enerqy for heating water and homes is believed to be generally competitive hrithoil-fired or electric hot water systems in many of these countries. The clirectconversion of sun rays into electricity through the use of single crystal siliconcells is increasingly the practice in some <ieveloping countries. The investnentcost of this type of photovoltaic deviee is still very high, however. It isgenerally thought that large-scale utilization of photovoltaics, for example forirrigation pumping or as a contribution to centralized grids, would have to dependupon technological breakthroughs and a significant recluction in capital costsper kilowatt. In addition, account should be taken of the storage problem and itscost. The outlook seems favourable in this regard since the price of photovoltaic modules has fallen by about two thirds in the last decade. It is conceivable,furthermore, that, towards the end of the century, a whole nerd generation of solarcells, based on "thin film" technology, will be developed to ..f. po""ible thelarge-scale application of such photovoltaic modules. Similarly, active solarcooling systems, wbich are currentlv less mature technologically than solar heatingsystems, could be developed and applied on a large scale cturing the same period. (S) Wind energy
**Analysis**
The text primarily discusses the utilization of various energy sources, including solar power, wind energy, and traditional methods, with a focus on their cost-effectiveness and potential for large-scale application. It also touches on the technological advancements and breakthroughs needed for widespread adoption. Given the technical and economic aspects of the text, it appears to be more focused on the development of energy solutions rather than other aspects of society.

**Category**
Natural resources and environment, Science and technology