English: Global energy potential. comparing renewable and non-renewable energy sources by their potential. The area of the circles is proportional to the amount of energy they represent. Renewable sources show their power potential in terawatts (TW) and finite sources their estimated reserves in terawatt-years (TW-yr). Worldwide energy consumption of 15.97 TW for 2013 translates into 139,891 TWh or 12730.4 Mtoe. Non-renewable resources available were scaled by 30 years for comparison with renewable resources (if all of it was consumed in 30 years, the area of the circle shows how much would be available each year). Only coal would last longer than 30 years if it was our only energy source, and only wind and solar could individually supply all of our energy. Solar can supply thousands of times what is used. More energy is available from the Sun in an hour than is used in a year.