Why Iron-Air Batteries Could be a Manufacturing Game-Changer

A potential solution to the challenge of storing renewable energy is gaining commercial ground – and relies on the simple process of rusting iron.

For the manufacturing sector, which depends on consistent and affordable power, the development of iron-air battery technology presents a promising area of innovation.

Unlike conventional fossil fuels, renewable sources such as wind and solar have an intermittency problem, creating an energy supply gap when the sun is not shining or the wind is not blowing. The search for effective energy storage has long been dominated by lithium-ion technology.

However, a different chemical approach is now moving from the laboratory to the grid.

Mark Loveridge, Commercial Director of Renewable Exchange, explains: "After decades of dominance by lithium-ion, 2025 is potentially the turning point for long-duration energy storage (LDES) – and iron-air batteries are leading the charge."

The technology operates on the principle of reversible rusting. During the discharge phase, the battery takes in oxygen, converting iron into rust to release energy. To charge, an electrical current reverses the process, turning the rust back into iron and releasing oxygen.

Long-duration energy storage capabilities

The primary constraint of lithium-ion batteries in a grid context is their limited discharge duration, typically lasting two to four hours. This makes them less suitable for bridging longer gaps in renewable energy generation.

Iron-air technology is being developed to address this specific niche, providing a much longer storage cycle.

"They're capable of storing energy for 100+ hours – enabling wind and solar to keep the lights on, even when the sun doesn’t shine or the wind doesn’t blow," Mark explains.

This extended duration means iron-air systems could replace the fossil fuel peaker plants currently used to stabilise the grid during periods of high demand or low renewable output.

It makes them "ideal for grid-scale decarbonisation, especially during multi-day renewable lulls," adds Mark. 

From pilot projects to commercial-scale manufacturing

The technology has advanced from theoretical models to operational infrastructure, as highlighted by key developments in Europe and the US.

"This year, Ore Energy in the Netherlands delivered the world’s first grid-connected iron-air battery, and Form Energy in the US raised over US$400m to bring this tech to commercial scale," says Mark.

The Ore Energy pilot in Delft, connected in July 2025, serves as an important proof of concept, showing that these systems can be integrated into developed areas.

In parallel, Form Energy has established a commercial-scale factory in Weirton, West Virginia, on the site of a former steel mill. It is now producing batteries to fulfil orders from major utilities like Xcel Energy and Georgia Power, with the first projects expected to become operational in late 2025 and 2026.

Abundant materials

Beyond its technical performance, iron-air technology offers a distinct advantage in its material composition.

The global energy transition has raised concerns about shifting dependency from fossil fuels to rare earth minerals such as lithium, cobalt and nickel, which are geographically concentrated and have volatile supply chains.

Iron-air batteries are constructed from iron, water and air. The use of such abundant and inexpensive materials could lead to more stable and secure energy strategies for nations and industries, mitigating supply chain risks.

Furthermore, the active components are non-toxic and can be recycled at the end of the system’s operational life. While these batteries are heavy, bulky and have a lower efficiency compared to lithium-ion, these factors are less critical for large static installations, such as those next to a solar farm or manufacturing plant.

The main factor is the cost per kilowatt-hour, with iron-air technology targeting a price point below US$20/kWh, a fraction of the cost of current lithium-ion solutions.

This could allow utilities and large industrial users to store huge amounts of energy economically.