The Columbia Energy Storage Project at Energy Dome in Pacific, Wisconsin, is using carbon dioxide to store energy in a whole different way. Partnered with U.S. energy supplier Alliant Energy, the project's main aim is to store energy for up to 24 hours, offering a solution that surpasses the common 4-hour limit seen in lithium-ion battery systems.

At the core of the system is supercritical CO2, a compressed and liquified form of carbon dioxide. This closed-loop process captures and stores CO2, which is then converted into electricity by expanding the gas through a turbine. Afterward, the CO2 is returned to storage - all of this implying that the system is highly reusable. The innovation addresses the challenge of managing energy produced from intermittent sources like wind and solar, enabling better integration of renewables into the power grid, hopefully for a longer term.

Recognized by Bloomberg NEF’s Pioneers program in 2022 for its low-carbon technology innovation, Energy Dome’s project caught the attention of the U.S. Department of Energy. In July 2024, the Energy Department received a funding of $7 million to support Phase I of the project. Its main focus is on planning and community engagement over the next 16–22 months. This funding is part of a larger cost-sharing program to promote renewable energy growth.

Alliant Energy expects the Columbia Energy Storage Project to help smooth out fluctuations in renewable energy generation, further supporting its efforts to increase renewable energy capacity. The project is considered the first of its kind in the U.S. - which means it's a pretty big deal, especially for long-term, carbon-based energy storage systems.