by Lenna Gonya

Created on: August 17, 2010   Last Updated: August 18, 2010

Every development has it drawbacks, and alternative energy is no exception. While energy sources such as wind, solar, and geothermal are considered good sustainable solutions, there are some problems that scientists are concerned about, and that they are in the process of working out.

Any heat that is beneath the surface of the earth is geothermal. This heat has been used by utilizing hot water or steam in the earth, but now, deep drilling has been proposed to use even more heat from rocks, further beneath the earth’s crust.

The problem isn’t with the ability to use the heat from these techniques as much as the possible problem with byproducts that may come out with the heat. Some hydrogen sulfide, ammonia, methane and even carbon dioxide may very well be expelled into the atmosphere where these geothermal wells are drilled. Metal and minerals are other byproducts, and some are afraid that in a large scale system, the combined chemicals and their fumes might well be hazardous to workers or those who live in the vicinity.

Currently there are two systems of utilizing geothermal energy, the open, and closed systems. These systems differ in their technique, ability to control pollution and in the overall cost.

The closed loop system does allow waste and fumes to filter into the atmosphere, but instead, injects it back into the rock. This is the most expensive system, but it eliminates the cost of disposing of waste.

The open loop system, a less expensive option, and one that scientists are worried about, allows metals and fumes to escape, however, it still only releases 5% of the carbon dioxide per kilowatt hour that a coal fired system generates.

There is also the question of sludge, that is produced from scrubbers, which reduce emissions. These sludge areas can contain harmful, possibly toxic levels of chemicals.

Finally, where the waste has not been injected back into the rock, around geothermal areas, the land may become unstable, and has actually collapsed, which could prove dangerous, especially in already low lying and flood prone areas.

While geothermal is certainly on the list of alternative energy sources, there is still a lot that needs to be discovered as to the method of obtaining it, and the way that waste products and gases are disposed of. The earth holds both heat and a lot of byproducts, some of which are not healthy when brought to the surface.

http://www.ucsusa.org/clean_energy/technology_and_im pacts/impacts/environmental-impacts-of.html

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