Uniper Signs 5GWh Conditional Supply Agreement for CMBlu’s Organic Flow Batteries

Why It Matters

The partnership gives Uniper a long‑term, metal‑free storage solution, accelerating Europe’s transition to flexible, decarbonized power grids.

Key Takeaways

• Uniper commits to minimum 5 GWh of CMBlu flow batteries.
• Deliveries start 2027 in 100 MWh increments.
• Technology avoids lithium, cobalt, nickel, uses organic electrolytes.
• Contract runs through 2037, indicating long‑term partnership.
• Signals growing European interest in large‑scale flow storage.

Pulse Analysis

Uniper’s conditional supply agreement with CMBlu Energy underscores a strategic pivot toward organic solid‑flow batteries as a cornerstone of Europe’s energy storage mix. The 5 GWh commitment, spread over a decade‑long framework, provides the German utility with a scalable, non‑flammable solution that sidesteps the supply chain constraints of lithium‑ion chemistries. By leveraging organic redox‑flow chemistry paired with solid‑state components, CMBlu promises multi‑hour discharge capability, high cycle stability, and a lifespan measured in decades—attributes that align with grid‑balancing needs for renewable integration.

The deal arrives amid a broader resurgence of flow‑battery interest across the continent. Recent financing rounds for firms like VoltStorage and pilot projects from LEAG signal that investors and operators are re‑evaluating the economics of long‑duration storage beyond green‑hydrogen. Unlike hydrogen, flow batteries can dispatch power directly to the grid without conversion losses, while avoiding the critical‑material dependencies that have hampered lithium‑ion scaling. This convergence of technology maturity and policy support positions flow systems as a viable bridge between short‑duration batteries and emerging hydrogen ecosystems.

For Uniper, the agreement not only diversifies its storage portfolio but also strengthens its competitive edge in a market increasingly defined by flexibility and sustainability. CMBlu gains a high‑profile anchor customer, accelerating commercial rollout and validating its patented organic‑solid hybrid architecture. As European regulators tighten emissions targets and capacity markets reward fast‑response assets, the partnership could catalyze further deployments, prompting other utilities to explore similar contracts and potentially reshaping the continent’s long‑duration storage landscape.

Uniper signs 5GWh conditional supply agreement for CMBlu’s organic flow batteries

By Cameron Murray · February 3, 2026

German power firm Uniper has entered into a conditional supply contract with organic solid‑flow battery company CMBlu Energy for the delivery of at least 5 GWh of its technology.

The long‑term framework agreement runs until 2037 and gives Uniper the option to take delivery of battery systems from CMBlu in tranches of at least 100 MWh each, starting in 2027.

It follows a site‑acceptance test (SAT) of CMBlu’s battery system by Uniper. Both companies are headquartered in Germany.

CMBlu’s SolidFlow battery is based on the unique and patented combination of organic redox‑flow technology with solid‑state storage materials and is specifically designed for market‑driven use in the multi‑hour range, the company said.

It claims high cycle stability, a lifespan of several decades and non‑flammable electrolytes. It also benefits from the absence of critical raw materials such as lithium, cobalt, or nickel, as with most other non‑lithium‑based battery technologies.

Uniper first announced plans to pilot CMBlu’s tech at a project in Germany back in 2023. It has also tested other flow‑battery technologies, including that of Dutch firm Elestor (announced the previous year) in 2022, and has looked at the economic feasibility of large‑scale green‑hydrogen storage, winning a small EU grant for a project the same year.

Uniper is a spin‑out of the larger German‑headquartered utility and power firm E.ON.

While the firms didn’t specify which countries they were targeting for deployments, both are headquartered in Germany, so the first projects may well be there.

If so, that could represent a shift in appetite for the technology. In 2022, a flow‑battery executive speaking anonymously lamented that the country’s energy sector “did not think it needed flow batteries,” instead believing that a combination of lithium‑ion for short‑duration and green hydrogen for long‑duration would suffice.

Since then the green‑hydrogen sector has struggled to scale. In related developments, flow batteries appear to have become more viable for large‑scale projects: a flow‑battery firm VoltStorage raised a €30 million venture loan, a 10 MWh project has been completed, and power firm LEAG seriously considered building a 500 MWh project using iron‑flow batteries from ESS Inc.

As well as Europe, CMBlu is also active in the US market. We recently caught up with its North America president Giovanni Damato for an interview on ESN Premium.