US technology company Google plans to deploy large-scale iron-air battery storage from Form Energy as part of the power infrastructure for a new data centre in Minnesota, highlighting how hyperscale computing and AI workloads are reshaping energy strategies.
The project, being developed with utility company Xcel Energy, will include a 300 MW/30 GWh iron-air battery energy storage system, which Xcel says will be the largest battery by energy capacity ever constructed.
Designed to deliver electricity for up to 100 hours, the installation will store surplus renewable energy and discharge it during periods of high demand or low wind and solar output.
Data centres driving demand for long-duration storage
The battery system forms part of a broader clean-energy package supporting Google’s new data centre in Pine Island, Minnesota. Under the agreement, Xcel Energy plans to add 1.4 GW of wind and 200 MW of solar generation to the grid, together with the multi-day storage system.
The arrangement reflects growing pressure on utilities to supply large volumes of reliable low-carbon electricity as AI-driven data centre demand accelerates. Data centres underpin services such as search, cloud computing and AI workloads but require continuous power, making them challenging to run on intermittent renewable energy alone.
By pairing renewable generation with long-duration storage, the partners aim to smooth fluctuations in power output and maintain stable supply even during multi-day weather events that reduce renewable production.
Iron-air technology for multi-day storage
Form Energy’s system uses iron-air chemistry, which stores energy through a process sometimes described as reversible rusting. During discharge, iron oxidises when exposed to oxygen, releasing electrons; during charging, the rust is converted back to metallic iron.
The technology is less energy-dense than lithium-ion batteries but is designed for long-duration grid storage, where footprint is less critical and lower material costs can be advantageous.
Iron-air systems are typically capable of round-trip efficiencies lower than lithium-ion batteries but are intended to deliver much longer discharge durations at lower system cost, making them suitable for multi-day energy storage.
Scaling energy infrastructure for AI
For Google, the project also represents a new approach to procuring power for large facilities. Under the agreement with Xcel Energy, the company will fund the clean-energy infrastructure required for the site, with the aim of ensuring the additional demand does not raise electricity costs for other customers.
Industry analysts say such partnerships may become more common as hyperscale technology companies expand AI and cloud computing capacity. Global demand for electricity from data centres is expected to rise sharply over the next decade, creating new opportunities for long-duration storage technologies capable of supporting renewable-based power systems.
