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April 15, 2005


Denis Du Bois

There's another form of geothermal energy that's available everywhere. Geothermal heat pumps can be built into homes, high schools, and hospitals.

GHP technology uses Earth's constant body temperature to supplement or replace conventional heating, ventilating and air conditioning (HVAC) systems.


One very important issue that was not addressed by the author is the risk factor involved in developing geothermal energy resources in volcanically active areas, such as the Cascades.
The same reasons that make geothermal energy resources in volcanically active regions so alluring are the same reasons that make them such a risky undertaking. It is not simply a matter of marring the beauty of a volcano in a national park. It is a matter of significant risk in terms of money, time, manpower, and potentially human life for those working at the plant.
It takes a lot of time and money to set up a geothermal power plant, as the author noted. The financial risk of putting one of these plants on an active volcanic system is huge--an eruption or earthquake could easily destroy the plant. Also, seismic activity, while capable of opening new pathways for geothermal fluids, can also close others, and can significantly alter the groundwater flow regime. All the time and money spent on a particular reservoir could be for nothing if flow patterns were altered significantly enough to render the original reservoir unproductive, or not sustainably productive. Such events cannot be predicted or controlled. Risk assessments can be made, however, and used in determining the best location of a geothermal power plant in terms of maximizing resource potential while minimizing risk potential.
The trick to putting a geothermal power plant in an active volcanic region is not only finding a currently viable reservoir, but also finding one that has enough seismicity to keep pathways open, but not too much seismicity that groundwater flow patterns would be drastically changed and that power plants are at significant risk of destruction by seismic or volcanic activity.
Geothermal reservoirs are definitely effective, clean sources of energy. But great care must be taken in choosing a location for the extraction of these resources. Most, if not all, current geothermal power plants are in areas with low volcanic risk*, but high heat flow. For example, the Rhine Graben in SW Germany is a region with extinct volcanoes, but remaining high heat flow and some seismicity. The geothermal waters in this region have been used for centuries, since the Roman Empire and before. The geothermal power plants in California and Nevada are also in low-volcano-risk zones. See <> or <> for a map of locations.
Putting a plant on an active volcano in the Cascades* as Hook suggests (Section: Environmental) is an extremely poor investment decision. While the heat supply available is seductive, the risks call for pause. Development of geothermal resources in the form of electricity generation will be most advantageous just to the east of the Cascades where heat flow is still rather high, but seismic and volcanic risks are sufficiently diminished.

*While geothermal plants do operate in volcanically active areas such as Iceland and Hawaii, these volcanoes are generally of the non-explosive type. Cascade Range volcanoes do erupt explosively (remember Mt. Saint Helens) and pose a larger threat to human life and property.


Oops. Those links didn't post.

I'll try again.



Check out this introduction article on Geothermal power:


If you have looked into solar energy as a method for heating your home, panels are usually the first things that come up. There are, however, other unique methods.

The Solar Heating Aspect You Have Never Heard of Before

The power of the sun is immense. The energy in one day of sunlight is more than the world needs. The problem, of course, is how does one harness this power. Solar panels represent the obvious solution, but they have their downside. First, they can be expensive depending upon your energy needs. Second, they do not exactly blend in with the rest of your home.

Passive solar heating represents a panel free method of harnessing the inherent energy found in the sun for heating purposes. If you come out from a store and open the door of your car in the summer, you understand the concept of passive solar heating. A wide variety of material absorbs sunlight and radiates the energy back into the air in the form of heat. Passive solar heating for a home works the same way as the process which overheats your car in the parking lot.

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