The long-range prospects for solar energy

An attempt is made to evaluate the long-range potential of various ways of using solar energy. Assuming the technology to be successfully established, the question is posed whether solar energy systems can be commercially feasible as a practical component of the nation's energy system in competition with alternative energy sources. In discussing direct uses of solar radiation, including solar heating and solar electricity systems, the energy conversion efficiency, problems related to low intensity and intermittency of solar energy are analyzed, as well as land requirements for solar-electric power plants. The major trends and prospects of wind power plants, and the Ocean Thermal Energy Conversion (OTEC) system are examined as examples of indirectly used solar energy. Attention is also given to space-based solar electric systems. It is concluded that neither direct nor indirect solar energy (other than hydroelectric) can make a substantial contribution to the nation's large-scale energy needs. Potential of solar energy is found to be significant only for small self-contained total energy systems for rural homes and farms, or in remote locations where the cost factor is not important.