Geothermal energy is harvested from inside the Earth's crust. There are several different geo-thermal technologies. These include Geo-Thermal Electric, Direct Application and Geo-Thermal heat Exchange.

Geo-Thermal electric power plants are built where high temperature resources are available near the surface. The power plant created steam from cool water pumped into the ground and uses the steam to turn electric turbines.

Direct Application geo-thermal applies to lower temperature (<300°F) resources and are typically used in district heating, greenhouses and fisheries.

Geo-thermal heat exchange or geothermal heat pump.ground source heat pump is used for central heating/cooling systems that pump heat into buildings from the ground. This is done by running a fluid through a series of underground coils that is then pumped through a heat exchanger connected to the HVAC system. Thus reducing the load on conventioanal heat sources such as Natural Gas, Heating Oil and Coal. A large portion of the Earth's surface maintains a nearly constant temprature between 50°-60°F. This geo-thermal heat exchange is one of the most energy efficient and simple technologies on the market today.

Hydroelectricity is produced by the use of moving water, where power is generated from the
gravitational force of falling or flowing water. The amount of energy produced is dependent
on water pressure and differences in water level, therefore man made dams are constructed to
store and reserve water, which is then used as potential energy or fuel for power generation.
Power stations that contain turbines and generators are built on the downstream side of the dam.
Electrical power is generated within the power station as a result of rushing water spinning the
turbine at great speeds. The turbine is connected to a generator, which converts moving water
into electricity by inducing a current in a magnetic coil. Then once the electricity is produced it
is transported along transmission lines to an electrical utility company.

There are several pros to the using of hydroelectricity. A major advantage of using
hydroelectricity is that it is renewable and cheap. The major cost of generating hydroelectricity
is the cost of the building and maintaining the dams and power stations. There are no fossil
fuels used in the production of electricity, therefore no pollutants or wastes are released into
the atmosphere such as sulfur dioxide, nitric oxide, carbon monoxide, dust and mercury. Using
hydropower prevents the burning of 22 million gallons of old or 120 tons of coal each year.
Since water is naturally recurrent; there is no dependency on foreign prices, transportations and
production changes. Hydroelectricity is also very efficient being able to convert as much as 90%
of available electricity into energy whereas fossil fuels are only about 50% efficient.

Even though there are many advantages to using hydroelectricity, there is also several crucial
drawbacks. By increasing water flow by building a dam, flooding can occur to nearby land,
impacting local vegetation and people who live in that area. Local wildlife and farmland can
be lost. The construction of a dam can alter a rivers natural function and create long term
environmental hazards. Another disadvantage that needs to be taken into consideration is the
unreliability of rainfall in certain areas, which will lead to low energy production.

Solar energy is a cost effective, renewable, pollutant free alternative source of energy. Solar energy is the radiant light and heat produced by the sun. It’s free and its supplies are limitless. Using a range of technologies, energy generated from the sun can be converted into useable forms of energy, such as thermal or electrical energy. There are two main approaches, solar thermal and photovoltaic technologies, to convert solar energy into energy that we use.
Solar thermal energy is used to generate heat from the sun. Solar thermal energy works by generating heat by using lens and reflectors to concentrate the suns energy into a small area. There are several common forms used to concentrate the suns energy: parabolic trough, dish stirlings and solar power towers. Parabolic trough is currently the most developed and proven solar thermal technology.
A parabolic trough is a large, curved mirror it is on a motorized receiver that follows the movement of the sun throughout the day. The mirror’s shape is designed to help it collect a great deal of sunlight and then reflect it onto a single point, concentrating the solar power. A receiver tube sits at the point where the mirror concentrates all the sunlight. The tube is filled with a working fluid that is heated by the mirror’s light. The fluid is then pumped from the heat source to a nearby power station.
Dish stirlings consists of a solar concentration in a dish structure that supports several curve glass mirrors. The dish tracks the sun throughout the day and concentrates the light onto a stirling engine that generates heat.
Solar power towers convert sunlight by utilizing many large sun tracking mirrors to focus sunlight on a receiver at the top of a tower. The receiver contains a fluid deposit that is then heated and used to generate steam. The steam is then used in a turbine-generator power station to produce electricity.
Photovoltaic’s uses photovoltaic cells or solar cells to directly convert sunlight into electricity. Photovoltaic cells are made of semi conductors. Semi conductors must have at least two electric fields. When light strikes the cell, a portion of it is absorbed in the semi conductor. When this happens, electrons are released, allowing them to flow freely. The electric fields of the semi conductor forces the freed electrons to move in a specific direction. This flow of electrons creates an electric current that can be used as electricity.

