4.4. Alternative energy

Before you read think over the following questions

- Why do a lot of think tanks today are in search of alternative kinds of energy?

- What resourses are considered by the scientists as such kinds of energy?

- Is it possible that these alternative sourses of energy will appear to be threatening to the enveronment?

Fossil fuels are hydrocarbons, primarily coal, petroleum or natural gas, formed from the remains of dead plants and animals. The theory that hydrocarbons were formed from these remains was first introduced by Mikhail Lomonosov in 1757. The utilization of fossil fuels has enabled large-scale industrial development and largely supplanted water-driven mills, as well as the combustion of wood or peat for heat. When generating electricity, energy from the combustion of fossil fuels is often used to power a turbine.

Yet the burning of fossil fuels by humans is the largest source of emissions of carbon dioxide, which is one of the greenhouse gases that contribute to global warming. With global modernization in the 20th and 21st centuries, the thirst for energy from fossil fuels, especially gasoline derived from oil, has become one of the causes of major regional and global conflicts. A global movement toward the generation of renewable energy is therefore underway to help meet the increased global energy needs.

For many decades humanity has been striving to find various renewable power sources so that to use them in place of fossil fuels and uranium. Nuclear fusion devices are believed by some to be the best long-term option, because their primary energy source would be deuterium, abundant in ordinary water. Other technologies include solar energy, wind power, tidal power, wave power, hydroelectric power, and geothermal energy. The amount of energy in such renewable and virtually pollution-free sources is large in relation to world energy needs, yet at present only a small portion of it can be converted to electric power at reasonable cost.

Solar energy

Radiation from the Sun can produce heat, generate electricity, or cause chemical reactions. Solar energy is inexhaustible and nonpolluting, but converting solar radiation to electricity is not yet commercially competitive. Solar batteries play an important part in space satellites. Solar heating systems can supply heat and hot water for domestic use; heat collected in special plates on the roof of a house is stored in rocks or water held in a large container. Such systems, however, usually require a conventional heater to supplement them.

Wind power

Like waterwheels, windmills were among the original prime movers that replaced human beings as a source of power. Their most important traditional use was for grinding grain, though in certain areas their use in land drainage and water pumping was equally important. Windmill use became increasingly widespread in Europe (particularly the Netherlands) from the 12th century to the early 19th century, but thereafter slowly declined. Interest in windmills for generating electric power revived in the 1970s. Though wind is irregular and spread out, it contains tremendous amounts of energy. Sophisticated wind turbines have been developed to convert this energy to electric power.

Hydroelectric power

Electricity can also be produced by generators driven by water turbines that convert the energy in falling or fast-flowing water to mechanical energy. The advantages of hydroelectric power over such other sources as fossil fuels and nuclear energy are that it is continually renewable and produces no pollution. Norway, Sweden, Canada, and Switzerland rely heavily on hydroelectricity because they have industrialized areas close to mountainous regions with heavy rainfall. The U.S., Russia, China, India, and Brazil get a much smaller proportion of their electric power from hydroelectric generation.

Tidal-electric power is obtained by utilizing the recurring rise and fall of coastal waters. Large amounts of electric power could be developed in the world's coastal regions having tides of sufficient range, although even if fully developed this would amount to only a small percentage of the world's potential water power.

The term geothermal energy stands for power obtained by using heat from the Earth's interior. Most geothermal resources are in regions of active volcanism. Hot springs, geysers and pools of boiling mud are the most easily exploited sources. The ancient Romans used hot springs to heat baths and homes, and similar uses are still found in Iceland, Turkey, and Japan. Geothermal energy's greatest potential lies in the generation of electricity. It was first used to produce electric power in Italy in 1904. Today geothermal power plants are in operation in New Zealand, Japan, Iceland, Mexico, the U.S., and elsewhere.