Google has announced plans to develop a new data center complex south of Minneapolis that integrates wind, solar and what would become the world’s largest 100-hour iron-air battery system, supplied by Form Energy. The project aims to deliver multiday-duration energy storage to maintain continuous operations during severe weather or high demand, addressing renewable intermittency challenges. The iron-air batteries leverage a reversible rusting process to achieve storage at roughly one-tenth the cost of lithium-ion, enhancing grid reliability and supporting Google’s net-zero carbon objectives.