The Canadian company Carbon Engineering has developed a process called "Air to Fuels" (A2F) that absorbs the greenhouse gas carbon dioxide in the air and converts it into oil. The method uses an air capture process that extracts carbon dioxide from the air, thereby purifying it. Electrolysis powered by renewable energy is also used to produce hydrogen from water. The hydrogen and carbon dioxide are then combined through a thermo-catalytic process and synthesised into liquid fuels such as petrol and diesel. This almost climate-neutral fuel represents an alternative to biofuels.