Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Making Geothermal More Productive: $10.2 Million Study

09.09.2009
University of Utah researchers will inject cool water and pressurized water into a “dry” geothermal well during a five-year, $10.2 million study aimed at boosting the productivity of geothermal power plants and making them feasible nationwide.

“Using these techniques to increase pathways in the rock for hot water and steam would increase availability of geothermal energy across the country,” says geologist Ray Levey, director of the Energy & Geoscience Institute (EGI), which is part of the university’s College of Engineering.

EGI geologist Joe Moore – who will head the research effort at U.S. Geothermal Inc.’s Raft River power plant in southeast Idaho – says most geothermal power in the United States now is produced west of the Rocky Mountains, where hot rocks are found closest to the surface.

“Hot rock is present across the United States, but new methods have to be developed to use the heat in these rocks to produce geothermal power,” says Moore. “We want to use oil and gas industry techniques to create pathways in the rock so that we can use the heat in the rocks to generate electricity.”

“There’s incredible potential in Utah and other states for geothermal development,” he adds. “Engineered geothermal systems [in which water is injected to enhance natural cracks in the rock] could provide a means of developing these resources much faster.”

The U.S. Department of Energy on Sept. 4 signed an agreement with the University of Utah and EGI to pay almost $7.4 million of the project’s cost.

The University of Utah is providing $1.1 million through the Office of the Vice President for Research. Another $1.7 million will be provided by discounts or cash or in-kind donations by two of EGI’s partners in the project: U.S. Geothermal, Inc. of Boise, and Apex HiPoint, LLC, of Littleton, Colo.

Moore says the university’s contribution will help fund involvement of graduate and undergraduate students from the College of Engineering and College of Mines and Earth Sciences.

Experiment at Raft River

“We’re going to take a geothermal field and improve its productivity,” Moore says. “We’re going to test the techniques on one well at Raft River. We’re testing methods to take wells that are not productive and make them productive.”

Moore says the Department of Energy did geothermal research for three decades at the site, located 11 miles from Interstate 84 in southeast Idaho halfway between Boise and Salt Lake City. Raft River is now a U.S. Geothermal power plant producing 10.5 to 11.5 megawatts of electricity – enough for roughly 10,000 homes. The power is sold to Idaho Power Co.

Some estimate the site may be capable of producing 110 megawatts of power. Researchers believe production can be increased because underground temperatures measure 275 to 300 degrees Fahrenheit at depths of 4,500 to 6,000 feet.

The Raft River plant currently has five “production” wells that produce geothermal energy and four “injection” wells where water from the production wells is returned to the underground geothermal reservoir. Water must be re-injected to maintain pressure in a geothermal power system.

One well drilled in recent years did not produce enough hot water to be used as a production well because it did not connect with enough of the underground cracks that carry the hot water.

“Geothermal wells are like oil wells – some wells produce and some don’t,” Moore says. “Drilling wells is expensive. That is why we need to develop low-cost techniques to improve their productivity.”

If the experiments run by EGI work, U.S. Geothermal eventually will operate the test well and put it into service.

Stimulating Geothermal Power by Cracking Hot Rock

To produce geothermal power, hot rock is not enough. The rock also must be permeable to the flow of water and-or steam, says John McLennan, an engineer at EGI. Many geothermal reservoirs have heat, but the rock is impermeable, which is the problem at the Raft River well known as RRG-9.

The experiment will try to make RRG-9 into an effective injection well because U.S. Geothermal must inject more water into the ground to increase the productivity of its existing production wells. Moore says all the water-injection “stimulations” will be done during 2010, with the well monitored over the rest of the five-year study period. All the water will come from production wells, not from streams.

Researchers will first let cold water flow into the hot rocks around the 6,000-foot-deep well, hoping to crack them extensively, and then pump water into the ground under high pressures to force the cracks to open wider. The goal of this “hydraulic stimulation” is to create a network of underground conduits that connect the well with underground cracks that already carry hot water.

