tionary 1,300-MW units and mid-size 650-MW units), to be available for order by the mid-1990s. Modular high-temperature gas reactor and advanced liquid metal reactor designs are under development. Although these designs may be available as early as 2005, their adoption is uncertain. While concern over greenhouse gas emissions could increase the attractiveness of nuclear power plants relative to coal, the economic and environmental issues associated with plant operation and waste disposal are likely to impede any significant growth of nuclear capacity in the near to mid-term. In the committee's base scenario, significant deployment of new nuclear power plants is unlikely until after 2020.
Considering installed and anticipated nuclear power plants in the United States and worldwide, there is no prospect of a uranium shortage before 2020. However, a significant expansion of nuclear power thereafter could challenge accessible uranium supplies. If supply constraints forced up uranium prices after 2020, the continued use of nuclear-based electricity would require technology development on fast breeder reactors and fusion reactors. The support of further development and use of nuclear power in the United States and worldwide will depend on growth in overall electricity demand, regulatory evolution, the direction of the global climate change debate, and resolution of public concerns with operational safety and waste disposal. Policy actions that increase the cost of fossil fuel use would make nuclear power more competitive.
Most electricity from renewable resources in the United States comes from hydroelectric power, which in 1993 accounted for about 10 percent of installed generating capacity and 9 percent of electricity generation. Other renewable sources accounted for 0.3 percent of electricity generation in 1993: geothermal, biomass wastes (almost all forest industry, with a small contribution from municipal solid waste), modest but growing amounts from wind turbine "farms," and distributed high-value, high-cost, solar photovoltaic power.
Cost reductions in renewables have resulted from persistent R&D, field experience, and manufacturing automation made possible through federal and private investments. EPRI has projected cost ranges for wind, photovoltaic, and biomass, assuming favorable locations (Table 3-7). These data indicate likely decreases in cost over the next 15 years, together with changes in the relative economics of different renewable sources. Although wind and biomass may be attractive for specific applications in favorable locations, it is clear that renewables could not meet energy demands across the economy as a whole (Preston, 1994). Many utilities look at renewable technologies as a strategically valuable set of contingency options if prices rise substantially or fossil fuel use is curtailed. For example, policy actions to tax emissions would make renewables more competitive. While renewable energy sources are expected to gain a larger share of the U.S. power generation market (16 percent by 2010, according to EIA, 1994a),