Google to Build World's Largest Battery System in Minnesota

100-hour iron-air battery system to power new data center complex

Published on Feb. 28, 2026

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Google announced plans to develop a new data center complex south of Minneapolis that will be powered by a massive renewable energy system, including the world's largest battery storage system capable of providing up to 100 hours of power. The battery technology, developed by startup Form Energy, uses iron-air chemistry to offer multiday durations of electricity storage, unlike typical lithium-ion batteries that max out at 4-8 hours.

Why it matters

This project represents a major milestone for the long-duration battery storage industry, which is critical for enabling renewable energy to fully replace fossil fuel-based baseload power. The ability to store renewable energy for extended periods helps address the reliability concerns that have historically hindered wider adoption of wind and solar power.

The details

The Google-Xcel Energy partnership for the Minnesota data center project includes building 1.4 gigawatts of wind power, 200 megawatts of solar, and a 300-megawatt Form Energy battery system. Form's iron-air battery technology functions through a reversible rusting process, allowing the batteries to operate at about one-tenth the cost of lithium-ion and provide power for up to 100 hours at a time.

  • Google announced the project this week.
  • The 300-megawatt Form Energy battery system is scheduled for installation in 2028.

The players

Form Energy

A startup developing long-duration iron-air battery technology that can provide up to 100 hours of electricity storage.

Mateo Jaramillo

Co-founder and CEO of Form Energy, a former Tesla executive who left to focus on frontier energy storage technologies.

Xcel Energy

A Minnesota-based utility that is partnering with Google on the renewable energy and battery storage project.

Google

The tech giant that is developing a new data center complex in Minnesota to be powered by the world's largest battery storage system.

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What they’re saying

“This is the largest announced energy storage project in the world. It definitively confirms the business case for what we call multiday-duration storage.”

— Mateo Jaramillo, Co-founder and CEO, Form Energy (Fortune)

“That 100-hour duration is what's required to provide true, firm capacity into the system. Without that, data center projects would require the construction of excess renewables and short-duration batteries to overcompensate.”

— Mateo Jaramillo, Co-founder and CEO, Form Energy (Fortune)

What’s next

Form Energy is planning to take the company public on a 'relatively near-term horizon', likely next year, as it scales up manufacturing at its new West Virginia factory.

The takeaway

This landmark project demonstrates how long-duration energy storage can finally unlock the full potential of renewable power, allowing it to reliably replace traditional fossil fuel-based baseload generation and support the growth of energy-intensive industries like data centers.