Researchers at the University of North Dakota believe geothermal energy production should be a significant part of America's future energy portfolio.

But to get the industry off the ground, proponents are looking to an industry not normally associated with renewable energy -- gas and oil drillers.

"Oil- and gas-producing sedimentary basins in Colorado, Illinois, Michigan, and North Dakota contain formation waters of a temperature that is adequate for geothermal power production," researchers wrote in their new study on the subject, published this week in the journal Geosphere.

Geothermal energy requires heat, and natural sources of heat lie deep within the ground. Gas and oil drillers have already built the infrastructure to access deep-lying natural resources. Of course, gas and oil drillers want gas and oil, not heat. But in their quest for gas and oil, they get heat nonetheless.

As part of their study, researchers at North Dakota plotted temperature gradients in basins that are currently being or have been drilled by oil and gas extractors. The study highlights the regions where geothermal operations would be most feasible.

"Denver-Julesberg Basin (which spans Wyoming, Nebraska, and Colorado, and has a surface area of approx. 155,000 square kilometers) has the highest capacity for large-scale, economically feasible geothermal power production," the researchers wrote in a press release.

Geothermal operations could re-purpose infrastructure no longer used by oil and gas drillers, or ongoing drilling operations could adopt geothermal technology as a side project. For every barrel of oil or gas extracted, drillers generate seven barrels of hot water.

That water could be used to power geothermal turbines and produce extra electricity -- electricity that could be sold to help the bottom line and lessen the carbon footprint of fossil fuel companies.

Whether geothermal proponents go it alone, or in tandem with drillers, the technology's expense remains potentially problematic. But by identifying the hottest and easiest places to drill, researchers hope they can get a little closer to spurring action in the geothermal industry.

"This shows locations where temperature will be highest at the shallowest depths in regions of soft sediments, refining the map creation process," researchers said of their work.