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School to Research Gas and Oil Technology for EGS Adapted from a News Release by the Colorado School of Mines In the search for reliable, carbon-free electricity, geothermal energy has gained a great deal of attention. The same tech- nology which fueledAmerica’s oil and gas boommay be putting this resource within reach. A col laboration between the Colorado School of Mines (Mines) and the U.S. Department of Energy’s (DOE) National Renewable Energy Laboratory (NREL) is working to use the tools of mod- ern gas and oil extraction to develop geo- thermal resources. The concept behind EGS (enhanced geothermal systems) is simple: inject water into hot, dry rock; let the hot rock heat the water; extract the hot water as steam; drive a turbine with the steam; produce electricity; reinject the cooled water; and repeat. The Mines-NREL Colorado Collaboration for Subsurface Research in Geothermal Energy (Colorado SURGE) is getting into those details on projects spanning geothermal reservoir characterization, drilling approaches, and water treatment. The effort, launched in 2014, is being paid for by funding from DOE starting with $800,000 in 2014 and $1.2 million in 2015. Future years funding will depend on the progress and independent review of proposals, but the Colorado SURGE team is planning for growth. “The idea of adapting advanced oil and gas technologies for geothermal was a very high priority for the DOE,” said Dag Nummedal, who directs Mines’ Colorado Energy Research Institute and worked with NREL to launch SURGE. In early 2015, Mines Professor Wendy Harrison, just back from an 18-month appointment leading the National Science Foundation’s Earth Sciences Division, took over SURGE leadership at the school. Tom Williams, who directs NREL’s Geothermal Technologies Program and federal lab’s side of SURGE, said NREL had recog- nized their lab lacked capabilities in geology, oil and gas technology, water treatment, and other areas critical to EGS - not to mention access to students. Mines, right up the road, was the obvious choice, he said. The conclusion so far is, while the technology piece is tough, the real hurdles are economic. The key, will be to improve an array of technologies and techniques, particularly on the drilling side, to bring the costs down. A 2008 U.S. Geological Survey estimate on the heat beneath 13 western U.S. states suggested a potential geothermal resource of roughly 345-727 gigawatts. In 2011, Google.org and Southern Methodist University’s Geothermal Laboratory estimated the technical potential of EGS, accessible at depths of about 11,500-21,000 feet, to be 2980 gigawatts. The entire U.S. electrical generation capacity amounted to 1051 gigawatts in 2011. The problem is you’ve got to get down there, and the shallow side of EGS is the deep end of oil and gas drilling. To reach the minimum temperatures necessary for geothermal power production (300ºF or 150ºC) in places like Michigan and Florida, you’d need to drill over 32,000 feet (roughly 6 miles). Since the most favorable EGS targets in the West are in granite formations, as op- posed to the sedimentary formations where tight oil and gas are harvested, drilling is a lot slower and more expensive. How hydraulic fracturing might work in those formations at high temperatures and pressures isn’t well-understood. Additionally, EGS wells are larger in diameter which adds to the cost. In fact, an MIT (Massachusetts Institute of Technology) team estimates the cost of an EGS well could be up to five times more costly than an oil and gas well. Not to mention, in oil and gas drilling the deeper you drill, the more it costs. According to the MIT team, it costs an average of $600,000 to drill to 6500 feet, this increases to $10 million or more at 19,500 feet. Associate Professor Bill Eustes and Professor William Fleckenstein have two un- dergraduates and a graduate student looking at the feasibility of horizontal geothermal completions. Other graduate students are doing EGS fracture stimulations and studying thermal cycling on casing strings and other drilling hardware. Nine Mines undergradu- ates are looking at drilling performance of oil and gas versus traditional wet-rock geo- thermal, trying to figure out the limitations and gain insight into what might be done to improve drilling operations. EGS researchers around the world have a long way to go. Globally, EGS is in the demonstration stage, with commercial deployments yet to come. Williams said DOE is playing the long game, saying he sees EGS as a very early-stage technology, the same way photovoltaics was in the early 1960s, when solar panels cost thousands of dollars per watt (today, rooftop panels can be had for less than $1 a watt). 2",/ # / 4%,/#03())$ ',+$ 5 ),4"$+1$/ ),,- -2*- *,#2)$0 /$ 3 () !)$ %,/ !,1' /$0(#$+1( ) +# ",**$/"( ) &/,2+# ),,- '$ 1(+& +# ",,)(+& 0601$*0 ,*- 1(!)$ 4(1' 1'$0$ -2*-0 ),4"$+1$/0 " + !$ ",+ %(&2/$# 4(1' ,/ -2*- 2+(10 1, * 1"' #(% %$/$+1 ), # /$.2(/$*$+10 /,#2"10 (+")2#$ ),4"$+1$/0 7 $,1'$/* ) ),0$# ,,- (11(+&0 7 $-) "$*$+1 2*-0 7 ,0$ (10 +# ""$00,/($0 7 /( !)$ -$$# 2*-0 Graduate student Robert Duran and Associate Professor Wendy Zhou conduct a scanline survey on the discontinuities of a rock mass in the Colorado School of Mines’ Edgar Mine in Idaho Springs, Colorado. 20 FEBRUARY 2016 WorldWide Drilling Resource ®