Forecasting the Mix of World Energy Needs by mid-21st Century

The logistic function is used to forecast energy consumed worldwide. The logistic substitution model is used to describe the energy mix since 1965 presenting a picture significantly different from the one covering the previous 100 years. In the new picture the share of heavy pollutants, i.e. coal plus oil, keeps declining systematically in favor of natural gas and renewables (wind, geothermal, solar, biomass, and waste), the share of which grows rapidly. The shares of these three energy sources (coal plus oil, natural gas, and renewables) are poised to reach around 30 percent each by the mid-21st century. Nuclear and hydroelectric energy, both with rather stable shares, are responsible for the remaining 10 percent, which goes mostly to hydroelectric. Zooming into the composition of renewables we find that today's dominant wind power is about to begin losing share to solar energy, which will overtake wind after 2024 and account for more than 90 percent of all renewables by mid-21st century, by which time geothermal, biomass, and other renewable energy sources will have dropped to insignificant levels. Forecasts in exajouls are given for all energy sources up to 2050.