| Abstract: | Over the next hundred years there must be a worldwide transition from reliance on fossil fuels to the use of some combination of long-term and abundant primary sources for the production of heat, electricity, and synthetic fuels. The rate at which such options can be developed and employed, as well as the maximum rate at which they can provide energy at a sustained rate, will place important constraints on the rate and limits to growth of other human activities. It is generally argued that only the fission option, in the form of the fast-breeder and high-temperature reactors, can provide the energy required for a livable world, particularly if this means a world of 10 billion people living at the present energy level of Western Europe. However, a careful examination indicates that the use of solar energy, through a menu of technological options, can provide the needs of a world at this scale of energy use, and that this can be accomplished within the constraints of land availability and requirements for energy, materials, and labor. No scientific breakthroughs are required, although a number of these would be helpful, but very substantial engineering advances are required, and the transition of such a world-wide system would take no less than a century. However, the feasibility of such large-scale use of solar energy will substantially alter those aspects of the “limits to growth” discussions in which future growth strategies are constrained by available and acceptable energy alternatives. This paper outlines a global solar-energy system considered feasible for more than 10 billion people living at 5 kW per capita. |
