CO2 Battery startup Energy Dome’s 10-hour Wisconsin battery approved

July 22, 2025
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Energy Dome and Alliant Energy’s 20MW/200MWh long-duration energy storage (LDES) project in Wisconsin, US, has been approved by state regulators.

The Columbia Energy Centre project is located in Pacific, Wisconsin, close to an Alliant Energy-managed coal plant in Portage, Wisconsin.

A coalition comprising two other Wisconsin utilities—WEC Energy Group and Madison Gas & Electric—Shell Global Solutions, the US Electric Power Research Institute, and two academic institutions is working on developing the project.

The project will utilise Energy Dome’s CO2 Battery technology, which stores energy via the adiabatic compression of carbon dioxide. During charging, the gas is liquefied, and during discharging, it evaporates as part of a thermodynamic cycle.

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Alliant and Energy Dome signed a supply contract for the project in October 2024. The project application was filed with the regulatory Public Service Commission (PSC) of Wisconsin in August of the same year.

Construction on the 10-hour project is expected to begin in 2026 and be completed by the end of 2027.

Energy Dome is building a system of the same size in Sardinia, Italy, where the company has delivered its only commercial-scale project thus far. That 2.5MW/4MWh project went online in 2022.

Notably, the Wisconsin project was chosen by the US Department of Energy’s Office of Clean Energy Demonstrations (OCED) in 2023 to receive US$30 million in funding from a total pledge of US$325 million aimed at supporting LDES technologies.

Following this selection, the European Investment Bank (EIB) and Breakthrough Energy Ventures committed €60 million (US$65.37 million) to Energy Dome’s Sardinia project, contingent on specific conditions.

This year, it was announced that National Thermal Power Corporation (NTPC) will deploy a 20MW/160MWh Energy Dome project at a power plant in Karnataka, India

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