Finding Geothermal Energy Just Got Easy
by Tim McGee, Helena, MT, USA on 12. 2.07
The ground beneath your feet contains energy, vast sums of energy. It has been estimated that in the U.S. alone the geothermal energy resources are enough to power the entire U.S. for 30,000 years. Yet, there are serious questions about geothermal energy development. It has been named the 'poor cousin' of renewable energy: likely because it is mining a finite resource and there is the little issue of causing earthquakes. Yet it is also a non-polluting, constant source of energy that is readily available using todays technology.
No matter if you decide it is a good option or not, one outstanding problem with geothermal energy is that it can actually be tricky to find. Sure, we have 'heat' maps like the one shown below (the fold), but the only surefire way to tell if geothermal energy sources are easily available is to drill, which can be an expensive endeavor. Now scientists have found an easy way to tell if geothermal energy could be bubbling up in your neck of the woods.
“We wanted to show that certain surface indicators, specifically the ratio of helium isotopes, can be used to identify areas with high resource potential for geothermal energy,” says van Soest, co-author of a research report that appears in the Nov. 30 issue of the scientific journal Science.
The Earth's crust and mantle differ in their ratio of helium isotopes. Usually, helium-4 is more abundant in the crust, and helium-3 is more abundant in the mantle. So, the research team looked to see if the water at known geothermal areas contained a different ratio of helium isotopes.
“When we found the elevated ratios, we knew that the only way these waters could be enriched with helium-3 was if they had interacted with fluids from the Earth’s mantle,” explains van Soest.
Thus, to find a geothermal hot spot for energy generation, measure the helium isotope ratio in groundwater, and if it is high in helium-3 you have yourself a potential spot to drill. This technique could be used to map the potential of geothermal areas, and determine where geothermal technology will be most effective, hopefully with the least environmental damage, or seismic risk.
Although geothermal is not without its own long-term consequences, this research may go a considerable distance to ensure a safer, and more readily available energy source in the near future.
::Eureka Alert ::Geothermal - The Energy Under Our Feet (PDF)
Geo thermal is not just tapping into hotspots!!!!
The cheapest most cost effective form of geothermal is simply using the difference in temperature between the earth and the air to produce electricity.
*****
Authors Note:
There are several types of geothermal energy, I'm not familiar with what you describe- but it sounds a little bit like a geothermal heat pump (GHP) - which indeed are useful as heat exchange systems- but they are not used for power generation for electrical services.
More specifically, I assume the technique described in the article would be primarily useful for hydrothermal energy systems.
Do you have links where I can learn more about the air to ground (sterling engine?), and are there any in use for electricity production?
Geothermal power is a finite resource in the exact same way that solar is - maybe we'll have to worry about it running out when our race is 100 times older.
It's funny how we worry about so much, when there are answers to our fears.
I guess the government has yet to find a way to make money off of geothermal. Maybe they have, but it wouldn't be as profitable as oil is.
Adam
Geothermal is a finite resource?
Maybe you should stick to Biology, Tim, and leave the geology to the professionals.
****
Authors Note:
Oh- smack.
Well, I guess it depends on what you mean by finite, and what KIND of geothermal energy you are talking about (as there are several)
From a DOE website I clipped the following:
"Some owners and operators of power plants at The Geysers have learned that the resource must be intensively managed rather than mined for steam. The notion of an inexhaustible thermal resource (within the bounds of existing extraction and generating capability) has been clearly proven incorrect. Since the late 1980s, when the steam decline became both noticeable and sustained, six plants, totaling approximately 200 megawatts, have been retired or suspended. Most other plants have been effectively derated due to declining steam production. Reinjection of consumed steam has been successful in slowing steam declines but thus far has not been shown to increase steam production to the levels that prevailed in the late 1980s."
The International Geothermal Association (IGA) also has this to say on the subject:
"The most critical factor for the classification of geothermal energy as a renewable energy source is the rate of energy recharge. In the exploitation of natural geothermal systems, energy recharge takes place by advection of thermal water on the same time scale as production from the resource. This justifies our classification of geothermal energy as a renewable energy resource. In the case of hot, dry rocks, and some of the hot water aquifers in sedimentary basins, energy recharge is only by thermal conduction; due to the slow rate of the latter process, however, hot dry rocks and some sedimentary reservoirs should be considered as finite energy resources (Stefansson, 2000)."
So I question the rationality of blindly saying it is an infinite resource- and instead error on the side of caution and consider it a finite, and valuable resource not to be dismissed.
30,000 years of widespread mining of geothermal heat could have unintended consequences. Refer to this recent popular review article.
Higher Power; November 2007; Scientific American Magazine; by Sarah Simpson; 3 Page(s)
Topography seems easy to explain when beholding jagged summits such as Colorado's Rocky Mountains or California's Sierra Nevada range. After all, these mountains mark spots where the continent grew thick during violent collisions with other tectonic plates: the land crumpled and heaved skyward, like the hood of a car buckling in a head-on crash.
But surface-shaping geologic forces account for surprisingly little of the planet's highs and lows. About half of North America's elevation actually results from the planet's internal heat. Minus that warmth, most land would sink below sea level, say University of Utah geophysicists Derrick Hasterok and David S. Chapman. Based on their recent calculations, parts of the Rockies and high Sierras would shrink to mere islands, whereas cities such as New York, Los Angeles and even milehigh Denver would slip 200 meters (700 feet) or more underwater.
Did you say "little" issue of causing earthquakes? When earthquakes became a "little" issue? Have you ever encountered one yourself?
****Authors Note***
Could be a cultural difference here- by highlighting the 'little' issue- it is in fact saying it is NOT a little issue- this is known as sarcasm, and I do use sarcasm in my writing. It can be confusing to some people who are not familiar with the style.
My own ignorant comment would be that utilizing geo-thermal energy would only be a stop gap measure until other energy generating systems would be invented. I would think that the full loop or the binary generation system producing zero emissions would be the logical way to generate electricity for the next 50 years until better systems are designed. New plant generation costs are estimated to be about 6 cents a K/W hour. This should make all the tree huggers happy. Additionaly, this would not finance those who are out to replace Western Civilization with their own cocept of the perfect Caliphate. Once again, an ignorant opinion would be that we would not be able to create substantial subterainial faults in 50 years.
PS: I got 93 very fat and happy cows eating ethanol by-product mash and syrup.