Alternative energy sources are created from sources that do not consume natural resources and do not harm the environment. They are alternatives to fossil fuels, nuclear energy and hydropower to large scale, which are non-renewable sources of energy and also have various harmful effects on the environment. However, there is no commercially viable alternative sources of energy as the same use of the petroleum products, which along with coal and oil are the main types of fossil fuels. The first of all the alternative energy sources that usually comes to mind is the solar energy, which is created from several different procedures that ensure they harness the energy coming from the Sun. The main method used to convert sunlight into electricity using photovoltaic cells, which are arranged in solar panels, in such a way that the maximum amount of sunlight is absorbed and converted into electricity. In the Today, the biggest problem with solar power is cost, since cells and solar panels can be very costly. Another alternative energy source is wind energy, which uses large wind turbines to transform into wind energy.

Many of these turbines can be placed where the wind is plentiful, and these wind farms can be connected to a mains supply which contribute with electricity. A windmill can also be used to take advantage of wind power, but instead of converting wind into electricity, a windmill converts wind directly into mechanical movement to do the work required. Some alternative sources of energy are terrestrial, such as tidal power, geothermal energy and biomass source. Geothermal energy is obtained from sources of heat within the Earth, such as natural geysers, and it converts this heat into electricity. The use of the force of waves in the ocean and other bodies of water on the planet that is known as tidal power or tidal power. Finally, biomass energy is obtained from organic matter that comes from plants and animals, and is more commonly known as renewable energy source, since it creates a product residue. All these alternative energy sources should be investigated to a large extent if any of them will be used to replace fossil fuels as sources of primary energy in the world.