Alternative green energy might be used to describe any unconventional system that is used to generate electric power or heating. There are two distinguishable types of alternative green energy. One is defined as renewable sources of energy and includes, wind power, solar power and various water power options. The second and most controversial types are described as earth-based sources of energy. This second type includes geothermal power and biofuels.

The alternative green energy that uses windmill technology is called wind power. The force of the wind against the blades of a mill is powerful enough to turn electricity turbines. Windmills do have the disadvantage of being unsightly when they are sited with enough density across open terrain. People living close to them have also complained of their noise. Despite these drawbacks, wind power is still classified as a very efficient green energy.

Solar energy is a popular alternative green energy system. The energy of the sun could potentially be harnessed to power every home on the planet. Solar power is used to heat water that is fed into pipes for heating and hot water supply. Solar heated water can be transformed into hydrogen gas which is used for driving turbines. Solar energy can also be converted into direct electricity with photovoltaic solar panels. It is often argued that the production of solar cells is expensive and creates its’ own environmental problems.

Hydroelectric power is the alternative energy system that has seen the greatest degree of implementation worldwide. This is because it is relatively cheap to install and many countries have the resources needed to operate it. Energy is generated through the action of moving water through turbines. The main criticisms of hydro power are that the dams necessary to create them often disrupt natural waterways and fertile lands are often flooded to create the lakes required to implement this technology, thus displacing local people.

Geothermal power seeks to generate electricity by tapping heat locked deep down below the earth’s surface. Rock that is heated by magma deep inside the earth is the source of energy for geothermal power. Water is pumped down through boreholes to acess these extremely high temperatures below ground and then forced back out again to run steam generators.

The high pressure steam produced using geothermal power is used to run power plants. This alternative green energy system is thought to have unlimited potential because of the untapped heat source available deep within the earth. The problems that still have to be overcome are exceedingly high drilling costs and uncertainties about its possibility to cause earthquakes.

Oil rich plants like rapeseed can be processed into diesel for powering engines. Likewise, plants with a high sugar content such as sugar cane can be distilled into ethanol to run cars. The alternative green energy that makes use of such fuels is called biofuel. Although biofuels are completely renewable they have come under heavy criticism because of the amount of agricultural land that is needed to grow them. Critics further argue that biofuels still produce levels of carbon emissions associated with global warming. However, supporters of biofuels claim that biofuels are carbon neutral because growing crops generate carbon and at the same time, consume carbon dioxide.