The energy used today comes from fossil fuels, which are a limited, non-renewable resource that will eventually be exhausted. Alternative energy sources such as solar, hydroelectric, geothermal and wind can be used to conserve the planet's limited natural resources. Alternative energy is the use of another energy without burning fossil fuels or breaking down into 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 towns. Geothermal energy can be used to heat buildings or water and to power turbines to produce electricity. Wind energy can be used to pump water and generate electricity. Solar energy is one of the most resourceful alternative energy sources. It is the most important unconventional energy source because it does not pollute the earth. “One reason for this is that the total energy we receive each year from the sun is about 35,000 times greater than 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 things, but most of it is used for heating, cooling, transportation, and power generation. When the sun's rays are transformed into electricity, we speak of photovoltaic energy. It's a simple way to get electricity. Photovoltaic panels can be installed on the roof of a house to provide electricity or used in remote locations where there is no electricity from other sources. Solar energy also powers cars without using gasoline made from fossil fuels. Solar-powered vehicles (SPV), 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 engine. They use an array of photovoltaic (PV) solar cells (or modules made of cells) that convert sunlight into electricity. The electricity either goes directly to an electric motor powering the vehicle or to a special storage battery. The photovoltaic array can be built (integrated) onto the vehicle body itself, or attached to a building or vehicle shelter to charge an electric vehicle (EV) battery when parked. (Green nature) Then, "Hydroelectric power is the largest source of renewable energy...... middle of paper......, 000 light bulbs that consume 100 watts (Energy story) Even though You can only use wind turbines in fairly windy regions, they are still an efficient way to produce without burning fossil fuels. Fortunately, there are many ways of alternative energy sources to conserve Earth's limited natural resources. Solar, hydroelectric, wind and geothermal are the alternative energy sources that will be used in the film, so that consumers will not rely as much on the Earth's natural resources as they currently do. As the world continues to grow and needs energy, applied science will discover more alternative energy sources for use in the future. Wind Energy, April 15, 2005 www.energyquest.ca.gov/story/chapter16.htmlGreen Nature. Solar-powered vehicles April 25, 2005=82