Imagine this. The year is 2030 A.D. Renewable energy sources are supplying over 50% of the United States' energy needs. Total energy use has decreased dramatically from its exorbitant 1990's level. Multi-megawatt windfarms, solar thermal farms and biomass plants dot the landscape. Biofuels and solar-derived hydrogen make many of our cars, trains and buses go. Photovoltaic energy technology is converting sunlight directly into electricity in remote locations. Hydropower continues to provide electricity using such technology as run-of-the-river facilities which don't need huge dams. High-temperature and direct-use geothermal energy are household words; and geothermal heat pumps warm homes everywhere.