Lessons learned from fracking might help geothermal industry
AltaRock is testing ways to adapt hydraulic fracking to maximize the heat output of geothermal wells, through a process known as hydroshearing, which works at lower pressures and without the fracking chemicals used in the oil and gas industry.
At the beginning of the current year in the Newberry Volcano in Oregon, Alta Rock has been testing a new way to increase the performance of geothermal wells using a similar process to the gas industry uses in shale gas extraction. MIT Technology Review recently published a great article about the AltaRock Demonstration project in Oregon (see link below).
In answering the article, AltaRock clarifies that, while the title Fracking for Geothermal Heat Instead of Gas implies the Newberry EGS demonstration uses hydraulic fracturing techniques, AltaRock uses a process known as hydroshearing, which works at lower pressures and without the fracking chemicals used in the oil and gas industry. For more information on that distinction, AltaRock posted a FAQ #1 and the blog post “Clarifications to Recent Headlines”, here:
Conventional geothermal plants a need a very specific combination of geological features to be viable, mainly hot porous rock at a drillable depth accompanied by large amounts of hot water or steam that can easily be pumped to the surface. Finding all these factors at the same time is somewhat difficult so any new ways to expand the possibilities of drilling in more areas are a great leap forward.
The idea behind AltaRock’s innovation is to alter the rock in order to allow more water flow, creating an enhanced geothermal system (EGS). By pumping cold water into the rock bellow the earth, the rock fractures and allow more water flow on a single well. This combined to a novel idea borrowed from the gas industry, which is to use a “plug” temporarily in a section of the well to increase hydraulic pressure.
The company has tried this technology in Oregon with very positive results, looking at potentially driving down the costs of obtaining the resource from the earth.
In the news piece, it is also mentioned that “AltaRock is also working with GE on an improved process for using hot water to generate electricity. It involves improving heat transfer from the hot water to a working fluid that drives a turbine. The approach could increase power output from a geothermal site still more.”