World is advancing rapidly and consume more energy than ever with the development of technologies. Green energy suggests the idea  of using energy such that it meets the needs of the present without compromising the ability of future generations to meet their own needs. In addition green energy ( Also known as renewable energy) provides lower carbon emissions and create less pollution.

Green energy is environmentally friendly and non-polluting, such as geothermal, wind, solar, and hydro. Sometimes nuclear power is also considered a green energy source. Green energy sources are often considered “green” because they are perceived to Green energy is commonly thought of in the context of electricity generation.

Geothermal

Geothermal is a Greek word where geo, meaning earth, and thermos, meaning heat. In geothermal energy power extracted from heat stored in the earth to produce electricity. In 2007 about 10 gigawats power has been produced through geothermal technology.

Geothermal power is reliable, sustainable, and environmentally friendly, but it’s costly. Drilling and exploration for deep resources costs tens of millions of dollars, and success is not guaranteed. Another obstacle is historically it has been limited to areas near tectonic plate boundaries. However recent technological advances have dramatically expanded the range and size of viable resources, especially for applications such as home heating, opening a potential for widespread exploitation.

Wind power

A widely used natural source to generate power or electricity. This is the technology to convert wind energy into a useful form of energy, such as using wind turbines to make electricity, wind mills for mechanical power, wind pumps for pumping water or drainage, or sails to propel ships.

Most of the European countries generate electricity through wind power. Denmark, Spain, Portugal, Germany, Ireland most depend on wind power to generate electricity. Now there are about eighty countries around the world are using wind power on a commercial basis. At the end of 2009 wind power generates 157.9 gigawatts (GW)  electricity. which is about 1.5% of worldwide electricity usage.

Solar Power

Using sunlight to produce electricity is one of the oldest method in green energy. Solar power is the conversion of sunlight to electricity. Using photovoltaics electricity can be produced  by using the Sunlight directly. In indirect way sun’s energy help to boil water which is then used to provide power, and technologies such as the Stirling engine dishes which use a Stirling cycle engine to power a generator.

Main problem solar power plants can face high installation costs, although this has been decreasing due to the learning curve. Developing countries have started to build solar power plants, replacing other sources of energy generation.

Hydro power

China is the pioneer of hydroelectricity. China produces most of their electricity through hydro power and has the world largest hydro electricity plant. Hydroelectricity is electricity generated by hydro power, i.e., the production of electrical power through the use of the gravitational force of falling or flowing water. It is the most widely used form of renewable energy.