Renewables in the U.S. Energy Future: How much, how fast?

Recent major studies of the U.S. Energy Future have yielded estimates of the potential contribution of renewable energy sources in this country by the year 2000 ranging from 0.1 to 25 quadrillion Btu (quads) per year, exclusive of geothermal and hydropower. In this article, I compare the assumptions, methods, and detailed findings of a number of these studies in order to illuminate the reasons for real and apparent disagreements. The methods used in the studies ranged from literature review combined with author judgment to elaborate energy-economic models. Not surprisingly, key assumptions involved the price of oil, coal, and nuclear power through the year 2000, costs of various technologies for harnessing renewables in this period, and the presence or absence of nonmarket incentives for renewables based on perceived advantages of these sources other than cost. After disentangling the assumptions and findings of the various studies on a source-by-source basis, I find that the contribution of renewables in the U.S. in the year 2000 probably will fall in a narrower range, from 4 to 18 quads per year. Policies in force at the end of the Carter Administration probably would have produced an intermediate figure of about 8 quads per year; the lower limit of 4 quads per year corresponds to imposition and continuation of the sort of reduced incentives that seem at this early stage to represent the policy of the Reagan Administration. Arguments are adduced here to suggest that sound public policy would seek to achieve the opposite, a societal commitment to implementation of the most attractive renewables-based technologies, aiming to produce perhaps 15–18 quads per year in the year 2000 and increasing amounts thereafter.