January 14th, 2012 by Michael Ricciardi
[Updated article, Jan. 18, 2012, with correction, see end note] Geothermal power has had a few setbacks in recent years: technical challenges and concerns that high-pressure pumping of water onto bedrock triggers earthquakes being the biggest ones (possibly two 2009 projects, one in California and one in Basel, Switzerland, were stopped over earthquake concerns).
But, in the hunt for a renewable energy source that is not sun or wind-dependent, geothermal power is making a come back… if it ever really went away.
In this newest plan — testing of which will commence mid-summer 2012 — 24 million gallons of water (at 800 gallons of water per minute) will be pumped deep into the side of an inactive volcano in central Oregon State. Once the water penetrates to the right depth (about 6500 – 10,000 feet down), it will come in contact with hot bedrock (heated by magma below it). There, the heated and pressurized water will return to the surface where its heat energy and pressure can be harnessed by a turbine to make “cheap, clean electricity (note: apart from the downward pressure of millions of gallons of water, the contained water further increases in pressure as it is heated).
The project, a joint venture of two companies: AltaRock Energy, Inc. of Seattle and Davenport Newberry Holdings LLC of Stamford, Conn., has been given 21.6 million in stimulus funds from the U.S. Department of Energy, and has attracted the attention and interest of Google (headquartered in the state) and others, who have so far invested over 40 million dollars in the project.
By coincidence, perhaps, the name of the volcano is Newberry Volcano, and is located about 20 miles south of Bend, Oregon.
What is the technology used in this hydroshearing process?
Although geothermal energy has been exploited in various ways for at least a century, this newest plan makes use of a new technology called Enhanced Geothermal Systems.
In this new technology, wells are drilled deep into the bedrock (which is hotter due to heating from magma beneath it) and cold water is pumped in, creating tiny fractures in the rock, a process known as hydroshearing.
This may sound a lot like hydraulic fracturing (‘fracking’), and, indeed, it is — except that, in fracking, diesel fuel and hundreds of toxic chemicals are mixed in with the hydraulic fluid. Also, according to EGS engineers, the fracking process creates much larger fractures in the rock.*
Hydroshearing is utilized to avoid this danger.
Still, the drilling process is similar enough to hydraulic fracturing that public concerns over earthquakes remain. Further, this technology requires an enormous amount of water to keep a commercial plant operating long-term. This will mean building a sufficiently large reservoir nearby to store the many millions of gallons of water necessary.
Addressing this latter need, one of the EGS developers, Altarock, is also planning on demonstrating a new technology for creating bigger reservoirs made from the same plastic polymers used to make biodegradable cups. The synthetic has been shown to work in existing geothermal fields, which require less water than the EGS plants.
*Author Note: Industry engineers note that the drilling aspect of the fracking process does not cause earthquakes, rather, it is the pumping of fluid into disposal wells that cause said quakes, but, from a whole systems point of view, since the disposal of the fracking fluid is conducted in this manner, and this disposal component is a part/consequence of the fracking process, ipso facto, the fracking process leads to earthquakes. Nonetheless, this distinction is duly noted here.
What is the current track record of existing EGS plants?
Currently, there are two small plants online — one in France and one in Germany. In 2009, a geothermal plant in downtown Basel, Switzerland, was shut down permanently due to government concerns over earthquake costs A fourth project, in Australia, has been experiencing drilling problems.
For more information of the association between geothermal power and earthquakes, check out the 2009 NY Times article Geothermal Power by James Glanz and the Daily Finance article Fear of earthquakes halts promising geothermal projects.
The developers and industry investors are hoping that a new, international protocol (due out at the end of the month) will allay some public concerns by establishing the ‘sanity test’ to keep such EGS projects out of urban areas, and to maintain an accurate and timely communications policy with local residents.
What do the geologists say?
According to scientists at the US Geologic Survey, the danger of a major quake at Newberry is very low, as the area is described by geologists as a “seismic dead zone” with no significant faults. Further, many layers of built-up volcanic ash lay atop the rocks and will dampen any shaking, should that occur.
Currently, just 0.3 percent of our nation’s electricity comes from geothermal power. But, according to a 2007 MIT report, EGS could increase that share to 10% within 50 years with a cost competitive with fossil fuels (assuming we are still using fossil fuels 50 years from now).
One thing is for certain, the eyes of the renewable energy industry, and the environmentally concerned public, will be on Newberry Volcano this summer, as the first tests of the water circulating system commence.
For more information, check out the original source article: Project to pour water into volcano to make power.
CORRECTION: An earlier version of this post stated that “two geothermal projects” — one in California and one in Oregon — were shut down due to earthquake concerns. In fact, there was but one 2009 operation in California (by Altarock) that was stopped because of drilling problems, not due to earthquakes, although local residents had experienced and complained about low level quakes during that time due to other concurrent energy projects in the area. No causal link between the Altarock geothermal drilling and earthquakes was found. No Oregon State geothermal project was shutdown. I apologize for the error.
Top photo: (Newberry Caldera, with Paulina Lake, East Lake, and Big Obsidian Flow) USGS photo by Lyn Topinka
Diagram: (EGS diagram) “Siemens Pressebild” http://www.siemens.com
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