The International Energy Outlook 2013 (IEO2013) projects that world energy consumption will grow by 56 percent between 2010 and 2040. Total world energy use rises from 524 quadrillion British thermal units (Btu) in 2010 to 630 quadrillion Btu in 2020 and to 820 quadrillion Btu in 2040.
Much of the growth in energy consumption occurs in countries outside the Organization for Economic Cooperation and Development (OECD), known as non-OECD, where demand is driven by strong, long-term economic growth. Energy use in non-OECD countries increases by 90 percent; in OECD countries, the increase is 17 percent. The IEO2013 Reference case does not incorporate prospective legislation or policies that might affect energy markets.
Renewable energy and nuclear power are the world's fastest-growing energy sources, each increasing by 2.5 percent per year. However, fossil fuels continue to supply almost 80 percent of world energy use through 2040. Natural gas is the fastest-growing fossil fuel in the outlook. Global natural gas consumption increases by 1.7 percent per year. Increasing supplies of tight gas, shale gas, and coalbed methane support growth in projected worldwide natural gas use. Coal use grows faster than petroleum and other liquid fuel use until after 2030, mostly because of increases in China's consumption of coal and tepid growth in liquids demand attributed to slow growth in the OECD regions and high sustained oil prices.
The industrial sector continues to account for the largest share of delivered energy consumption; the world industrial sector still consumes over half of global delivered energy in 2040. Given current policies and regulations limiting fossil fuel use, worldwide energy-related carbon dioxide emissions rise from about 31 billion metric tons in 2010 to 36 billion metric tons in 2020 and then to 45 billion metric tons in 2040, a 46-percent increase.
World energy-related carbon dioxide emissions rise from 31.2 billion metric tons in 2010 to 36.4 billion metric tons in 2020 and 45.5 billion metric tons in 2040 in the IEO2013 Reference case—an increase of 46 percent over the projection period. With strong economic growth and continued heavy reliance on fossil fuels expected for most non-OECD economies under current policies, much of the projected increase in carbon dioxide emissions occurs among the developing non-OECD nations. In 2010, non-OECD emissions exceeded OECD emissions by 38 percent; in 2040, they are projected to exceed OECD emissions by about 127 percent. Coal continues to account for the largest share of carbon dioxide emissions throughout the projection.
Carbon intensity of output—the amount of carbon dioxide emitted per unit of economic output—is a common measureit is sometimes used as a stand-alone measure for tracking progress in relative emissions reductions. Energy-related carbon dioxide intensities improve (decline) in all IEO regions over the projection period, as economies continue to use energy more efficiently. Estimated carbon dioxide intensity declines by 1.9 percent per year in the OECD economies and by 2.7 percent per year in the non-OECD economies from 2010 to 2040.