Energy Dome's CO2 batteries store power for up to 24 hours

Energy Dome uses compressed carbon dioxide in giant domes for long-duration energy storage of up to 24 hours. Its first commercial 200 MWh plant opened in Sardinia in 2025, with 30 GWh of projects planned across five continents. The technology is 10–15% cheaper than lithium-ion for eight-hour storage.

• A dome the size of seven soccer fields holds about 2,000 metric tons of CO2
• The Sardinia plant's 200 MWh can power ~18,000 homes for 10 hours
• Roundtrip efficiency is about 70% versus roughly 90% for lithium-ion
• In June 2026 it signed a deal with Google for a 200 MWh plant in Ireland