The widespread use of solar thermal energy systems poses a novel challenge for utility planners. The changes will stem from the fact that occasionally at night and on cloudy days, solar users with inadequate storage capacity will be forced to rely on conventional energy sources - electrical resistance heating, oil, or gas. Thus, while the average electricity demand may be reduced, infrequent demand peaks may be very high. Major concerns of the industry include the adverse effect of solar thermal heating on revenues from the sale of electricity, and the probable need to maintain or even increase high levels of generating capacity. Though the advent of solar energy promises some difficulties for utilities in the short term, it is in their long-range interests to encourage on-site solar heating for several reasons: the utilities will find solar energy a new source of leverage in pressing for badly needed progressive rate reform; solar energy represents opportunities for the utilities to avoid investments in new capacity that may never be recovered and solar heating could be considered a means for utilities to meet their responsibility to satisfy the energy needs of their customers.
