What is the disadvantages of using Geothermal power?

Geothermal Energy
Advantages:

Geothermal energy does not produce any pollution, and does not contribute to the greenhouse effect.The power stations do not take up much room, so there is not much impact on the environment.No fuel is needed. Once you've built a geothermal power station, the energy is almost free.It may need a little energy to run a pump, but this can be taken from the energy being generated.

DISadvantages:

The big problem is that there are not many places where you can build a geothermal power station. You need hot rocks of a suitable type, at a depth where we can drill down to them. The type of rock above is also important, it must be of a type that we can easily drill through. Sometimes a geothermal site may "run out of steam", perhaps for decades. Hazardous gases and minerals may come up from underground, and can be difficult to safely dispose of.

Advantages

* Theoretically inexhaustible energy source
* No pollution
* Often an excellent supplement to other renewable sources
* Does not require structures such as solar panels or windmills to collect the energy--can be directly used to heat or produce electricity (thus very cheap)

Disadvantages

* Not available in many locations
* Not much power per vent

The commercial viability of geothermal power production is influenced by capital costs for land, drilling, and physical plant; operating and maintenance costs; the amount of power generated and sold from the plant; and the market value of that power. However, because geothermal power plants incur high capital costs at the beginning of the project, they are typically at an economic disadvantage to conventional fossil fueled power plants.

2007-01-27 09:00:48 補充：
Geothermal powers are also characterized by the fact they are generated mainly in resource-rich natural areas, and yield only certain amounts of energy.

2007-01-27 09:03:35 補充：
so that not every place could yiled considerable amount of energy.