2 negative points about geothermal energy?

Question

2 negative points about geothermal energy?

Answer 1

1. Hot geothermal waters contain dissolved minerals which precipitate in the pipes and turbines.

2. Geothermal sites are often remote form load centers, meaning that long power lines have to be built.

Answer 2

There are many different types of geothermal energy, so the problems vary considerably, and vary according to location. For geothermal wells:

1. One of the biggest problems so far with geothermal wells has been maintaining a sustainable rate of production. This has been solved in most cases, but still presents a threat that production (removal of heat) may exceed the rate at which the heat is replenished, leaving the wells non-economic.

http://geoheat.oit.edu/bulletin/bull19-2...

The decline problem is well demonstrated by the experience at the Geysers in California:

I quote: "At its peak in 1987, the field produced almost 2,000 megawatts (MW), enough electricity to supply an estimated two million homes and businesses with power.

That rate of production soon dropped, though, says Mitch Stark, a seismologist at the Calpine Corporation, "because the steam supply was no longer sufficient to keep up with all the new plants and wells that had been drilled." By the late 1980s, companies had drilled about 600 wells. Today the field produces about 1,000 MW from only 350 wells. In 1999 Calpine bought out most of the other producers, "unifying the field" under one management strategy."

From http://www.sciam.com/article.cfm?id=cali...

History of the Geysers:

http://www.geysers.com/history.htm

2. Hydrogen sulphide gases are often associated with some types of geothermal fields. Many of these do emit hydrogen sulphide naturally, but danger of this gas to people working at the location and the risk of releases of this very toxic gas is a serious consideration. Inhalation of only a single breath of 1000 ppm H2S can induce a coma. Another problem with the gas is that people can quickly become desensitized to the smell and fail to notice it without special equipment.

http://msds.chem.ox.ac.uk/HY/hydrogen_su...