In Utah, researchers are trying to unlock Earth’s heat and make geothermal energy a reality

The day began inauspiciously for John McLennan as he tried to break the curse haunting a 45 year quest to get abundant energy from deep within Earth.

A researcher with a sore back was recovering in a hotel after an accident. There were reports that the sensors were malfunctioning. Repairs were delayed by gale-force winds that whipped the sagebrush covered hills and buffeted a drilling rig that rose 50 meters from the desert. Each day the workers burned an additional 350,000 dollars.

McLennan was ready to take a critical step in the advancement of the FORGE project shortly before sunset. If FORGE succeeds, it will show how to transform dry, intensely hot rock found belowground all over the world into a major renewable source of electricity.

McLennan, eyes baggy with fatigue and wearing the same brown sweater as the day before, faced five computer screens in the trailer because of the bad weather. A giant of a man in a white hard hat looked in as the trailer door opened. I'm ready for you to leave?

Mclennan said yes. "We're prepared."

With that, powerful pumps nearby sprang to life and began pushing thousands of liters of water down the hole.

The idea of generating electricity from Earth's internal heat is easy to understand. The heat leaking out of the Sun comes from the temperatures in the planet's core. molten lava, steaming vent, and hot springs are some of the places where this energy comes from. More often, it is trapped in the deepest parts of the earth.

There's a lot of it. More than 5000 gigawatts of electricity could be produced from heat in rock in the United States alone. It is five times the total generated by the power plants in the U.S. It doesn't burn fossil fuels, isn't imported, and can run around the clock, which makes it attractive.

It has been hard to tap that heat. The volcanically active nation of Iceland sucks hot water to heat buildings. In most places the rock doesn't have enough water or cracks to move heat to the surface. Engineers have tried for decades to get heat from this rock, which can reach temperatures of more than 250C. According to the International Energy Agency, little has changed from 1990 in terms of the amount of electricity provided.

New technologies developed by the oil and gas industry have given rise to new hope for renewable energy. It is hoped that the same methods that have boosted fossil fuel production in the US can be used to efficiently and safely extract energy from hot, dry rock. Government agencies and private companies are pouring hundreds of millions of dollars into the approach, which has had setbacks. FORGE, located on a remote patch of land in southeastern Utah, has become a closely watched effort to demonstrate and fine tune EGS technologies.

The leader of FORGE says thatgeothermal isn't going to work if we can't makeEGS work. The bottom line is what I mean.

There is a sense of familiarity for McLennan. In 1983, when he was an engineer at an oilfield company, he worked with scientists from the Department of Energy's Los Alamos National Laboratory on a project to exploit hot, dry rock in New Mexico. The scientists wanted to create artificial hot springs by injecting water into deep fissures and then releasing the heated water into a nearby exit well. The injected water didn't reappear, and the water disappeared into undetected cracks.

McLennan was disappointed. It was a lot.

The same thing happened decades later to the Cooper Basin Geothermal plant. The project shut down after just 5 years after water flowed into a fault.

In some places, EGS projects had more dramatic failures, as high-pressure water injected into the ground caused existing faults to slip. The project was shut down in 2006 after earthquakes. A magnitude 5.5 earthquake killed one person and caused more than $75 million in damage in Pohang, South Korea, eleven years ago. It was traced to a new EGS project where operators had injected fluid at high pressures near a previously unknown fault.

It is a challenge to drill into hot, dry rock. Equipment designed for the softer, cooler rock often found in oil fields fails in the extreme temperatures of hot, hard metamorphic rocks.

Three EGS power plants are located near the borders of France and Germany. They are able to power 9000 homes by generating less than 11 megawatts.

Jamie Beard, an attorney and executive director of the new nonprofit Project Inner Space, says that EGS has always been fraught with technological challenges. She says thatEGS in its pure form is difficult.

New techniques have arisen from the oil and gas industry. Engineers were taught to drill horizontally. They are able to create wells that can look like roller coaster routes. It is possible to release oil and gas from veins of rock as small as 5 meters. The advances have made investors and governments look at EGS differently.

1 In EGS, a cold fluid such as water is injected into wells deep enough to reach hot, dry rock, often kilometers down. 2 Water is heated as it flows into cracks in the rock. In EGS, high-pressure fluids are used to create new fractures or enlarge existing ones, a technique much like the fracking used in the oil and gas industry. 3 Hot water is pumped to the surface via exit wells drilled not far from the injection well. The water turns to steam as the pressure drops closer to the surface. 4 The steam is directed to turbines that generate electricity. Most of the water is reused and continues the cycle. 5 EGS-like techniques can also be used to create water that’s not hot enough to efficiently generate electricity. But the artificial hot springs can be used to warm homes and commercial buildings, and drive a variety of industrial processes. C. Bickel/Science

More than two dozen geothermal companies have emerged in the United States in the last decade, according to Beard. In Germany, the Helmholtz Association of German Research Centers announced in June that it is putting 35 million into a new underground laboratory dedicated to geothermal research. The DOE is spending $84 million on four EGS pilot projects. They will be studying the best ways to extract heat from different types of rock in the US.

The results of FORGE were used to create a laboratory for honing EGS tools. The University of Utah and partners won funding from the DOE to build a facility near a small railroad town in Utah.

The vegetation in the valley is so thin that much of the history of the area is not known. Moore has been reading that book for more than 40 years. He stood next to a cliff that ran north to south along a small hill. He said that this is a fundamental boundary.

