Growth in global energy demand and contribution of alternative supply systems

Abstract

Growth in global energy demand since the end of World War II has been nearly constant at a rate of 5.3% each year. When energy demand is projected into the future, the basic question is how long such an exponentially growing global energy use can continue, and a more accurate analysis than projecting exponential growth indefinitely into the future is certainly desirable. In this analysis, nine political/geographical segments are used and it is shown that the less developed countries will grow much more rapidly than the industrialized countries. Analyses of individual nations- or at least small sub-divisions of the nine segments—based on factors such as population growth, availability of resources, capability of food production, potential for formation of capital, and prospects for political stability are necessary in order to achieve reasonable accuracy in projections. Such concepts of growth suggest very strongly that fifty years from now the global energy demand will be approximately 31 TW, with over half the total coming from the developing world. This will present unusual opportunities for employing alternative energy supply systems. In rapidly growing situations, market penetration of new technologies is easier, but, in any event, the magnitude of the effort required is enormous if alternative supply systems are to make major contributions to the total. As a target, the 17 TW demand in AD2025 from the developing world might be met by the following supply system: TW Solar Heating (water and air) 1.5 Biomass (firewood, charcoal, alcohol) 3.5 Wind 0.8 Hydro and Geothermal 2.2 Fission 0.5 Fossil fuels (oil, gas, coal) 8.5 Total 17.0 To place these in perspective and to indicate the size of the task involved, note that the total world energy demand in 1975 was only 7.3 TW. The target calls for alternative supply systems in the developing world alone to exceed the present world total within 50 yr. Contributions from hydro and geothermal sources (in the developing world) approach the present total energy demand in North America—one-third of the world's total. Biomass as a supply system is targeted for 1.5 times the present N. American total. While this is a formidable target, I believe that if economic growth throughout the world is to continue and if the gap between the rich and poor countries is to shrink, it is, in fact, a modest social goal.