The first industrial-scale energy storage facility in the U.S. based on CO₂ is underway.

Wisconsin Makes Its Mark on the U.S. Energy Map

The state of Wisconsin is increasingly making its presence felt on the U.S. energy landscape. The Public Service Commission (PSC) has just approved the Columbia Energy Storage project—the nation’s first industrial-scale deployment of an innovative energy storage technology using carbon dioxide. The initiative is led by Alliant Energy in collaboration with Energy Dome, Wisconsin Public Service Corporation, and Madison Gas and Electric.

Project Details

The project will be implemented near the existing Columbia Energy Center in the town of Pacific, south of Portage. It aims to deliver up to 200 MWh of energy—enough to power approximately 18,000 households for 10 hours on a single charge cycle.

Energy from… CO₂?

At the heart of the project is a proprietary technology developed by the Italian startup Energy Dome, which uses carbon dioxide as the storage medium. In simplified terms: when there is an excess of electricity, CO₂ is compressed and stored in liquid form. When demand rises, the process is reversed—the gas expands, driving a turbine and generating electricity.

The system operates in a closed loop, is completely emission-free, safe, and—most importantly—offers long lifespan and high cycle efficiency. It addresses the limitations of lithium-ion batteries, particularly in the context of long-duration energy storage and enhancing grid resilience.

A Broader Strategy

The project is part of Alliant Energy’s broader Energy Blueprint strategy, which focuses on building a sustainable energy mix based on renewables and advanced storage. It also underscores that the future of energy is not only about building wind and solar farms, but—perhaps more importantly—about integrating those sources with flexible and scalable storage systems.

Construction Starts in 2026

The project is slated to begin construction in 2026, with completion expected by the end of 2027. Once operational, the system will be one of the first of its kind in the world and will likely serve as a benchmark for future LDES (Long Duration Energy Storage) initiatives.

Wisconsin is already establishing itself as a hub of clean energy innovation—not through political declarations, but through concrete, pioneering actions undertaken by local energy companies.