Harnessing the heat from deep inside the earth is one of the world’s oldest sources of energy. The Romans bathed in spas built around natural hot springs, and Native Americans cooked food and heated their homes with geothermal energy. Now this power source is being tapped for both heat and electricity.
Geothermal energy is used mostly in volcanic regions, where hot magma pools close to the earth’s surface. There are three ways to use geothermal energy. The first is direct usage: heating water by running pipelines close to hot spots in the earth. The second is to tap into underground steam vents; the steam is used to turn the turbines in a power plant. The third is to pump water from an outside source into the ground, where superheated rocks boil the water to generate steam. The steam is then sent to a power plant to turn turbines.
There are many advantages to using geothermal energy. The most important is that it is a clean energy source. And like many other sources of renewable energy, the initial construction of a geothermal plant is very expensive, but the cost is quickly recouped because the “fuel” is free. Another major advantage for a fossil-fuel-free economy is that, if the plant is properly sited in an area with a constant source of geothermal heat and the water is pumped in from an outside source, the plant can provide uninterrupted and reliable power to the grid.
In addition to the many advantages, however, there are several drawbacks. The major disadvantage is that its usage is highly limited – geothermal plants mainly have practical application in regions with a lot of underground volcanic activity. It is possible to utilize geothermal energy in other regions, but the heat can only be accessed by drilling deep into the earth; such sources may also eventually run out of heat. And if a geothermal plant taps a steam vent deep in the earth without replenishing it with more water, then it becomes a nonrenewable resource; the steam will eventually be used up.
The use of geothermal energy is growing worldwide. Iceland currently uses it for 17% of its municipal power generation and 87% of its hot water needs. Hot water is heated in large facilities rather than in boilers in individual homes and businesses, and hot and cold water is piped into buildings through separate systems. There are five geothermal plants in Iceland, one of which has been creatively designed to pump the used heated sea water into a mineral spa called the Blue Lagoon. California has a number of volcanic hot spots and currently generates about half of the world’s geothermal electricity. Many other countries are currently expanding their use of geothermal energy as well; it is a cost-effective source of electricity on the west coast of Africa and is now being used on every continent.
Wikipedia, the free encyclopedia (articles on Geothermal power and Blue Lagoon)
“An Introduction to Geothermal Energy,” The University of Prince Edward Island
“ What Are the Advantages and Disadvantages of Geothermal Energy?” Geothermal-Heat-Pumps.com