The key component of this technology is as unlikely as the remote location: carbon dioxide, the chief cause of global warming. Energy Dome, a start-up based in Milan, runs an energy-storage demonstration plant that helps to address a mismatch in the local electricity market. “In Sardinia during the day, everyone goes to the sea,” Claudio Spadacini, chief executive of Energy Dome, said. Energy Dome uses carbon dioxide held in a huge balloon, the “dome” in the company’s name, as a kind of battery. Companies are developing and marketing varied and creative ways to store renewable energy: liquefying carbon dioxide, de-rusting iron, heating towers filled with sand to temperatures almost hot enough to melt aluminum.

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Persons: Clint Eastwood, Claudio Spadacini, “, Jennifer M, Granholm, we’ve, ”, Elaine Hart Organizations: Energy Locations: Sardinia, Ottana, Milan, “, U.S