Google Commits to World's Largest Battery System in Minnesota, a 30 GWh Iron-Air Installation That Can Discharge for 100 Hours
A 300 MW Form Energy iron-air battery paired with 1.6 GW of wind and solar will power Google's new Pine Island data center, marking the largest energy storage project ever announced by capacity.
Overview
Google has announced plans to build a data center complex in Pine Island, Minnesota, powered by 1.9 gigawatts of new clean energy resources, including what will be the largest battery installation ever announced globally by energy capacity. The centerpiece is a 300-megawatt, 30-gigawatt-hour iron-air battery system built by Form Energy that can discharge continuously for up to 100 hours, according to TechCrunch. The project represents a significant bet on long-duration energy storage technology that has yet to operate at this scale.
What We Know
The battery is part of a broader clean energy package that includes 1,400 megawatts of wind generation and 200 megawatts of solar capacity, delivered through a partnership with Xcel Energy under a new tariff mechanism called the Clean Energy Accelerator Charge, as reported by Electrek. Google will cover all new grid infrastructure costs, and existing Xcel residential customers will not see higher electricity rates as a result, according to the agreement. Minnesota residential customers currently enjoy rates 27 percent below the national average.
Form Energy’s iron-air technology works through a process of controlled, reversible rusting. Cells filled with thousands of iron pellets are exposed to air, causing oxidation that releases electrons. The process is then reversed, returning the rust to metallic iron and storing energy in the process. The cells use a water-based, non-flammable electrolyte similar to what is found in standard alkaline batteries, as detailed by TechCrunch.
Form Energy CEO Mateo Jaramillo described the installation as “the largest announced energy storage project in the world,” according to Fortune. He also stated that the 100-hour discharge duration “is what’s required to provide true, firm capacity into the system.” The company expects to receive close to $1 billion for its contributions to the project, Fortune reported.
Manufacturing will take place at Form Factory 1 in Weirton, West Virginia, a former steel town. The facility is scaling toward an annual production capacity of 500 megawatts by the end of 2028, with battery deliveries to the Minnesota site expected to begin that same year. The broader deployment timeline spans from 2028 to 2031, as reported by Electrek. The project also benefits from Inflation Reduction Act domestic content bonuses.
Google separately committed $50 million to Xcel Energy’s Capacity*Connect program for grid reliability improvements, according to Google’s announcement. The agreement requires approval from the Minnesota Public Utilities Commission before electricity delivery begins.
What We Don’t Know
Several uncertainties surround the project. Form Energy’s iron-air technology has not yet operated at anything close to this scale. The company has smaller deployments planned in Minnesota, Colorado, California, Georgia, Virginia, New York, and Maine that will precede the Google installation, but none approach 30 gigawatt-hours. Whether the technology can maintain its performance characteristics at this capacity remains to be demonstrated.
The specific cost per kilowatt-hour for the system has not been disclosed publicly, though Form Energy has previously stated a target of $20 per kilowatt-hour of storage, which would represent roughly one-tenth the cost of lithium-ion systems. Whether that figure will hold at production scale is unknown.
Most existing battery storage installations are designed for four-to-eight-hour discharge cycles using lithium-ion chemistry, according to Fortune. Iron-air batteries are less energy-dense than their lithium-ion counterparts, making them better suited for large, stationary grid-scale applications rather than compact installations. The trade-off between energy density and duration is central to the technology’s value proposition, but long-duration storage at this scale remains commercially unproven.
Context
The announcement arrives as data center operators face mounting pressure to secure reliable clean energy. AI workloads are driving unprecedented electricity demand, and hyperscalers like Google, Microsoft, and Amazon have made aggressive carbon-free energy commitments that require solutions for periods when wind and solar generation falls short. A 100-hour battery can bridge multi-day weather events that would otherwise force reliance on fossil fuel backup generation.
The U.S. Energy Information Administration expects 24.3 gigawatts of new battery storage capacity to come online in 2026, surpassing the 15-gigawatt record set in 2025. However, virtually all of that capacity is lithium-ion with durations of four to eight hours. If Form Energy delivers on its timeline, the Google project would represent a qualitative shift in what grid-scale storage can provide, moving from peak-shaving and frequency regulation to multi-day firm capacity.
The project also carries industrial policy significance. Manufacturing at a former steel plant in West Virginia ties clean energy infrastructure to domestic production in a region historically dependent on heavy industry, a pattern the Inflation Reduction Act was designed to encourage.