18-03-2011, 03:07 PM
ABSTRACT
The search and utilization of geothermal energy commenced in Italy in the early 1900s. Today, Italy produces sufficient power from geothermal energy to operate its entire network of electric railroads. This amounts to approximately 400,000 kw.
One hundred areas in 15 different countries are being explored for geothermal energy. Other countries which are currently utilizing geothermal energy are: Iceland, for domestic and industrial heating; Japan, for electrical power and recovery of salt from sea water; and New Zealand, U.S.A., and Mexico for electrical power.
The Geysers area of northern California was first investigated for its geothermal potential in 1922. The project was not successful as there was sufficient electrical power being produced from fossil fuel and by hydroelectric plants.
The rapid industrialization and population explosion in the western states have led to an increase in demand for energy.
Geothermal energy is used for electric power generation and direct utilization in the United States. The present installed capacity for electric power generation is 3,064 MW with only 2,212 MW in operation due to reduction at The Geysers geothermal field in California; producing approximately16,000 GW\ per year. Geothermal electric power plants are located in California, Nevada, Utah and Hawaii. The two largest concentrations of plants are at The Geysers in northern California and the Imperial Valley in southern California. The direct utilization of geothermal energy includes the heating of pools and spas, greenhouses and aquaculture facilities, space heating and district heating, snow melting, agricultural drying, industrial applications and ground-source heat pumps. The installed capacity is 4,000 MW and the annual energy use is 20,600 billion Btu (21,700 TJ - 6040 GW). The largest applications is ground source (geothermal) heat pumps (59% of the energy use), and the largest direct-use is in aquaculture. Direct utilization is increasing at about six percent per year; whereas, electric power plant development is almost static. Geothermal energy is a relatively benign energy source, displaying fossil fuels and thus, reducing greenhouse gas emissions. A recent initiative by the U.S. Department of Energy, “Geo-Powering the West,” should stimulate future geothermal development. The proposal is especially oriented to small-scale power plants with cascaded uses of the geothermal fluid for direct applications.