First Geothermal Power Plant Begins Operation

Date 1913

The first geothermal power installation was inaugurated when hot springs in northern Italy were used to provide steam to power an electric generator.

Locale Larderello, Italy

Key Figures

• Piero Ginori Conti (1865-1939), Italian nobleman and industrialist
• Charles Parsons (1854-1931), English engineer

Summary of Event

It has been known since ancient times that the interior of the earth is hot. Hot springs have been prized for centuries for their supposed curative powers and have been used occasionally for cooking and heating, but attempts to utilize the earth’s internal heat on a large scale did not become practical until the twentieth century. Drilling into a reservoir of high-pressure steam requires techniques that will protect the drillers. Also, because most geothermal steam sources are not near large population centers, tapping geothermal energy did not become practical until electric power networks were available to transport the energy harnessed.

The first successful use of geothermal energy took place at Larderello in northern Italy. The Larderello geothermal field, located near the city of Pisa about 149 miles (240 kilometers) northwest of Rome, contains many hot springs and fumaroles (steam vents). In 1777, these springs were found to be rich in boron, and in 1818 Francesco de Larderel began extracting borax from them. Previously, the principal source of borax for Europe had been remote Tibet. In the beginning, wood fires were used to evaporate water from the geothermal brine, but in 1827 Larderel began using steam from the fumaroles as a source of heat as well. Soon afterward, wells were drilled to increase the flow of mineralized water and to obtain more steam. Attempts were made also to use geothermal steam to power steam engines, but these failed because the water was too corrosive. Borax extraction at Larderello continued until 1969.

Shortly after 1900, Prince Piero Ginori Conti, director of the Larderello borax works, conceived the idea of using the steam for power production. An experimental power plant was constructed at Larderello in 1904 to provide electric power to the borax plant. After this initial experiment proved successful, a 250-kilowatt generating station was installed in 1913, and commercial power production began. As the Larderello field grew, additional geothermal sites throughout the region were prospected and tapped for power. Power production grew steadily until the 1940’s, when production reached 130 megawatts; however, the Larderello power plants were destroyed late in World War II. After the war, the generating plants were rebuilt, and by 1980 they were producing more than 400 megawatts.

The Larderello power plants encountered many of the technical problems that were later to plague other geothermal facilities. For example, hydrogen sulfide in the steam was highly corrosive to copper, so the Larderello plants used aluminum for electrical connections much more than did conventional power plants of the time. Also, the low pressure of the steam in early wells at Larderello presented problems. The first plants simply used steam to drive generators and vented the spent steam to the atmosphere. A system of this sort, called a noncondensing system, is useful for small generators but not efficient to produce large amounts of power. Most steam engines derive power not only from the pressure of the steam but also from the vacuum created when the steam is condensed back to water. Geothermal systems that generate power from condensation as well as direct steam pressure are called condensing systems. Most large geothermal generators are of this type.

Condensation of geothermal steam presents special problems not present in ordinary steam engines. One problem is the presence of other gases that do not condense. Instead of a vacuum, condensation of steam contaminated with other gases results in only a limited drop in pressure and, consequently, very low efficiency. Initially, the operators of Larderello tried to use the steam to heat boilers that would, in turn, generate pure steam. Eventually, they developed a device that removed most of the contaminating gases from the steam. Although later wells at Larderello and other geothermal fields produced steam at greater pressure, the engineering innovations developed at Larderello improve the efficiency of any geothermal power plant.

In 1913, the English engineer Sir Charles Parsons proposed drilling an extremely deep (7.5-mile or 12-kilometer) hole to tap the earth’s deep heat. Power from such a deep hole would not come from natural steam as at Larderello, but would be generated through the pumping of fluid into the hole to generate steam (as hot as 500 degrees Celsius) at the bottom. In modern terms, Parsons proposed tapping “hot-dry-rock” geothermal energy. By the end of the twentieth century, no such plant had yet been commercially operated, but research was being actively pursued in several countries.

