Oil Shale

The energy resources of the world consist of contemporary solar radiation; the fossil fuels: coal, oil and gas, tar sands and oil shales; and nuclear energy from the fissionable elements uranium and thorium, and from the fusion of the light element deuterium. The fossil fuels represent stored solar energy accumulated during the past 500 million years. According to current geological esti-mates, the initial supplies of the various kinds of fossil fuels, prior to human exploitation, which are producible by present methods, were approximately the quantities shown in Table 1