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GeoTek Energy to field test Gravity Head Energy System this year

GeoTek Energy to field test Gravity Head Energy System this year GeoTek Energy website snapshot
Alexander Richter 23 Apr 2012

GeoTek Energy, a Texas company, is nearing completion of its design phase for a new technology called Gravity Head Energy System that is to eliminate power need for pumping in geothermal systems.

GeoTek Energy, a geothermal technology firm, has been developing a system that is expected to reduce production expenses for geothermal energy by about 30 percent.

The company is now close to the completion of the design phase for its technology and is looking for a small geothermal well to test a scale model of the technology.

The company has made headlines in the last 12 months through adding industry veterans to its board including Lou Capuano (formerly CEO of ThermaSource) and Hezy Ram (formerly CEO of Ram Power).

The company is developing its technology, called Gravity Head Energy System (GHES), utilizing gravity instead of pumps to capture energy from geothermal water reservoirs to be utilized in a binary power system.

“In a conventional binary,” said Dave Marshall, CFO of GeoTek, “if you’re producing, say, two-and-a-half megawatts (enough to power roughly 2,500 homes), you’re using almost 500 kw to just run your production pump. That’s what is referred to as ‘parasitic load.'” He said another 110 kw is needed to run the working fluid pump, bringing the total parasitic load to 610 kw, or 24.4 percent of the total power produced. GeoTek states that, by eliminating those power needs, their system makes available 30 percent more power to the grid, a number arrived at by starting at the 1890 kwh actually available under standard systems and dividing the extra 610 kwh into that number.

The hot underground water still will flow to the surface in separate tubing from the heated working liquid. The water will then be reinjected in a well some distance away from the source well. The working liquid will be used to generate power, then recycled into the downhole heat exchanger.

With three liquid paths — the hot water flowing up and the working fluid cycling in both directions — the outside diameter of the well must be larger than most oil wells at a greater depth-13-3/8 OD down to as much as 2,000 feet. The GHES pump itself is only 5 inches OD.

While most traditional geothermal plants take five years to begin flowing power into the grid, Marshall expects the GHES system to begin producing power within two years of the start of construction and permitting.

The GHES system was first developed in the 1970s, during the first major energy crisis, but then shelved as the crisis eased. GeoTek, founded in 2004 by a group of local oil and gas investors who wanted to diversify their investments, wanted to further develop an existing system and bring it to market. After considering a number of possible technologies, the group decided to pursue the GHES model, in conjunction with engineers at Ortloff. The Ortloff engineers put their knowledge of gas processing procedures to work in the design, processes that are similar in many ways to the geothermal model, Marshall noted, citing heat transfer and thermosiphon loops in particular.

Years of development funded primarily by the investors began to appear on geothermal industry radar screens when, as Marshall stated, the engineers’ progress was enough to attract the attention of the Department of Energy. Both the DOE and the industry gave the company more feedback on their system. “That brought us to the point where we are literally within nine months of doing a field test of a prototype unit,” Marshall said.

The DOE has helped with some funding to this point, said Ken Fryrear, GeoTek’s COO, but they are not prepared to completely fund the field test. “It will be on a cost-sharing basis,” Fryrear said. “We will pay 60 percent of the cost and they will pay 40 percent,” subject to how Congress decides to fund this type of research.

Because most geothermal activity in North America is in the west, the company expects that to be the location of the test. However, Marshall was quick to point out that the heat exchanger and other components likely will be produced in the Permian Basin. He also noted that, despite some similarity with oil and gas production, using an abandoned oil or gas well for either the pilot program or for long-term power generation is not currently practical.

The small demonstration unit will deliver only a little power, but its only purpose is to prove the concept and to let engineers determine where design improvements are needed. Marshall hopes to find a currently operating geothermal company that will let GeoTek use a small diameter well for 90-120 days for the test.

From there GeoTek will design commercial units in two sizes, available late in 2012 and early in 2013. “Then the plan is (for us) to act as a licensing company, where we will license that technology to companies that are already experienced in manufacturing a lot of the surface equipment like the turbine generators.”

Source: My West Texas, under creative commons license: Attribution