Decarbonisation of electric grids reliant on renewables requires long-duration energy storage

Most climate action centres on getting rid of carbon dioxide. Energy Dome, an Italian startup, wants to put it to use. Its “CO₂ batteries” will store the gas under high pressure when electricity is plentiful; when electricity is needed the stored gas will be run through a turbine to generate some. The advantage of using CO₂ is that it can take on a dense sort-of-liquid form at room temperature; similar systems using other gases need low temperatures. The company has built a pilot plant in Sardinia and is moving up to a commercial scale. “I dream that our domes will become an icon of the energy transition,” says Claudio Spadacini, its charismatic boss, “like windmills and solar panels.”