The energy used today comes from fossil fuels, which are a limited non-renewable resource that will eventually be exhausted. To preserve the planet's limited natural resources, alternative energy sources such as solar, hydroelectric, geothermal and wind energy can be used. Alternative energy is the use of another energy without the burning of fossil fuels and the fragmentation of atoms. Solar energy can be used to run cars and provide electricity to homes and businesses. Hydroelectric power can be used to provide electricity to small cities and towns. Geothermal energy can be used to heat buildings or water and to power turbines to produce energy. Wind energy can be used to pump water and generate electricity. Solar energy is one of the most ingenious alternative energy sources. It is the most important of non-conventional energy sources, because it does not pollute the earth. “One reason is that the total energy we receive each year from the sun is about 35,000 times the total energy used by humans.” (Alternative Energy Sources) Solar energy can be converted directly or indirectly into alternative forms of energy. People use solar energy for many purposes, but most are used for heating, cooling, transportation, and electricity generation. When the sun's rays are transformed into electrical energy, it is called photovoltaic energy. This is an easy way to get electricity. Photovoltaic panels can be placed on the roof of a house to provide electricity, or they can be used in remote locations where there is no electricity from other sources. Solar energy also powers cars without the use of gasoline, which is produced from fossil fuel oil. Solar-powered vehicles (SPVs), such as cars, boats, bicycles, and even airplanes, use solar energy to directly power an electric motor, and/or use solar energy to charge a battery that powers the motor. They use an array of photovoltaic (PV) solar cells (or modules made up of cells) that convert sunlight into electricity. The electricity goes directly to the electric motor that powers the vehicle or to a special storage battery. The photovoltaic array can be built (integrated) onto the body of the vehicle itself or attached to a building or carport to charge the battery of an electric vehicle (EV) when it is parked. (Green Nature) Then, “Hydroelectric power is the largest renewable energy source…… half of paper……,000 light bulbs consuming 100 watts (Energy Story) Although you can only use windmills in in areas enough suckers are still an effective way to produce without burning fossil fuels. Fortunately, there are many ways to conserve the earth's limited natural resources through alternative energy sources. Solar, hydroelectric, wind and geothermal energies are the alternative energy sources that will be used in the service, so that consumers no longer rely on the earth's natural resources as they do now. As the world continues to grow and need energy, applied science will discover more alternative energy sources for use in the future. Works Cited Energy Story. Wind Energy, April 15, 2005 www.energyquest.ca.gov/story/chapter16.htmlGreen Nature. Solar-powered vehicles 25 April 2005 greennature.com/article101.htmlThe World Bank Group. Geothermal Energy, April 19, 2005 www.worldbank.org/html/fpd/energy/geothermal/Tran P.. Alternative Energy Sources, April 19, 2005 www.cc.utah.edu/~ptt25660/tran.htmlUnion of Concerned Scientists. How hydropower works, April 25=82