An alternative source of energy in the nature of matter and processes that allow a human to obtain the energy necessary for existence.

The main direction of alternative energy is the search for and use of alternative (non-traditional) energy sources. An alternative energy source is a renewable resource, it replaces traditional energy sources that operate on oil, natural gas and coal, which, when burned, release carbon dioxide into the atmosphere, which contributes to the growth of the greenhouse effect and global warming. The reason for searching for alternative energy sources is the need to get it from the energy of renewable or almost inexhaustible natural resources and phenomena.

Alternative energy includes a number of promising ways of generating energy from available renewable resources and natural phenomena (wind, solar rays, moving water streams, geothermal waters and others). Additional advantages of renewable energy sources are absence of negative influence on the environment and human health, economy.