Abstract

The search and utilization of geothermal energy as a new source of power commenced in Italy in the early 1900's. The first light bulb to be lit by power produced from the natural heat of the earth occurred in 1903. Today, Italy produces sufficient power from geothermal energy to operate its entire network of electric railroads which amounts to approximately 300,000 kw.

Iceland followed Italy in its search for geothermal energy after World War I. Today, domestic and industrial heating is quite common; there is a prospect of a 25,000 kw plant soon to go into operation.

New Zealand produced their first power from geothermal energy in 1958. Their present capacity is approximately 102,000 kw.

In the U. S., between 1921-1925, eight steam wells had been drilled at the Geysers, 75 miles north of San Francisco, California. The project was unsuccessful because abundant, relatively low cost water and fossil fuel generated electric power was available. Between 1956-1958, several of the original wells were reworked and several new wells were drilled. In 1958 the first power plant, with a capacity of 12,500 kw, was installed. A second unit is being installed to boost the capacity to 28,000 kw.

From 1956 to the present time, approximately 97 wells have been drilled in the United States: 73 in California, 19 in Nevada, 3 in Oregon, and 2 in New Mexico.

The deepest geothermal well in the world was completed February, 1962 in the Salton Sea area of California. The temperature gradient averaged about 13° F. per 100', having a maximum temperature of 720° F. at the total depth of 5230'. This well has tapped a very saline brine which has a high concentration of heavy metals and other rare elements. Gold, copper and silver are precipitated during brine production. It has a mass flow rate of 36,000 barrels per day at a well head temperature of approximately 400° F. This one well is capable of producing 10,000 kw of electrical power for an indefinite period of time.

Exploring and drilling for geothermal energy is extremely expensive and hazardous. The cost of drilling and completing a steam well is approximately $50.00/foot.