The second geothermal field to produce electric power was Beppu, on the island of Kyushu in southern Japan. Initial studies began in 1919, and a small one-kilowatt power plant began producing power in 1924. A large number of geothermal power plants have been constructed in Japan, but despite its pioneering role in developing Japanese geothermal power, the Beppu field has not developed into a major energy producer.

In the 1930’s and 1940’s, geothermal facilities were developed in Iceland and New Zealand. Although geothermal electrical generating plants were built in both countries, much of the geothermal energy was used directly for heating. As of 2005, two of the most extensive systems were in place in Reykjavik, Iceland, and Rotorua, New Zealand, where water is piped from geothermal wells to homes and businesses. More than 60 percent of Iceland’s population receives home and business heating from geothermal sources. Iceland is uniquely suited to exploit geothermal energy because of its small population (about 240,000) and abundant geothermal heat. Somewhat surprisingly, Iceland has been slow in developing geothermal electricity because hydroelectric power has been sufficient for the population’s needs.

The first use of geothermal energy in the United States was for direct heating. In 1890, the municipal water company of Boise, Idaho, began supplying hot water from a geothermal well. Water was piped from the well to homes and businesses along appropriately named Warm Springs Avenue. At its peak, the system served more than four hundred customers, but as cheap natural gas became available, the number declined. By 1972, only two hundred customers remained, and the water company was planning to discontinue operations when a citizens’ group purchased the water rights to the well and launched a program to expand operations. Around the beginning of the twentieth century, some individual residents of Klamath Falls, Oregon, began drilling geothermal wells to heat their own buildings.

Although Larderello was the site of the first successful geothermal electric power plant, the modern era of geothermal electric power began with the opening of the Geysers geothermal field in California, which marked the start of commercial geothermal power generation in the United States and the beginning of commercial geothermal power generation on a worldwide basis. The field of geysers located about 68 miles (110 kilometers) north of San Francisco was discovered by explorer William Bell Elliott in 1847, and by the end of the nineteenth century, the area had become a tourist resort, with visitors including Theodore Roosevelt and Mark Twain. In the 1920’s, John D. Grant, John Debo Galloway, and Fred Stone made test borings to explore the possibility of power production; although they were successful, the geothermal source could not compete with inexpensive power from hydroelectric and fossil-fuel power plants. Also, the field of geysers was too isolated to be a commercially viable source of electric power.

In 1955, B. C. McCabe, a Los Angeles businessman, leased 5.6 square miles (14.6 square kilometers) in the geysers area and founded the Magma Power Company. Dan A. McMillan of the Thermal Power Company joined with McCabe in exploration, and, in 1958, McCabe and McMillan contracted with the Pacific Gas and Electric Company to produce steam for power generation. The first 12.5-megawatt generator was installed at the Geysers field in 1960, and production increased steadily from then on. The California field surpassed Larderello as the highest-producing geothermal field in the 1970’s, and by 1980 it was generating more than 1,000 megawatts. By the end of the twentieth century, geothermal plants installed in twenty-one countries were producing more than 8,200 megawatts to supply energy to about sixty million people.

Significance

Geothermal power has many attractive features. Because the steam is naturally heated and under pressure, generating equipment can be simple, inexpensive, and quickly installed. Equipment and installation costs are offset by savings in fuel. The installation of small generators is economically practical, a fact that makes the establishment of geothermal plants attractive in remote or underdeveloped areas. Most important to a world faced with a variety of technical and environmental problems connected with the use of fossil fuels, geothermal power does not deplete fossil-fuel reserves, produces little pollution, and contributes little to the greenhouse effect.

Although it has been significant to local power production, geothermal power has not had a very great global impact, accounting for only a small percentage of the world’s total electric power production. Despite its attractive features, geothermal power has some limitations. Geologic settings suitable for easy geothermal power production—where hot rock or magma bodies are close to the surface—are rare. Although it is technically possible to pump water from an external source into a geothermal well to generate steam, most geothermal sites require a copious supply of natural underground water that can be tapped as a source of steam. In contrast, a fossil-fuel generating plant can be built at any convenient location.

