Google Back Long-Duration CO₂ Battery Technology, Challenging Fossil Fuels and Lithium-Ion Giants

Google is backing a new form of long-duration energy storage powered by compressed CO₂, posing a major challenge to both fossil fuel power plants and conventional lithium-ion battery systems like Tesla’s Megapack. The move signals a growing shift in how renewable energy can be stored and dispatched—especially for high-consumption facilities such as data centers.

Why Long-Duration Storage Matters

Long-duration storage systems—those capable of supplying electricity for 10 hours or more—are increasingly critical as wind and solar power grow. These renewable sources are intermittent by nature, and while lithium-ion batteries are good for 4-hour cycles, they fall short of the needs of a renewable-dominated grid.

The U.S. Department of Energy has long emphasized the need for multi-day or even seasonal energy storage to ensure grid reliability. Until now, pumped hydropower—with its geographic constraints—has dominated the U.S. utility-scale storage landscape.

Enter Energy Dome’s CO₂ Battery

Italian startup Energy Dome has introduced a game-changing solution using supercritical CO₂. The process involves storing CO₂ gas in a dome structure. During charging, the gas is compressed into a liquid state using ambient temperature, avoiding the need for cryogenic cooling. To discharge, the liquid CO₂ is evaporated and sent through a turbine to generate electricity, before returning to the dome.

The closed-loop system is scalable, location-flexible, and targets 8–24 hours of storage—a clear leap ahead of lithium-ion alternatives.

First U.S. Deployment in Wisconsin

Energy Dome’s first U.S. project, the Columbia Energy Storage Project, will be built in Pacific, Wisconsin, in partnership with Alliant Energy, and supported by WEC Energy Group and Madison Gas and Electric.

The project recently received regulatory approval from the Public Service Commission of Wisconsin and is scheduled for operation in 2027. It will supply enough electricity to power around 18,000 homes for 10 hours on a single charge.

According to Alliant:

“This project will enhance grid stability and resilience with next-gen technology from Energy Dome.”

Google’s Support Sends a Strong Signal

Though not directly involved in the Wisconsin project, Google has shown clear interest in Energy Dome’s technology. A pilot facility in Italy has been in operation for over three years, and a new 20 MW commercial plant has just been launched in Sardinia.

Google’s support reflects growing demand for clean, reliable backup power at data centers, which require stable energy beyond the capability of solar panels alone. With its vast global infrastructure, Google’s investment suggests that CO₂-based long-duration batteries could become a mainstream storage solution.

Implication: As solar and wind become cheaper and more prevalent, energy storage that can last for many hours—like Energy Dome’s CO₂ battery—threatens the role of natural gas in balancing the grid. What once helped push coal off the U.S. power system may now find itself next in line.