Near-term and long-term supply curves are presented for electric applications of geothermal energy. The GEOCOST model was used to determine the present and future energy production costs for the high-temperature and intermediate-temperature hydrothermal resources identified by the USGS The long-term supply curves illustrate the potential shifts in the near-term supply curve which would result from certain technology improvements currently being pursued. Programs with the most significant potential impacts are those which result in large reductions in drilling cost, those which lead to development of commercial high capacity downhole pumps, and those which lead to large increases in the plant capacity factor. Curves were drawn to show the impacts of individual technology improvements and also to show the cumulative impacts of combinations of technological advances expected to be achieved by 1982 and 1985. Successful completion of all the programs evaluated would result in a cumulative cost reduction of $90 billion (not discounted) in electrical generating costs from the identified hydrothermal resources