There are many reasons we are looking towards alternative energy sources. With many countries, signing the Kyoto Treaty, efforts to reduce pollutants and greenhouse gases are a primary focus in today's culture. Alternative, or renewable energy, sources show significant promise in helping to reduce the amount of toxins that are by-products of energy use. Not only do they protect against harmful by-products, but using alternative energy helps to preserve many of the natural resources that we currently use as sources of energy.
To understand how alternative energy use can help preserve the delicate ecological balance of the planet, and help us conserve the non-renewable energy sources like fossil fuels, it is important to know what types of alternative energy is out there.
Wind energy harnesses the power of the wind to propel the blades of wind turbines. The rotation of turbine blades is converted into electrical current by means of an electrical generator. In the older windmills, wind energy was used to turn mechanical machinery to do physical work, like crushing grain or pumping water.Wind towers are usually built together on wind farms. Now, electrical currents are harnessed by large scale wind farms that are used by national electrical grids as well as small individual turbines used for providing electricity to isolated locations or individual homes. In 2005, worldwide capacity of wind-powered generators was 58,982 megawatts, their production making up less than 1 of world-wide electricity use.
Solar energy is used commonly for heating, cooking, the production of electricity, and even in the desalination of seawater. solar power works by trapping the sun's rays into solar cells where this sunlight is then converted into electricity. Additionally, solar power uses sunlight that hits solar thermal panels to convert sunlight to heat water or air. Other methods include using sunlight that hits parabolic mirrors to heat water (producing steam), or simply opening a rooms blinds or window shades to allow entering sunlight to passively heat a room.
Literally, geothermal means, "earth heat." Geothermal energy harnesses the heat energy present underneath the Earth. Hot rocks under the ground heat water to produce steam. When holes are drilled in the region, the steam that shoots up is purified and is used to drive turbines, which power electric generators.
Hydroelectric power comes from the potential energy of dammed water driving a water turbine and generator. Another variation is to make use of water's kinetic energy or undammed sources such as tidal power. Hydro power works by harnessing the gravitational descent of a river that is compressed from a long run to a single location with a dam or a flume. This creates a location where concentrated pressure and flow of water can be used to turn turbines or water wheels. These can then drive an electric generator. This can be compared to past days when a water wheel would drive a mill. Electric generators powered by hydro power can be run backwards as a motor to pump water back up for later use.