Energy is the ability of a physical system to do work on other physical systems. Our primary energy supply consists of fossil fuels such as coal, oil and natural gases used to heat homes, to produce electricity and to fuel our automobiles and means of transport. Fossil fuels formed from plants and animals lived hundreds of millions of years ago are buried under the Earth’s surface where their remains are transformed into the combustible materials that we use for fuel. We are also experiencing nuclear energy from the splitting of atoms but it is not likely to be a major source of energy because of public pressure and the dangers associated. Alternative energy means energy produced from sources different from our primary energy supply.
The interest in this field comes from the negative effects of pollution and global warming. Wind and hydroelectric power have been used for generations together with solar energy, but now they are making progress: modern windmills have become very efficient, solar energy is having impact on home energy needs, solar panels can produce an important part of the total renewable energy sources for the future.
Renewable energy sources help reduce global carbon dioxide emissions and add flexibility to the energy resource need, decreasing our dependence on fossil fuels. Sun, wind and water are perfect energy sources for they are non-polluting, renewable and efficient. Alternative energy sources can be used on a small scale by individual homeowners and businesses. They can also be used for large-scale operations connected to a municipality's existing electric plant.