The technical difficulties associated with exploiting geothermal power are considerable. Drilling into hot rock is much more difficult than ordinary drilling, as the high temperatures wear out drilling equipment rapidly, and safety precautions are necessary to protect workers during drilling. Fortunately, unlike oil wells, geothermal wells generally do not need to be very deep, usually only a few hundred meters. Geothermal power is not unlimited; a geothermal reservoir can be depleted by excessive consumption just as any other natural resource can be depleted. In addition, the hot underground water is often highly mineralized, capable of corroding or clogging pipes and even of sealing the underground fractures that make the water accessible. If the water is highly laden with minerals, disposing of it can create a pollution problem, although it is possible to deal with much of this problem by injecting the fluid back into the ground through disposal wells.

A fundamental limit on geothermal power is set by the second law of thermodynamics, which defines how much useful work can be obtained from any physical process. Any physical process powered by heat converts heat into some other form of energy. In the process, the temperature of the heat source is lowered. The thermodynamic efficiency of any process powered by heat is equal to the temperature drop divided by the original temperature. Fossil-fuel and nuclear power plants are used to create very hot steam so that a large temperature drop is possible, resulting in high efficiency. Most geothermal sources produce steam that is not far above the boiling point of water; geothermal generators cannot achieve a very large drop in temperature and thus have low efficiency. The unavoidable energy losses caused by friction and heat dissipation further reduce the actual efficiency of most geothermal power plants.

Bibliography

Armstead, H. Christopher H. Geothermal Energy: Its Past, Present, and Future Contributions to the Energy Needs of Man. 2d ed. London: E. and F. N. Spon, 1983. A general overview of geothermal power and methods of utilizing it. Begins with a history of geothermal power and describes techniques for drilling and power production. Several chapters describe case histories of developed geothermal fields up to the 1980’s.

Barnea, Joseph. “Geothermal Power.” Scientific American 226 (January, 1972): 70-77. An overview of the technology of geothermal power production. Describes techniques for locating geothermal heat sources and methods of extracting power from different types of geothermal fields.

DiPippo, Ronald. Geothermal Energy as a Source of Electricity: A Worldwide Survey of the Design and Operation of Geothermal Power Plants. U.S. Department of Energy Report RA 28320-1. Washington, D.C.: Government Printing Office, 1980. A country-by-country survey of geothermal power projects. The descriptions of the facilities are often quite technical, but there are also historical summaries, maps, and tables of power production.

‗‗‗‗‗‗‗. Geothermal Power Plants: Principles, Applications, and Case Studies. New York: Elsevier Science, 2005. A technical discussion of all aspects of the geothermal energy industry.

Garrett, Wilbur E., ed. “Energy: A Special Report in the Public Interest.” National Geographic, February, 1981. A general survey of energy resources, usage, and technology. The principal emphasis is on conventional energy resources, but the report discusses possible future energy sources as well, including geothermal power. An atlas on North American energy resources includes a map of known and potential geothermal fields.

Hodgson, Susan F. A Geysers Album: Five Eras of Geothermal History. Sacramento: California Department of Conservation, Division of Oil, Gas, and Geothermal Resources, 1997. Brief report describes five periods in the geothermal history of California as experienced at the Geysers field: the wilderness era, the era of use by Native Americans, the age of tourism, a 1920’s electrical generation project, and the era of modern electrical generation.

U.S. Department of Energy. Office of Energy Efficiency and Renewable Energy. Geothermal Today: 2005 Geothermal Technologies Program Highlights. U.S. Department of Energy Report DOE/GO-102005-2189. Washington, D.C.: Government Printing Office, 2005. Describes the accomplishments and activities in geothermal energy production in the United States in the early twenty-first century.

Weaver, Kenneth F. “Geothermal Energy: The Power of Letting Off Steam.” National Geographic 152 (October, 1977): 566-579. A brief survey of geothermal energy resources, their utilization, and possible future impact on energy production. Includes diagrams of the geologic structure of principal types of geothermal heat sources and their geographic distribution.