Producing energy, by mining for tar sands and oil shale’s, are some of the dirtiest, most environmentally and wildlife destructive sources being used for energy today. However with an increasing need to find alternative sources of energy, the use of tar sands and oil shale’s have become one of the most wasteful, unconventional ways to generate energy.
Tar sands are a combination of the materials clay, sand, water, and bitumen. Bitumen is a heavy, black viscous oil that can be mined and refined into oil by heating the sand and water material, thus releasing the oil to be collected. However, this is a very complicated, unconventional ways to process oil.

Conventional oil is typically extracted by drilling oil wells, which allows the natural flow of oil into a petroleum reservoir. However extracting oil from tar sands is much more difficult due to the fact that bitumen oil flows very slow, therefore extracting it requires additional, unconventional techniques. Tar sands are mined using strip mining or open pit mining. These systems require enormous amounts of energy and water and emit three times as much global warming pollution as conventional oil production.

Production of oil from oil shale is an extremely costly and environmentally unfriendly form of oil extraction. Oil shale is any sedimentary rock that contains the solid bituminous materials called kerogen. When the rock is heated, petroleum-like liquids are released, however in order extract the oil; it is very expensive and complicated process. Like tar sands, oil shale’s cannot be pumped directly from the ground. Therefore the oil shale must first be mines and then heated at a high temperature and the resulting liquid then must be separated and collected. Mining for oil shale also leads to many environmentally damaging effects to our environment. The land used for mining is damage and the process of oil extraction of oil shale’s leads to the emission of high amounts of harmful greenhouse gases.

Therefore is mining for tar sands and oil shale’s really an alternative to conventional oil extraction? Taking into account the variety of environmental impacts, global warming and green house gas emissions, and impact on wildlife, air and water quality, tar sands and oil shale’s may be one of the most unconventional, harmful, costly, and dangerous forms of alternative energy production.

Wave power is a renewable resource where energy is generated by the interaction of wind and water creating waves. Waves are caused by wind blowing over the surface of the ocean, creating waves to rise and fall. An immense amount of power is created with the falling and rising of waves. With that immense amount of wave power, energy from waves can be harnessed to generate electricity.

In order to tap into wave power, there needs to be exposure to waves and some sort of power station needs to be developed and installed in order to convert wave energy into useable energy. Since there are extreme difference in wave power generated throughout the world, and also cannot be generated effectively in all parts of the world, generating wave power is extremely difficult and power stations are rare.

There are several methods that are being used as power station to capture useable energy from waves. The oscillating water column is a device that is submerged or on the surface. Water is trapped inside a chamber with air trapped above it. The waves cause the trapped water column to move up and down or back and forth. This motion is then used to drive an electric generator. Overtopping devices are filled by incoming waves to levels about the surrounding ocean. The water is then released, causing it to fall back toward the ocean surface. The falling water generates energy by turning a hydro turbine. A point absorber is a floating structure that moves in accordance with wave action. The motion is used to drive electromechanical energy converters.

Wave power is an inexpensive, pollutant free form of reusable energy. However with the inconsistency of wave power, and the durability needed in power stations to withstand extreme weather conditions, power stations designed to use wave power are still rare.

Using wind power to generate energy is one of the most promising alternative energy sources today. Wind power has been harnessed and taken advantage of for thousands of years with the windmill design used to pump water and grind grain. Gradually, windmills have been upgraded to wind turbines. Wind turbines have a huge potential to generate great amounts of useable energy, without the harmful effects to our environment and atmosphere.
Wind energy is the utilization of the energy that moves the air. Wind energy in essence comes from the sun. When the sun heats up the surface of the Earth, the air becomes warm and moves up towards the atmosphere. When the warm air rises up it creates a void where cooler air rushes to fill that void and this air rushing to fill the void is called as wind. This wind can then be captured and turned into electricity. As long as the sun exists, wind will be created, thus it is an efficient, renewable source of energy.
The energy of the wind is converted into useable wind power by the use of turbines. Wind turbines have blades which are meant to intercept the winds passing through them. As the turbine blades intercept the winds, they start moving and the movement of the turbine blades produces power. The turbine is attached to a generator which converts the rotational energy into electric energy.
There are two basic categories of generating energy from the wind, commercial and micro. Turbines used for commercial production are found on turbine farms where there can be hundreds of three bladed turbines capable of producing larger amounts of electricity used for agricultural and other uses. Wind farms are typically found in open areas where there are strong steady winds. The turbines in wind farms are very large and tall, in order to be able to extract the most amount of energy from the wind. Micro wind turbines are of smaller stature then those found in commercial wind farms and are typically used to help reduce electrical home costs in urban and rural residential areas. Micro turbines are light, compact and can produce energy with lower amount of winds.
Wind power is a pollutant free, renewable alternative source of energy. Also with the availability of small turbines has led to an increase in use and electrical savings in residential areas. However the amount of wind in an areas and the inconsistency of wind is a disadvantage and problem with relying on energy generated by the wind.