Lester R. Brown
Chapter 10. Stabilizing Climate: Energy From the Earth
When we think of renewable energy, we typically think of those sources that derive directly or indirectly from the sun. But the earth itself is a source of heat energy (mostly from radioactivity deep within the earth), which gradually escapes either through conduction or through hot springs and geysers that bring internal heat to the earth’s surface. Geothermal energy is inexhaustible and will last as long as the earth itself.
Aside from being an ideal source for base load (continuous) power, geothermal energy is environmentally attractive for several reasons. Its carbon dioxide, sulfur dioxide, and nitrogen oxide emissions are negligible to non-existent. Water use for geothermal electric generation is 1 percent that of natural-gas-fired power plants. 52
The potential of geothermal energy is extraordinary. Japan alone has an estimated geothermal electric-generating capacity of 69,000 megawatts, enough to satisfy one third of its electricity needs. Among the countries rich in geothermal energy are those bordering the Pacific in the so-called Ring of Fire. These include (on the east) Chile, Peru, Ecuador, Colombia, all the Central American countries, Mexico, the western United States, and Canada and (on the west) Russia, China, South Korea, Japan, the Philippines, Indonesia, Australia, and New Zealand. Other geothermally rich countries include those along the Great Rift of Africa and the Eastern Mediterranean. Fortunately, many countries now have enough experience and engineering capacity to tap this vast resource. 53
Like solar energy, geothermal energy is used both to generate electricity and to directly heat buildings, greenhouses, and aquacultural ponds. It is also used as a source of heat for industrial processes. After Italy pioneered the use of geothermal energy to generate electricity in 1904, the practice spread to some 25 countries. The global capacity of 8,400 megawatts in 2003 represents a 44-percent growth over the 5,800 megawatts available in 1990. 54
Two countries—the United States with 2,000 megawatts and the Philippines with 1,900 megawatts—account for almost half of world generating capacity. In the Philippines, geothermal provides a world-leading 27 percent of the country’s electricity supply. California, the most populous state, gets 5 percent of its electricity from geothermal power plants. Most of the remaining geothermal power generation is concentrated in five countries: Italy, Mexico, Indonesia, Japan, and New Zealand. 55
The direct use of geothermal heat for various heating purposes worldwide is even larger, equivalent to 12,000 megawatts of electricity generation. Its use in heat pumps, which extract and concentrate heat from warm water for various uses, is the largest single use. More than 30 countries tap geothermal energy for heating. 56
Iceland and France are the leaders. In Iceland, 93 percent of the country’s homes are heated with geothermal energy, saving over $100 million per year in avoided oil imports. Geothermal energy accounts for more than one third of Iceland’s total energy use. Following the two oil price hikes in the 1970s, some 70 geothermal heating facilities were constructed in France, providing both heat and hot water for an estimated 200,000 residences. In the United States, individual homes are supplied directly with geothermal heat in Reno, Nevada, and in Klamath Falls, Oregon. Other countries that have extensive geothermally based district-heating systems include China, Japan, and Turkey. 57
Geothermal energy is an ideal source of heat for greenhouses, particularly in northern climes. Russia, Hungary, Iceland, and the United States all use geothermally heated greenhouses to produce fresh vegetables in winter. With rising oil prices boosting fresh produce transport costs, this option will likely become more popular in the years ahead. 58
Some 16 countries use geothermal energy for aquaculture. Among these are China, Israel, and the United States. In California, for example, 15 fish farms produce tilapia, striped bass, and catfish with warm water from underground. This warmer water enables fish to grow without interruption during the winter and to mature more quickly. Collectively these California farms produce 4.5 million kilograms of fish per year. 59
The number of countries turning to geothermal energy both for electricity and for direct use is increasing rapidly. So, too, is the range of uses. Once the value of geothermal energy is discovered, its use is often quickly diversified. Romania, for example, uses its geothermal energy for district heating, for greenhouses, and to supply hot water for homes and factories. With heat pumps, the earth can serve as both a heat source and a sink to provide heating in winter and cooling in summer. 60
Geothermal energy is widely used for bathing and swimming. Japan, for example, has 2,800 spas, 5,500 public bathhouses, and 15,600 hotels and inns that use hot geothermal water. Iceland uses geothermal energy to heat some 100 public swimming pools, most of them year-round open-air pools. Hungary heats 1,200 swimming pools with geothermal energy. 61
Indonesia, with more than 222 million people, could easily get all of its electricity from geothermal energy. Situated on the western edge of the Pacific, with 500 volcanoes, 128 of them active, Indonesia has a master plan for 11 geothermal power plants with a generation capacity of just over 300 megawatts each—a total of 3,400 megawatts. This plan was derailed by the Asian financial crisis of 1997, but supporters are now attempting to revive it. With its oil production falling, Indonesia needs to quickly develop alternative sources of energy. Unlike investments in oil, those in geothermal energy are tapping an energy source that can last forever. 62
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