The Carroll Center, a 7700-square-foot preschool and recreation facility in Oak Park, is only the second building in the state to achieve zero energy verification from the New Buildings Institute. That means it produces at least as much energy as it uses. The building is almost like something out of science fiction, with a geothermal heating system reaching 460 feet below the ground, a solar roof and carbon censors that use the CO2 in the air we breathe out to gauge whether alert the ventilation system to release more fresh air. It’s also all-electric, a feature that experts say homes and buildings will have to achieve if we are to radically reduce greenhouse gas emissions by 2050 and protect the planet from the worst effects of climate change.