Closely related to energy consumption is the concept of total primary energy supply ( TPES ) , which – on a global level – is the sum of energy production minus storage changes . Since changes of energy storage over the year are minor , TPES values can be used as an estimator for energy consumption . However , TPES ignores conversion efficiency , overstating forms of energy with poor conversion efficiency ( e.g. coal , gas and nuclear ) and understating forms already accounted for in converted forms ( e.g. photovoltaics or hydroelectricity ) . The IEA estimates that , in 2013 , total primary energy supply ( TPES ) was 1.575 & times ; 1017 Wh ( = 157.5 PWh , 157,500 TWh , 5.67 & times ; 1020 joules , or 13,541 Mtoe ) or about 18 TW-year . From 2000 – 2012 coal was the source of energy with the total largest growth . The use of oil and natural gas also had considerable growth , followed by hydropower and renewable energy . Renewable energy grew at a rate faster than any other time in history during this period . The demand for nuclear energy decreased , in part due to nuclear disasters ( Three Mile Island in 1979 , Chernobyl in 1986 , and Fukushima in 2011 ) . More recently , consumption of coal has declined relative to renewable energy . Coal dropped from about 29 % of the global total primary energy consumption in 2015 to 27 % in 2017 , and non-hydro renewables were up to about 4 % from 2 %
Three Mile Island
Three Mile Island accident
World energy consumption