Transporting the terajoules: Efficient energy distribution in a post-carbon world

In a post-carbon energy economy, just as during the Age of Fossil Fuel, the locations where men take control of energy resources (e.g., the coal-pit, the mill wheel, the terminals of a concentrating solar power generator) will often be far removed from the locations where they wish to expend those resources. Therefore, the captured energy resource, once isolated, must somehow be translated from its point of origin to its point of use; and in doing so, its owner must expend energy. In this paper it is argued that, in a sustainably fueled future: (i) renewable energy in its initially transportable form will be overwhelmingly electrical; (ii) energy frugality will dictate long-distance transport of energy as electricity; (iii) intermediate-term (less than a fortnight) storage of energy will be via compressed air energy storage or pumped hydro- or electrochemical batteries, which can not be comparatively evaluated without extensive expensive development and demonstration; and (iv) massive conversion of electrical energy into synthetic fuels will be restricted to selected transportation applications.