Nonrenewable energy sources represent about 90% of the energy used today. These sources are being depleted. Since they are known to have an effect on air quality, causing human and environmental health problems, a greater emphasis is being placed on renewable energy sources as the new frontier for energy. Renewable energy sources consist of solar, hydro, biomass, geothermal and ocean. These sources of energy will never become exhausted and are environmentally friendly, since they do not contribute to greenhouse effects or global warming.



Solar energy is the most readily available renewable energy source. We have used the sun's energy for billions of years. Prehistoric men magnified its strength to start fires. Today, solar panels absorb energy from the sun to produce heat for cooking and heating, as well as, for electrical needs. This heat absorption is stored for later use and is an indirect conversion of energy. Currently, electric companies are trying to use photovoltaic technologies to convert solar energy directly to electricity.

Hydro energy draws on energy produced by flowing water. Waves are the result of wind interacting with the surface of the sea. This interaction produces a transfer of energy that can be extracted for power generation using turbine generators. Although hydropower is non-polluting, it can do environmental harm. Hydroelectric generating stations can change the flow of the sea and in doing so harm plants and animals.

Wind energy, or kinetic energy, is drawn from the movement of air. It has been used for hundreds of years for sailing, grinding grain and irrigation. Today, wind turbines transform energy from wind to mechanical energy or to charge batteries. The wind machines, or wind turbines collect the kinetic energy by capturing the wind in its blades. The blades then turn an electric generator to produce energy. Unfortunately, wind energy collection is unavailable on windless days. Even though it is a clean form of energy it has had a negative effect on the wild bird population and some consider the giant wind turbine machines not attractive looking.

Biomass energy comes from wood, garbage, food crops, manure, grasses and plants, agricultural and forestry waste and residue. It basically comes from refuse. This renewable energy is also not new. It was used over 100 years ago in the form of wood burning, which supplied 90% of energy needs at that time. When biomass is burned, it produces heat or electricity. It can also be converted to methane gas, which is the main ingredient of natural gas. It represents 3% of the energy in the United States. Although biomass can pollute the air and releases a greenhouse gas, it is not as pollutant as fossil fuels.

Geothermal energy is basically the Earth's heat. It is drawn from hot dry rocks, magma, hot water springs and hot geysers. These are found inside the Earth's underground. Some are found deep in the earth's surface and others are found closer to the surface. Today, this type of energy is used to heat water in swimming pools and spas, as well as, to warm buildings like greenhouses. It can also be used to produce electricity through the use of a geothermal power plant. In these plants the hot water travels through turbines, which are connected to a generator.

Ocean Energy is obtained from ocean waves or temperature differences in water. Wave energy is the kinetic energy from the movement of water. Tidal energy entails trapping tidal waves in reservoirs behind dams. Ocean Thermal Energy Conversion uses the differences in water temperatures from the surface water to deeper down depths of water as an energy source. In order for this to work there must be a temperature difference of 38 degrees Fahrenheit.

As you can see, there are various renewable energy sources available to us as an alternative to fossil fuels. There are many advantages to them among the most popular being that they will not deplete in supply, meaning they will be around forever. Renewable energy sources are not new. They have been utilized in some way for many years. Unfortunately, low fossil fuel prices have stunted renewable energy's popularity and growth in the United States. But an increasing awareness of human and environmental concerns, as well as, a need to find non-exhaustible energy sources, will keep it as a mainstay for the future.