Google announced it will construct its first data center in Minnesota, located in Pine Island, approximately an hour southeast of Minneapolis. The facility will be supported by a 1.9 gigawatt clean energy initiative developed in partnership with Xcel Energy. This collaboration includes the deployment of a 300-megawatt iron-air battery system designed by startup Form Energy to ensure reliable power for the new center.
The comprehensive energy plan involves developing 1.4 gigawatts of wind power and 200 megawatts of solar capacity in collaboration with Xcel Energy. These generation sources will supply electricity to Form Energy’s battery, which is engineered to deliver its rated power for a continuous duration of 100 hours. With a total capacity of 30 gigawatt-hours, the system is slated to become the largest battery installation globally. This infrastructure is designed to extend the operational capability of the data center on clean energy sources, specifically addressing periods when renewable generation naturally fluctuates.
Long-duration energy storage is a critical component for stabilizing power grids that rely heavily on intermittent sources like wind and solar. These systems ensure that electricity remains available during the night or when weather conditions limit generation, a process grid operators refer to as “firming” the power supply. While grid-scale lithium-ion batteries currently serve this function, they are typically limited to shorter discharge periods compared to the proposed 100-hour capability of the Form Energy system. The partnership aims to demonstrate the viability of extended storage solutions for maintaining grid stability.
Form Energy differentiates its technology from the prevailing lithium-ion standard by utilizing an iron-air chemistry. Unlike batteries repurposed from the automotive sector, Form’s system generates electricity through the oxidation of iron pebbles. When oxygen from the surrounding air flows over the iron, the metal rusts, creating a flow of electrical current. The charging process reverses this reaction; electrical current deoxidizes the rust, returning the iron to its metallic state and releasing oxygen. This cycle allows for energy storage using abundant and low-cost iron rather than critical minerals.
The iron-air battery technology presents a distinct trade-off between efficiency and cost. These batteries are heavier and exhibit a round-trip efficiency of 50% to 70%, a figure significantly lower than the 90%+ efficiency typical of lithium-ion batteries. However, the primary advantage is economic viability. Form Energy projects that the cost of storage will reach $20 per kilowatt-hour, a price point at least three times lower than current lithium-ion alternatives. This cost reduction is essential for making long-duration storage economically feasible at the grid scale.
To facilitate the adoption of this emerging technology, the project introduces a new financial mechanism to Minnesota known as the “clean transition tariff” or “clean energy accelerator charge.” Google originally developed this framework in Nevada in collaboration with geothermal startup Fervo. Under this tariff structure, Google pays a premium to Xcel Energy, allowing the utility to invest in technologies that might be deemed too risky by regulators focused on minimizing costs for the general public. This arrangement protects regular ratepayers from shouldering the financial burden of experimental infrastructure.
The deployment of Form Energy’s technology in Minnesota is already underway through a separate initiative with cooperative utility Great River Energy. This installation will provide 150 megawatt-hours of storage for 100 hours, capable of delivering 1.5 megawatts of peak output to the grid. Form manufactures its battery systems at a facility in West Virginia and has successfully raised $1.4 billion in funding to date, according to PitchBook data, supporting its expansion into utility-scale projects.
