Columbia Energy Storage Project
The Columbia Energy Storage Project is the first long-duration energy storage system of its kind to be developed in the United States. The 18-megawatt project is designed to improve grid stability and deliver enough electricity to power approximately 18,000 homes for 10 hours on a single charge.
The added reliability and dispatchability provided by the project will help to further enable MGE's ongoing transition toward greater use of carbon-free energy. It also will help to manage long-term customer costs because projects like this one enable the partner utilities to store energy to help meet peak demand.
The project will use a revolutionary closed-loop process, designed by Energy Dome, to take energy from the grid and convert carbon dioxide (CO2) gas into a compressed liquid form for long-term storage. Then, when the stored energy is needed, the system will convert the liquid CO2 back to a gas, which will power a turbine to create electricity.
The project will be built south of Portage in the Town of Pacific, near the current Columbia Energy Center, which is co-owned by Alliant Energy, Wisconsin Public Service (WPS) and MGE. MGE is a minority owner of the power plant. This site allows the use of existing electrical infrastructure while the partners work to advance the next generation of sustainable energy.
The project received approval from the Public Service Commission of Wisconsin in June 2025. Construction is expected to begin in 2026 and be completed by the end of 2027.
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