“When the cold water reaches the hot rock it will crackle,” Moore says. “Stimulation is the process of generating new cracks.”

Apex Petroleum Engineering, Inc. of Englewood, Colo., will help design the water injection operations to create “hydraulic fractures.” Apex HiPoint’s monitoring equipment will listen to microseismic activity in the rural area to determine the extent of the cracking and thus the growth of the underground geothermal reservoir. Groundwater flow and pressures will be monitored.

Moore says three “stimulations” will occur. During the first two, relatively cool water (40 to 135 degrees Fahrenheit) will flow into the well to crack the rock at a depth of 6,000 feet. Then, a third “stimulation” will involve pumping large volumes of water into the well at high pressure to expand the cracks and keep them open to the flow of water and steam.

The lower half of the well is uncased by piping. The researchers will insert more piping so that the injected water will flow to the depths where it is needed.

McLennan says semi-sized trucks carrying large pumps will come to the well site and may pump as much as 4,200 gallons of water per minute into the ground during each “stimulation.” The total amount injected “could be on the order of 1 million gallons” for each of three “stimulations,” he adds.

The goal, says Moore, is “to create a complex fracture network over an extensive area.”

The Department of Energy wants to develop methods that can “stimulate” geothermal production in various geological environments with various rock types, Moore says. If the techniques used at Raft River prove effective, they could be used anywhere rock is hot.

“It will definitely be an advantage to Raft River if they can improve the productivity of the well, but the Department of Energy is funding this as a research program because hot rock exists everywhere,” Moore says.

The Energy & Geoscience Institute is a contract research organization. Levey says that in terms of the number of participating companies, EGI is the largest university-based research consortium working with the energy exploration and production industry.

In addition to their positions at EGI, Levey and Moore are research professors of civil and environmental engineering at the University of Utah, and McLennan is a research professor of chemical engineering and civil and environmental engineering.

Contacts:

-- Joe Moore, geologist, Energy & Geoscience Institute – office (801) 585-6931, cellular (801) 231-0393, jmoore@egi.utah.edu

-- John McLennan, engineer, Energy & Geoscience Institute – office (801) 587-7925, cellular (801) 634-4412, jmclennan@egi.utah.edu

-- Ray Levey, geologist and director, Energy & Geoscience Institute – office (801) 585-3826, cellular (801) 673-0554, rlevey@egi.utah.edu

Lee Siegel | Newswise Science News
Further information:
http://www.utah.edu

More articles from Studies and Analyses:

nachricht A sudden drop in outdoor temperature increases the risk of respiratory infections
11.01.2017 | University of Gothenburg

nachricht Urbanization to convert 300,000 km2 of prime croplands
27.12.2016 | Mercator Research Institute on Global Commons and Climate Change (MCC) gGmbH

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

Im Focus: Newly proposed reference datasets improve weather satellite data quality

UMD, NOAA collaboration demonstrates suitability of in-orbit datasets for weather satellite calibration

"Traffic and weather, together on the hour!" blasts your local radio station, while your smartphone knows the weather halfway across the world. A network of...

Im Focus: Repairing defects in fiber-reinforced plastics more efficiently

Fiber-reinforced plastics (FRP) are frequently used in the aeronautic and automobile industry. However, the repair of workpieces made of these composite materials is often less profitable than exchanging the part. In order to increase the lifetime of FRP parts and to make them more eco-efficient, the Laser Zentrum Hannover e.V. (LZH) and the Apodius GmbH want to combine a new measuring device for fiber layer orientation with an innovative laser-based repair process.

Defects in FRP pieces may be production or operation-related. Whether or not repair is cost-effective depends on the geometry of the defective area, the tools...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Multiregional brain on a chip

16.01.2017 | Power and Electrical Engineering

New technology enables 5-D imaging in live animals, humans

16.01.2017 | Information Technology

Researchers develop environmentally friendly soy air filter

16.01.2017 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>