ABSTRACT
Having now reviewed some of the key technical options, what is the overall scale of the renewable energy resource? The simple message is that the basic energy source is very large. The sun delivers a vast amount of energy to the earth – much more than could ever be used, and the resultant natural energy flows represent a very large, non-finite resource base, with the solar radiation input alone amounting to around 90,000 TW. For comparison, total global energy consumption in 1990, measured on a continuous equivalent power basis, was only 13.5 TW.
