Turning Bakken Oil Well Waste Water Into Clean Geothermal Power

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Geothermal Generators
Researchers stand at the site in North Dakota where geothermal generators are being installed. Source: University of North Dakota, Will Gosnold via Bloomberg

Oil fracking companies seeking to improve their image and pull in a little extra cash are turning their waste water into clean geothermal power.

For every barrel of oil produced from a well, there’s another seven of water, much of it boiling hot. Instead of letting it go to waste, some companies are planning to harness that heat to make electricity they can sell to the grid.

Companies such as Continental Resources Inc. and Hungary’s MOL Group are getting ready to test systems that pump scalding-hot water through equipment that uses the heat to turn electricity-generating turbines before forcing it back underground to coax out more crude.

Though the technology has yet to be applied broadly, early results are promising. And if widely adopted, the environmental and financial benefits could be significant. Drillers in the U.S. process 25 billion gallons (95 billion liters) of water annually, enough to generate as much electricity as three coal-fired plants running around the clock -- without carbon emissions.

“We can have distributed power throughout the oil patch,” said Will Gosnold, a researcher at the University of North Dakota who’s leading Continental Resources’ project well.

Geothermal power also holds out the promise of boosting frackers’ green credentials after years of criticism for being the industry’s worst polluters, says Lorne Stockman, research director at Oil Change International, an environmental organization that promotes non-fossil fuel energy.

“This is one way to make it look like the industry cares about the carbon issue,” he said. Even if steam generates less carbon than other oil field power sources, “if you’re in the business of oil and gas, you’re not part of the solution.”

Cheap Oil

Then there’s the money. With crude at less than $50 a barrel, every little bit can help lower costs. At projects like the one being tested by Continental Resources in North Dakota, a 250 kilowatt geothermal generator has the potential to contribute an extra $100,000 annually per well, according to estimates from the U.S. Energy Department.

That’s not big money and the $3.4 million cost to test the technology is still too much to apply to each of Continental’s hundreds of wells. Yet if the company can lower the costs of the technology, it will not only generate electricity it will also extend the economic life of wells, making them more profitable, said Greg Rowe, a production manager with Continental Resources.

University Projects

Continental Resources’s project began with the work of researchers at the University of North Dakota who were looking for ways to use geothermal resources from the thousands of wells being drilled in recent years, spurred on by new horizontal drilling technology. An existing relationship with the university triggered Continental Resources’s interest in the project.

The team took off-the-shelf geothermal generators and hooked them to pipes carrying boiling waste water. They’re set to flip the switch any day. When they do, large pumps will drive the steaming water through the generators housed in 40-foot (12-meter) containers, producing electricity that could either be used on site or hooked up to power lines and sold to the electricity grid.

Valuing Land

To take advantage of plentiful geothermal energy in oil wells, petroleum companies needs to change the way drilling and wells are planned to include the benefits of geothermal energy after most of the fossil fuels have been extracted, said Alison Thompson, chair of the Canadian Geothermal Energy Association and a former engineer at Suncor Energy Inc.

“We don’t value land here the same way that others do,” Thompson said, highlighting projects in Germany and Hungary where geothermal resources are considered part of the total opportunity to earn money from a well.

With $50 oil testing producers’ ability to make money, Gosnold is convinced that the idea will pay off if enough water can be pumped through the generators.

“The economics makes a lot of sense over the lifetime of a field,” he said.

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