Iron-air batteries show promising potential as a long-duration storage technology, which can further foster a zero-emission transition in steelmaking. The energy system, which contributes to more than 70% of global greenhouse gas (GHG) emissions, is the linchpin of global decarbonization efforts.
In contrast, the scaling of iron production necessary to meet the same deployed storage volumes with iron-air batteries is much more modest. Just one US DRI plant today can produce about two million tons per year, which if entirely used in iron-air batteries corresponds to 0.5 TWh of storage.
By continuing to optimise product design and smart capabilities, heat batteries will be critical to the UK’s transition to net zero. This technology can bring low-carbon heating to homes while helping ease pressure on the grid.
Iron-based flow batteries designed for large-scale energy storage have been around since the 1980s, and some are now commercially available. What makes this battery different is that it stores energy in a unique liquid chemical formula that combines charged iron with a neutral-pH phosphate-based liquid electrolyte, or energy carrier.
In an iron-air battery, an iron electrode is oxidized to iron hydroxide when the battery is discharged and reduced back to iron metal when the battery is charged. Meanwhile, the other electrode, an air electrode, absorbs oxygen from the atmosphere as the battery is discharged and releases oxygen as the battery is charged.
Storing energy as heat isn’t a new idea—steelmakers have been capturing waste heat and using it to reduce fuel demand for nearly 200 years. But a changing grid and advancing technology have ratcheted up interest in the field.