Coal and natural gas are nonrenewable sources of energy. Carbon dioxide, sulfur, nitrogen, mercury and other pollutants are released when coal is burned, and they are harmful for the environment and human health. Natural gas production also carries the risk of causing air and water pollution. Alternative sources of energy will be required in the future to sustain economic growth and ease demand and price pressures on fossil fuels. However, University of Michigan at Ann Arbor professor Barry Rabe, quoted by "Forbes" reporter Elisabeth Eaves, suggests that one energy source is unlikely to dominate in the future.
Solar power can harness the sun's energy for homes and businesses in a clean environmentally friendly way. Businesses can use solar and other forms of alternative energy to diversify their energy sources and reduce overall costs. According to the U.S. Department of Energy's National Renewable Energy Laboratory, common solar technologies include concentrating solar power, which harnesses solar energy for use in large power generating stations; photovoltaic technology that converts sunlight directly to electricity; and passive solar heating, which involves the design of buildings to make optimal use of natural sunlight.
As solar power technology matures in the future and production costs decline, solar power is likely to become a viable alternative to coal and natural gas in certain applications. It could also become an affordable source for electricity in emerging economies that do not have an abundant supply of fossil fuels.
Wind turbines, spread across hundreds of miles of open areas, can convert wind energy into mechanical power, which is then converted to electricity to power homes and businesses. Wind power requires open windy areas because the energy generated is proportional to the wind speed. According to the U.S. Energy Information Administration, wind energy was about 1.3 percent of total U.S. electricity generation in 2008, and the top five wind power producing states were Texas, Iowa, California, Minnesota and Washington.
Wind energy is a clean and emission-free source of energy. However, initial installation costs are high, people often complain about the noise and aesthetics, and the turbines are usually located far from densely populated areas where the electricity is most needed. The use of wind power to replace coal and natural gas is likely to be on a limited basis in the future because of the high initial installation costs and the intermittent nature of the energy source.
Bioenergy and geothermal energy are other future alternatives to coal and natural gas. Geothermal energy is produced from hot water and magma found below the earth's surface. Bioenergy is produced from organic matter or biomass, such as agricultural crop waste, animal and municipal waste, and aquatic plants.