The 7 Alternative Renewable Sources

Renewable energy is energy collected from natural elements -- such as the sun, wind, water and plants -- which produces clean energy. Since renewable energy is naturally occurring, it is safe for the environment. Many countries around the world are interested in finding ways to develop and rely on renewable energy sources and technologies that bring down the cost of utilities, as well as decrease the usage of nonrenewable energies that are harmful to the environment.

Biomass

• Biomass refers to plants and other organic matter that are used as alternative sources of energy. Certain types of biomass have the ability to produce power and fuels. Biopower technologies use biomass resources, such as wood, to create heat and electricity. Biofuels are liquid fuels that are made out of biomass matter and used primarily for transportation. For example, ethanol is an alcohol that comes from corn that is used in gasoline.

Geothermal

• Geothermal technologies use the heat energy from the Earth to generate electricity. Environmental scientists and engineers can extract hot water, rock and molten rock from deep beneath the Earth's surface to harvest the heat they naturally emit. In turn, the heat is used to heat and cool homes and buildings. Geothermal technology allows the geothermal resources to be tapped to maintain a constant flow of energy and electricity.

Hydrogen

• According to the U.S. Department of Energy, hydrogen is the most plentiful element on Earth, but does not occur naturally. Therefore, for hydrogen to be used to produce electricity it must be extracted from a compound that contains hydrogen. Hydrogen fuel acts similarly to the function of a battery. It carries energy from one element to another, but does not produce energy by itself. Still, hydrogen is used in renewable technologies for storing or delivering energy.

Hydropower

• Hydropower is an alternative renewable energy source that uses flowing water to generate electricity. The amount of electricity that is generated from hydropower technology depends on the scale size. Large-scale hydropower plants produce more electricity than microhydropower plants. Large-scale hydropower plants use dams at reservoirs to store river water. During the hydropower process, water from the reservoir is released and begins to flow. The flowing power produces electricity that is collected and converted into energy.

Ocean

• The ocean is an all-natural collector of thermal energy from the sun, as well as a producer of mechanical energy through tides and waves. Tide and wave energy technology systems have been designed to collect energy that is produced through the natural motions of the ocean. Tidal turbines, for instance, act as underwater wind farms that collect energy brought in through the ocean's tides.

Solar

• Solar energy is collected from the sun's light and heat. With solar energy technology, sunlight is reflected off of mirrored surfaces and collected by receivers that store the light and heat and convert it into electricity to generate power in homes and buildings. A variety of solar energy technologies exist, including solar panels, dishes and cells.

Wind

• Wind produces energy through its movement. Wind turbines, which look like giant fans, are the most common form of wind energy technology. As the wind blows, it spins the turbine blades that create energy, which converts into electricity. Wind is often used for powering water pumps, batteries and for farm equipment, such as grain grinders.