial Officer at RWE Supply & Trading, said: "Batteries are becoming increasingly important for a stable energy supply, and Polarium's virtual battery ideally strengthens our fast-growing portfolio of batteries and generation assets. By working together, we are bringing thousands of smaller storage units into the flexibility market, where they can help make the energy system more resilient, create additional value and keep the system in balance in real time."

Leif Ottoson, CEO of Polarium: "This agreement shows how decentralized battery systems, which are primarily used to secure infrastructure, can play an important role in the energy system. By aggregating thousands of batteries via our cloud platform, we can generate added value. We are supporting the integration of renewable energy and helping to stabilize the grid - while ensuring the availability our customers need. The partnership with RWE enables us to bring this flexibility to the market at scale."

Polarium is currently developing a portfolio of battery systems distributed throughout Germany, mainly for backup. Flexibility that is not needed for backup purposes will be combined virtually into a single market-ready resource. By the end of 2026, the virtual battery is to comprise at least 50 MW/135 MWh from more than 1,600 distributed systems.

This capacity is available to RWE under a multi-asset tolling agreement. Polarium provides access to aggregated flexibility for commercialization in all relevant flexibility markets, while RWE connects to the platform to utilize and optimize the combined capacity. Unlike traditional tolling structures, which typically comprise a single large storage facility, this approach bundles numerous distributed systems via the cloud, increasing flexibility and scalability.

Author: Günter Drewnitzky