There are two different worlds that the wall divides. The Mineral Mountains have rounded peaks speckled with granite outcroppings and juniper trees. The top of a long-dead volcano is marked by a flat-topped mountain devoid of granite.

There is hot water close to the surface between the cliffs and the mountains. A squat, brown building tucked into the foothills has a 38 megawatt conventional geothermal power plant. There is a hot spring next to the ruins of a resort built in the 1800s. It used to be the world's richest silver deposit. About 1600 years ago, hot springs saturated withsilica spilled to the surface, leaving behind rocks candy-striped in yellow, red, and white.

The ground is blocked by an underground wall of solid granite that reaches a temperature of 235C. A metal skeleton dwarfs the trucks and one-story buildings that surround it.

A similar rig was used to drill an injection well. 3.3 kilometers is the length of the completed shaft. Features that are standard in frack operations are included in the well. The FORGE shaft is designed to intersect with natural stresses in the rock in a way that would allow engineers to amplify tiny existing fractured rocks.

The rock is 1.7 billion years old. The metal drill bits couldn't cut through the stone and the younger granite advanced just 3 meters per hour and often broke. Synthetic diamonds were used for the first time for Geothermal drilling in granite. The bits sliced through the rock 10 times faster and are definitely a breakthrough. The result of the project is very large.

The FOR GE well is lined with steel. It is easier to use a special gasket to seal off sections of pipe in which operators blow up small explosives, shattering the pipe and exposing the surrounding rocks. It's another novelty in EGS.

The piecemeal approach could help the EGS avoid drilling in sensitive areas that could cause earthquakes. He cautions that spotting problem faults in hard basement rock is not easy.

The gasket used in oil and gas wells has crumbled due to the high heat of the granite. The sensors are essential to track the operation. The team has been testing high-temperature gasket and new monitoring tools to see if they work.

Other technologies are being developed by universities, government labs, and companies. One technique for targeting specific regions of rock is to use a small device that looks like a skateboard to drive deep into the well to open and close the windows. tool development is crucial to moving EGS into the mainstream.

McLennan and the FORGE team were ready to see if they could pump enough water into the deepest part of the well, under enough pressure, to enlarge tiny cracks or create new ones in pockets of granite.

The schedule was thrown into disarray due to the equipment malfunction. McLennan was sitting in front of his computer screens, ready to guide a plane in for a landing.

The voices were loud over the radios. Kevin England gave short commands beside him.

The row of water tanks were large enough to fit a school bus. The roar of engines filled the air as the trucks moved water to the well.

The water was flooding into the hole and the pressure was hitting the last 60 meters of rock, leaving no steel shell. The engineers hoped that by creating a dense cloud of fractured nerves, they would be able to insert needles into them.

The gradual rise in water pressure was marked by a red line. The line bounced around a pressure of about 28 megapascals, more than 250 times the atmospheric pressure. It was good to hear that the rock was giving way. McLennan said they were getting some action. It's nice.

The signals continued to be positive. McLennan appeared at ease for the first time in a long time. He said this is gorgeous. Then it stops and starts again.

It was difficult to know what was going on. Jim Rutledge was at a nearby screen. Small earthquakes were marked by clusters of black dots on a grid half a kilometer away. There was no cause for alarm because the tremors were a sign that the process was going well. A big cloud surrounds us.

At 77 minutes in, the volume of water pouring down the well had grown to 50 barrels per minute, which some had predicted the team wouldn't reach.

Moore said let's go to 60.

"Let's stick to the plan," McLennan said. The pumps went quiet.

The day after the April test, Moore and McLennan were happy. The FORGE team is sifting through the data collected during that test as well as two fracks at locations higher up in the same well. The next steps will be shaped by what they learned.

A 3D map of the small earthquakes that occurred during the tests will help them decide where to drill a second well. They will pump water down the first hole in order to see what happens when the second hole is filled.

ForGE is watched closely by others. Plans for an EGS project in Switzerland are being led by a man. He hopes FORGE will point the way to reduce the risk of earthquakes by executing smaller fracks.

Others are eager to see whether FORGE can identify ways to make EGS more commercially attractive by solving problems that are scaring off would-be investors, such as time-Consuming drilling, broken equipment, and uncertainty over whether a well can produce hot water.

The Geothermal Technologies Office is focused on taking away the risk from the community.

Other strategies have more immediate commercial promise. They should be called EGS 2. Beard believes that targeting softer, slightly cooler rocks at deeper depths is a good idea. The approach relies on engineered hot springs. Beard says that drillers have gained expertise from boring tens of thousands of wells into the formations.

One company is doing that The Houston-based company was founded in 2020 by scientists and executives from the oil giant Shell. Liquid carbon dioxide has a lower boiling point. The steam would be used to drive the turbines.

A long time EGS advocate is trying a different approach. The lead author of a 2006 DOE report about EGS was a chemical engineer from Cornell University. He is in charge of a program that started this summer to drill a test well in New York state. Hot water would be enough to heat all the university's buildings if rock temperatures were to top out at 100C. Lower temperatures can be found in a lot of places. He says it doesn't have to be warm. The feature of usingcooler rock directly for heating is gorgeous.

The hot, dry rock just a few kilometers below is believed to hold enough heat to power a city the size of Salt Lake City. The facility might never be able to light a single bulb because it is a testbed.

It doesn't bother Moore. Moore stood on a dirt road a short distance from the drill rig and said that the purpose of things like this was not to solve all the problems. The private sector can see its viability if FORGE can takeEGS to the point where it can be seen.