There’s a growing need for long-duration storage to balance renewables on the grid. Energy Dome uses compressed carbon dioxide gas in its massive grid batteries, delivering power for up to 24 hours. Solar and wind power are cheap but intermittent, and Energy Dome smooths supply-demand gaps.
The key component is a huge white dome, about the size of seven soccer fields, holding 2,000 metric tons of carbon dioxide. When energy is available, compressors liquefy the gas, storing it in tanks. Heat is captured in a proprietary material. When power is needed, the gas is warmed, expands through a turbine to generate electricity, and returns to the dome.
Compressed-air storage isn’t new, but Energy Dome’s approach needs no specific geology, aiding scalability. Its first commercial plant in Sardinia, Italy (2025) has 200 megawatt-hours capacity, powering about 18,000 homes for 10 hours. Founded in 2020, headquartered in Milan, it plans 30 gigawatt-hours across five continents.
Energy Dome claims costs are 10-15% cheaper than lithium-ion for eight-hour systems, using off-the-shelf equipment. However, only one commercial plant operates, and roundtrip efficiency is about 70% versus lithium-ion’s 90%. A natural-gas-turbine variant emits greenhouse gases.
Source: MIT Technology Review · Summarized by HeadlinesBriefing