Number 1 (Story #5), September 28, 1990 by Phillip F. Schewe and Ben Stein SOLAR CELLS may be better at converting sunlight into heat than into electricity, some researchers believe. The record efficiency for conversion to electricity, a tandem GaAs and Si cell at Sandia, is 31%. The theoretical limit is thought to be 40%. But thermal conversion may be more efficient and, besides, a great deal of the world's energy consumption goes toward the production of heating anyway. (New Scientist, 22 September, p. 48)