At the beginning of the twentieth century the world has suffered from the exploitation of natural resources and air pollution and soil degradation. Oil, for example, has been a source of energy, and extracted continuously so that their wells have begun to run low, less than 100 years after the beginning of their effective use. Coal is a resource even older, is also considered esgotável. Nuclear power, just as is the warning about the danger of radioactive waste. The use of traditional sources traces its history to the decline, not only for his character, but that is a threat to the environment.

We call an alternative source of energy in ecology is to gain a growing area, the sources that call the alternative, which does not affect the nature, and are renewable, and is why they are perennials, there are several types of sources for example, is renewable energy, including solar energy is the solar panels, photovoltaic cells and wind is the wind turbine and a windmill, water and hydro power is the wheel, water turbine and biomass is a matter of plant origin.

Brazil has shown in international fora, that it intends to improve the use of renewable energy and diversify sources of power generation, with this commitment, it reduces the risk of further water shortages, which often leads to crisis situations and rationing.

Many see the generation of renewable energy as an isolated initiative, unable to meet the demand of a large continental country. With the use of alternative energy is not immediately necessary to abandon traditional resources. Already in Germany, for example, showed that the use of renewable sources can be useful to the state, and for the people and the environment. Germany accounts for around one third of all wind power installed worldwide. This represents half of the energy generated in the entire investment Europa.com German deployment allows the use of fuel from plants, or biomass. It is virtually inexhaustible source of solar energy that can be used to produce electricity through solar panels and photovoltaic cells. Countries that the amount of sunlight is abundant throughout the year, which encourage the use of resources. There are two main issues in the use of passive and active solar energy.

The active ingredient is based on the method of transforming sunlight into other forms of energy: heat or electricity, while the passive is used to heat buildings or buildings through design and construction strategies. This application is most common in the cold in Europe, where demand for heating options. Photovoltaic panels, but the most promising source of renewable energy, because their main advantage is the almost total absence of pollution. The main limitation of photovoltaic devices is their low income level, because the other drawback is the cost of producing groups that are high due to the limited availability of semiconductor materials.