The Potential of Geothermal Power

EskimoJoe wrote with a link to an AP article about progress in the development of geothermal energy. A Swiss company is competing with another in Australia to be the first to commercially develop a geothermal power plant. The concept is simple to understand: earth's core heat transforms water into steam, which in turn causes a turbine to revolve. The potential, though, is enormous. "Scientists say this geothermal energy, clean, quiet and virtually inexhaustible, could fill the world's annual needs 250,000 times over with nearly zero impact on the climate or the environment. A study released this year by the Massachusetts Institute of Technology said if 40 percent of the heat under the United States could be tapped, it would meet demand 56,000 times over. It said an investment of $800 million to $1 billion could produce more than 100 gigawatts of electricity by 2050, equaling the combined output of all 104 nuclear power plants in the U.S."

Comments

Misleading

[Remusti]

The summary is misleading, Geothermal power plants already exist.

Re:Misleading

[blowdart]

Spotty effects? Iceland's geothermal power plants provide 26% of the power there (the majority is from hydroelectric), plus geothermal heating plants heat around 87% of homes. On the other hand the baths and showers I had there did stink of sulphur.

Re:Misleading

[krilli]

Hi, I live in Iceland.

We use hot water pumped directly from shallow wells for the hot tap water. It contains sulfur.

It's close to 100C, so you can use a heat transformer to warm up the non-sulfuric cold water for showers, etc. Some houses here do.

Re:Misleading

[Xemu]

As for African cultures, the majority of the Sahara desert became so because of goats, which were protected from predators by humans.

Wow, that's so misinformed I can only laugh. Do you have any idea on how many goats that would take?

Sahara, for example, was born 4000 years ago because of a climate change. Land use by man was not an important factor in the creation of the Sahara. http://news.bbc.co.uk/1/hi/sci/tech/390097.stm

Huh?

[jawtheshark]

A Swiss company is competing with another in Australia to be the first to commercially develop a geothermal power plant.

I think they should go on a trip to Iceland... Frankly...

Just 40% They say..

[Yazeran]

Well they may be right that just 40% of the heat flow through the continental shield of the US may meet the energy demand 56k times over, the ticklish part is extracting the energy in an economic way. So far the only places where geothermal energy is usable is near active Volcanic areas where the geothermal gradient is steep enough to allow high temperatures near the surface and thus a high enough energy density to make the investment profitable (Think Iceland and California). All the other places the heat flow is too low to be usable for anything else than house heating.

Another thing one must address is that the heat flow can only be used where permeable strata exists in the ground making it possible to circulate water to extract the heat. In places with crystalline bedrock, the heat flow can not be used.

Yours Yazeran

Plan: to go to Mars one day with a hammer.

Remember "The Core"?

[Chmcginn]

No, not the part about the burrowing ship & the nukes and everything. If we actually managed to make a noticeable difference in the outer core/mantle temperature, it would weaken the Earth's magnetic field.

That being said, Earth is about 6E24 kg. The specific heat of silica & iron (the two most common minerals) is .7 & .45 J/gk - average it to .55. That would mean 3E24 J for a 1 degree drop. 3600J is a watt-hour... so 2.1E19 J is a terawatt-year. That means it would take about 140,000 years of 1TW 'drain' to cool the entire (interior of) earth about 1 degree. Even assuming that all human electricity was generated via geothermal energy, it would take somewhere in range of millions of years.

So, yeah, I wouldn't really worry about it.