GeoThermal

Geothermal energy is energy obtained by tapping the heat of the earth itself, both from miles deep into the Earth's crust in volcanically active locations of the globe or from shallow depths, as in geothermal heat pumps in most locations of the planet. It is expensive to build a power station but operating costs are low resulting in low energy costs for suitable sites. Ultimately, this energy derives from heat in the Earth's core.
Three types of power plants are used to generate power from geothermal energy:
Dry steam -Dry steam plants take steam out of fractures in the ground and use it to directly drive a turbine that spins a generator.
Flash-Flash plants take hot water, usually at temperatures over 200 °C, out of the ground, and allows it to boil as it rises to the surface then separates the steam phase in steam/water separators and then runs the steam through a turbine.
 Such geothermal power sources exist in certain geologically unstable parts of the world such as Chile, Iceland, New Zealand, and the United States The two most prominent areas for this in the United States are in the Yellowstone basin and in northern California. Iceland produced 170 MW geothermal power and heated 86% of all houses in the year 2000 through geothermal energy. Some 8000 MW of capacity is operational in total.

Hydroelectric

Hydroelectric is a form of renewable energy that is not really growing in popularity. Hydro has been an established form of energy that is proven to work at a reasonably high production rate. Hydro power has been used since ancient times to grind flour and perform other tasks. In the mid-1770s, a French engineer Bernard Forest de Bélidor published Architecture Hydraulique which described vertical- and horizontal-axis hydraulic machines. By the late 19th century, the electrical generator was developed and could now be coupled with hydraulics. The growing demand for the Industrial Revolution would drive development as well.. The major down fall for using hydro opposed to other forms of energy is that it requires a large body of water or a moving water source. The danger or hazard of hydro power exists if the dam were to give way. Most hydroelectric power comes from the potential energy of dammed water driving a water turbine and generator.

http://en.wikipedia.org/wiki/Hydroelectricity

Wind Energy

Wind energy is a form of renewable energy that is becoming more popular everyday. Wind is a byproduct of solar energy; the uneven heating of the air over land and water creates wind as warm air rises and cool air rushes in to take its place. It has been harnessed as energy for thousands of years in the form of windmills, but more recently wind power has been able to be transformed into raw power.


For the first time wind power has been viewed as a possible renewable source of electricity. In recent years modern "wind farms" have been constructed with large numbers of turbines that generate electricity when rotated by the wind. As of 2009, wind power usage was growing in the United States at the rate of 30 percent per year. However, some people oppose the construction of large wind farms because they believe such farms are dangerous to flying birds and mar scenic views.

A proposed offshore wind farm off of Cape Cod, Massachusetts, has run into opposition for these reasons. As of 2009, the United States led the world in wind power, in terms of megawatts of power produced. Within the United States, Texas is by far the largest producer of wind energy, with 9,410 megawatts of capacity as of 2009.

"Renewable Energy." Current Issues: Macmillian Social Science Library. Detroit: Gale, 2010. Gale Opposing Viewpoints In Context. Web. 8 Nov. 2010.

Locations

As wind energy begins to take flight, scientists and engineers continue to discover new ideas and possible places that wind turbines can be placed.These possible areas include:

Fields and on turbine farms

At sea or in Oceans

On highways and expressways

And in residential applications

Revenue?

Wind turbines can be an expense investment. When investors look to install hundreds of them they often want to know how long it will take to make there money back. The general rule of thumb is that the larger the rotor sweep (or area blades span) the more energy will be produced. The larger blades can provide more torque to turn a larger generator. Wind energy is currently the best investment for making money back the chart at the left shows investment revenue for many electricity producing methods.

Solar Energy

Solar energy is also a form of renewable energy that has became more popular over the past few years. Solar energy captures the sunlight and converts it into electricity. Solar products are also being incorporated in many of our house hold products. These products include:

• outdoor solar lights
• calculators
• cell phone chargers
• car chargers

Advantages

• Inexhaustible fuel source
• No pollution
• Often an excellent supplement to other renewable sources
• Versatile--is used for powering items as diverse as solar cars and satellites

Disadvantages

• Very diffuse source means low energy production--large numbers of solar panels (and thus large land areas) are required to produce useful amounts of heat or electricity
• Only areas of the world with lots of sunlight are suitable for solar power generation

 

http://library.thinkquest.org/20331/types/solar/advant.html