University of Wisconsin-Madison

From the graph it is apparent that oil, and natural gas will not last the full 21 Century and in fact may be "effectively" exhausted for the World market by ~2050. Large increases in coal consumption are required after ~2020 to satisfy the world wide needs for liquid and gaseous fuels. There is a gap between what is available and what is required that begins to develop by ~ 2060 and if we wish the 5 trillion boe of coal to last thru the end of the 21st Century, then a new energy source is needed in the latter part of the next Century. This new energy source, must produce ~ 75% of the world wide energy in 2100. (Remember, this is in addition to requiring that the hydro, fission, wind, and other sources provide 14% of the World energy during that time period).