Geothermal Energy and its Potential Applications in the United States - Essay Example

Geothermal energy is classified amongst the group of renewable energy sources: these forms of power utilize energy flows from natural processes like the suns radiation, wind, running water and in this case, magma heated water(" Renewable Energy", Wikipedia). Renewable sources replace the drawn energy through natural processes. In this sense, geo power is not strictly renewable as it is possible to exhaust a particular source by drawing it out faster than it can be replenished. It is most definitely sustainable by re-injecting the spent fluid back into the earth to be reheated.

Since it is derived from the earths own heat it can be utilized almost any where in the world, though currently it has only been done so predominantly in the West. It is also one of the cleaner forms of energy, with lower green house emissions than fossil fuels, puts less stress on the environment as it its power plants are small and it does not require dam construction or forest depletion (Geothermal Energy Facts,Geothermal Education Office). The most common application of geothermal power is electricity generation.

In fact the United States alone uses 2,800MWe of electrical capacity and this is only a fraction of its capacity.(Fridleifson,n.d, www.crest.org). Idaho National Laboratories list three types of power plants for electricity generation and all three are hydrothermal in source, i.e from hot water reservoirs. (The first type is known as dry steam plants. Steam from underground reservoirs is pumped up into turbines and used to drive a generator. Flash steam plants utilize reservoirs with extremely high temperatures greater than 182 C.

Here, water is driven to the surface under its own pressure. When it reaches the surface the pressure drop forces it to become steam and this is then used to drive a turbine. The third type, binary flows, make use of geothermal reservoirs with lower or milder heat conditions. Hot water, at temperatures lower than boiling (100 C), is pumped through a set of pipes known as heat exchangers and is used to heat an organic volatile fluid in the other pies. The fluid then evaporates into steam which is used to power a generator.

In all three types the condensed steam or water is re-injected into the fractures from wherein they were drawn thus replenishing the heat source. From the vastly different temperature ranges observed in the three methods listed, it is evident that even mild temperatures can be used to generate electricity. Considering the United States vast consumption of oil - more than 20.8 billion barrels per day, and its growth, the scope for more geothermal power plants is enormous. Currently, only 0.5% of the U.S. power is supplied by geothermal power.(U.S.

Energy Policy,www.solcomhouse.com). Costs are also quite competitive, being only $0.05 -$0.08 per KWh (www.crest.org).Direct utilization of geothermal power for heating buildings and water is another option. This makes use of shallow ground water sources with lower temperatures (20-150C) and thus may be limited to those areas which have access to them. However it is an extremely cost effective method to heat greenhouses and homes, and can be used in small scale industry like fishfarming. Direct use systems make use of heat exchangers wherein the source water is pumped through one set of pipes and the heat