Little sets environmentalists’ teeth on edge more than fracking. The technique was long-used with conventional vertical oil and gas wells to stimulate production. Hydraulic fluids were pumped down a well under high pressure to fracture a promising rock formation creating permeability that enabled gas or oil to flow more readily to the borehole.

It took on new life when the oil industry mastered drilling horizontal wells. With vertical wells, the borehole only traversed a few dozen feet of reservoir rock, but with horizontal wells it could access thousands of feet, potentially releasing much more oil or gas. It became possible to exploit shale rock that contained large amounts of hydrocarbons but had low permeability. Indeed, it rejuvenated a declining U.S. oil industry, restoring the country’s status as the world’s major producer.

Unfortunately, fracking is also an environmental nightmare. In addition to creating yet another source of greenhouse gas emissions, it uses huge amounts of water, threatening already imperilled fresh water sources. Fracking can also contaminate ground water while producing billions of gallons of toxic wastewater that must be safely disposed of. And then there’s the matter of earthquakes, reported in various fracking areas.

On the up side, there is another source of energy at depth amenable to fracking that is much more environmentally sound—geothermal energy. Sometimes, the Earth sends this energy to us at surface in the form of hot springs, geysers or lava, but mostly we have to go get it by drilling deep into the ground.

We must drill two parallel boreholes to reach a depth with temperatures of at least 170-200°C. We can then pump cold water down one borehole, let mother Earth heat it to high temperatures, and then flow it to surface up the other borehole to power steam turbines and create electricity (see the illustration). The water then cools and is recycled.

We must have sufficient permeability in the rock formation to allow the water to flow from one borehole to the other. This is where fracking enters the picture. Using the skills developed in the oil industry we fracture the rock between the boreholes. The result is an Enhanced Geothermal System (EGS).

In order to test tools and techniques to drill to the required depths and withstand the high temperatures involved, the U.S. Department of Energy is running a $300 million research project called Utah FORGE According to the project’s website, “The field laboratory comprises a large volume of hot crystalline granite between two deep directionally drilled wells at around 8000 feet … Partner institutions include universities, national labs, federal and state funded institutions, and private industry.” According to project manager Joseph Moore, “If we can extract even two percent of the energy between two and four miles depth, we would have more than 2,000 times the amount of energy [Americans] use yearly.”

Industry is already taking advantage of the project. Fervo Energy is producing power at a geothermal plant in Nevada slated to power Google data centres. Another project is being planned to send power to California utility customers.

As with all energy methods, there are environmental problems, starting with a need for large water volumes. This is mitigated by recycling the water. In addition, the process can use brackish water from underground aquifers. Earthquakes could still pose a problem although the pressures used are lower than in oil and gas wells.

The electricity cost is higher than wind or solar, however EGS has the potential to ramp up and down as needed whether or not the sun is shining or the wind blowing. No big batteries are required to keep power flowing around the clock.

EGS has promise for Alberta, a province with abundant knowledge of drilling and an abundant supply of people experienced in the business. An active geothermal industry would serve as a perfect transition for workers unemployed by the phase-out of fossil fuels. And then there are all those abandoned oil and gas wells. Some of them at least may yet serve a useful purpose. As may fracking.