Slashdot Mirror
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."
I guess we already "make" this heat to power the turbines in power stations(i.e. we transform other types of energy into heat), so I would be inclined to say that using geothermal power would not result in a net increase of heat output on the surface. Unless perhaps, that that now guilt-free and cheap electricity causes everyone to go on a leccy binge for the next 200 years and consumption goes through the roof.
I recently visited Iceland where they use the country's ample supply of superheated steam to produce electricity (and provide hot water and heating). A related question that sprang to mind was "if the rest of the world did this, what would be the effects of letting all that heat out? Would the amount of heat that we would cause to escape from the planet's core be significant? We need a geophysicist to give a proper answer to that - but I'm a suspicious bugger and all this "free" electricity looks too good to be true - you know what they say about free lunches. Essentially, we'd be using the planet like a battery: it's just a question of how long it will last - millions of years? Thousands?
One of the other things that struck me about what the Icelanders are doing, is that they may just have struck their country's equivalent of oil. In the past, they couldn't really export their natural resource - steam goes off quite quickly. Then, they figured out how to make electricity with it, which is a bit easier to store and transport, but not out of the country. Now though, it looks like there may soon be a large world market for hydrogen, if fuel cells and other hydrogen consuming automotive engines take off. Iceland has all the ingredients to produce it - seawater, and abundant electricity. There are a number of problems to overcome in transporting it safely, but I reckon these guys may soon be rolling in it.
The Shell petrol station in Reykjavik already sells hydrogen. It's not clear who to exactly right now, but Shell obviously believes it has a future.
TFA says the goal of the project is nice, but cost is a big barrier. "A so-called hot rock well three miles deep in the United States would cost $7 million to $8 million, according to the MIT study. The average cost of drilling an oil well in the U.S. in 2004 was $1.44 million, according to the U.S. Energy Information Administration."
/ Spending.asp#USMilitarySpending US military spending was over $570 Billion in 2006. So why not spend, oh, say one percent of that figure to go towards coming up with clean energy?
Yea, so that's about six times more expensive. But wouldn't the savings be much more in the long run? And more "environmentally friendly"? After all, according to http://www.globalissues.org/Geopolitics/ArmsTrade
The Wknd Sessions - Malaysian and South East Asia independent music
It includes injection, but the key part is drilling into hot parts of the earth's crust, fracturing the rock, then injecting water into the fractured rock and harvesting the steam.
Both the summary and TFA are a little misleading. HDR is being tested in many parts of the world, including Japan, France, Australia and the US. The Australian site is here; http://www.geodynamics.com.au/IRM/content/home.htm l.
It's a promising approach to clean power generation, but it won't work everywhere. HDR relies on a steeper than normal thermal gradient. Temperature rises with depth at a rate of about 20c/km on average, so hole depths without the steep gradient are too great for power generation to be economically feasible.
"I've got more toys than Teruhisa Kitahara."
If they dump excess heat in a nearby river it has a very real environmental impact. Lot's of fish get into trouble if the water they live in rises in temperature too much. In holland we have had a few occasions where the national grid operator, TenneT, gave a 'code red' because electricity supply was becoming endangered, because power plants could no longer dump excess heat in the rivers because the temperature got too high. At some point they can't dump the heat anymore and have to shut down.
Another thing to keep in mind is that with an effectively infinite energy source (with non-infinite power output), lower cost does not automatically mean lower profit. The laptop I'm typing on probably has more processing power than all the computers in the world back in 1975 combined, but does that mean my laptop is the only computer that was sold last year? No, Intel and AMD are selling more processors than they ever have. Lower energy cost just means people would come up with more ways to use energy, not continue to use the same amount of it.
Hardly. Transportation energy sources have several requirements to which gasoline is well suited. Cost, high energy density (both volumetric and weight), ease and speed of distribution (refueling or recharging), and safety are some that come to mind. A cheap energy source like geothermal would take care of the cost requirement, but energy density (range) and distribution (time to recharge) would still remain a huge hurdle to electric vehicles. Also, most existing car manufacturers are at the forefront of electric vehicle development, and if they aren't they'd just buy up any electric car competitors to insure they stay competitive. Right, which is why this is, as I asserted, a political problem; not one of oil companies conspiring to hold back technology.