Renewable energy resources include the resources which are regularly generated or created by natural processes or can be generated by processes such as farming. These include a range of different sources such as hydro power, solar power, wind power, geothermal power, tidal power, vegetable oil, and alcohol made form sugar cane and other vegetable products. Different sources of renewable energy present different advantages and disadvantages. However one common advantage of such sources is that they don't get depleted with with use. Also most of the renewable energy sources produce energy without creating environmental pollution in form of exhaust gases from burning of fuel. Burning of Alcohol produces much less pollution. However, use of vegetable oils as fuel can be as polluting as the non-renewable energy source. The biggest disadvantage for most of the sources is that technology for producing energy economically on a large scale is not available. Also while there is no depletion of these source of energy, there is limitation on the total rate of power that can be generated. Also this maximum rate is also fluctuates from time to time. For example solar power is available only during the day, and hydro-power availability fluctuates with availability of water for generation, which fluctuates heavily with seasonal variations.

The non-renewable energy resources primarily refer to the energy that is available form burning of fossil fuel such as coal and petrol. The two biggest disadvantages of this source are the limited stock of such fuel in the world, and pollution. Fossil fuel stocks have been created by earth's natural processes over millions of years. The rate at which we are now using these resources is very high, while the rate of creation of such new stocks is practically zero. In such condition the humanity is likely to run out of the stocks of non-renewable fossil fuel in foreseeable future. Also burning of fossil fuel creates environmental pollution which is likely to have very serious negative impact on the very existence of humanity.The biggest advantage of fossil fuel is availability of a very well developed technology for producing and using them.

At present, most of our energy comes from fossil fuels (coal, oil and natural gas). However, reserves are limited. Because demand for electricity is rising rapidly, fossil fuels will be exhausted in a relatively short time. Therefore, people must develop and use alternative energy sources.

An alternative energy source is nuclear power. Nuclear power can provide enough electricity for the needs of the world for hundreds of years, but it can be very dangerous. An alternative source of geothermal energy comes from deep within the earth. Scientists use heat to generate energy. However, this energy is only available in some parts of the world.

Sun, water and wind are alternative sources of energy. Wind rotating the windmill and moving the sailboat. It's a clean source and a lot of energy. Unfortunately, if the wind does not blow, there is no wind energy. As water moves from one place to another, it makes energy. However, people have to build dams to use this energy source. The dams cost a lot of money, so water is expensive too.

The sun releases large amounts of energy each day. This energy can be converted into electricity. Many countries use solar energy for their daily lives. Solar panels on the roof can generate enough energy to heat or cool the entire home. Solar energy is not only abundant and infinite but also clean and safe.

Despite some drawbacks, the potential of alternative energy sources is enormous. However, how to make full use of the energy resources is a question for researchers all over the world.