Europe's Growing Investment in Long-Duration Energy Storage: Could Iron-Air Batteries Help Solve Multi-Day Renewable Gaps?

Europe is investing in technologies to help create a more reliable renewable energy system and one of the latest developments demonstrates the interest in long-duration energy storage.

Dutch start-up Ore Energy has signed a major agreement with energy supplier Budget Thuis to deploy up to 1 GWh of iron-air battery storage, with an initial phase of 400 MWh targeted for 2028. The company has also recently secured new Series A funding to accelerate commercial rollout and manufacturing.

Traditional lithium-ion batteries typically store energy for hours, but the iron-air battery will be designed to hold electricity for 24 to 100 hours. This makes them particularly interesting for balancing renewable generation over long periods of low wind or limited solar output.

Iron-air batteries are less energy efficient and bulkier than lithium-ion systems, but could be useful in grid-scale applications because they use relatively abundant materials such as iron, water and air. Lower material costs and a lesser reliance on critical minerals could also boost European supply chains.

As the renewable energy industry expands, it faces a major challenge: how to deal with times when clean electricity generation is too high, and then falls sharply due to changing weather. Long-duration storage could be an important part of addressing curtailment, while reducing reliance on fossil-fuel backup generation.

In terms of industry, generally this sort of development poses a few interesting questions:

Will long duration storage be a common feature of future renewable energy systems?
Can iron-air batteries and other technologies compete on cost with lithium-ion at utility scale?
How important is long duration storage relative to investments in grid modernization, interconnectors and demand-side flexibility?
Which sectors/areas will be the first to benefit from multi-day energy storage?

I’d be interested to see what others think about the role of long-duration energy storage in Europe’s energy transition. Do you see iron-air batteries as a major part of future grid infrastructure or do you think other storage technologies will have more of an impact?”

Source: Ore Energy announcement (August, 2026) via Electrek The above discussion is a summary of the reported developments and is intended to stimulate industry discussion, not to reproduce the original article.

https://electrek.co/2026/08/04/europe-is-betting-big-on-a-battery-that-runs-for-four-days/