On the path to a low-carbon economy, most experts agree that a variety of strategies will be needed, from the dramatic expansion of wind and solar power to electrification or better biofuels for cars and planes. Some technologies remain more controversial than others, however. Carbon capture and storage — the idea of trapping carbon dioxide emissions from power plants and other industrial sources before they are released into the atmosphere and then storing them, usually underground — is one such widely debated approach.