Solar energy systems : assessment of present and future potential

Average insolation levels are between 2 and 4 orders of magnitude higher than the specific demand for primary energy in both the industrialized and the developing world. This suggests that solar conversion technologies have a very considerable potential for application, provided that questions of storage and instantaneous release upon request can be adequately addressed. The present state and the future potential of solar thermal and photovoltaic (PV) technologies are discussed, and both the environmental implications of these technologies and the economics that determine their viability in the energy market are examined. Although some significant cost reductions have been achieved, particularly in PV technology, solar conversion technologies are still not generally competitive against conventional fuels, and future cost reductions may be limited. It is argued that fiscal measures will be necessary if solar conversion technologies are to make a significant global impact.