Amos Salvador, 2005, Energy: A historial perspective and 21st century forecast: AAPG Studies in Geology #54, p. 131-147.

DOI:10.1306/1032710SP226

Copyright 2005 by The American Association of Petroleum Geologists.

Energy Consumption and Probable Energy Sources During the 21st Century

Five main factors have guided the preparation of five scenarios of energy consumption and sources of supply in the world during the 21st century:

1) The world's energy resources are estimated to be more than sufficient to supply the demand for energy during the whole century. The issue will be how and where they will be available and how they will be used; efficiently, one hopes, and with minimal damage to the environment.
2) The world human population will grow more slowly but still reach 10–12 billion by 2100. The population of the developing countries will account for 80–90% of the total.
3) A great discrepancy exists in economic development between the developing and developed countries, as testified by the profound divergence of their respective per-capita energy consumption. Because the vast majority of the world population will be in the developing countries, how their economies develop will be critical in estimating the total world energy consumption.
4) No radically new technology for energy generation and use is anticipated; however, important advances in known technologies are expected to make major contributions: clean use of coal, gas-to-liquids conversion, more efficient transport engines and electricity-generation plants, and development of fuel cells powered by hydrogen for transport and electricity generation.
5) Most important, finally, will be how widely governments, industries, and the people recognize the potential damage to the environment by the use of the fossil fuels and how decisively they act to protect it.

During the 21st century, energy will continue to be used principally as transportation fuels and for electricity generation. The fossil fuels (oil, natural gas, and coal) will be the major source of energy supply during the entire century. Other sources are forecast to contribute in different but lesser proportions in the five scenarios.