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Geologists study energy source underground

Source: http://www.dispatch.com/content/stories/local/2011/08/28/geologists-study-energy-source-underground.html

Ohio wells could power heating, cooling systems

By  Dylan Tussel

The Columbus Dispatch Sunday August 28, 2011 6:13 AM

Tim Leftwich, left, of the Ohio Division of Geological Survey and Steven Shaffer of Battelle show rock core samples being tested to determine thermal conductivity. Underground temperatures and heat flow also are the subjects of study.


Geologists and energy experts say that using heat from the earth as a power source, and to heat and cool houses and businesses, might prove to be a clean-energy alternative for Ohio and other states.

To determine whether it will work, state geologists are using a $21.9 million grant from the U.S. Department of Energy to look for geothermal prospects throughout the country. Exploration efforts include studying underground temperatures, heat flow and thermal conductivity of rocks to determine whether geothermal energy is the right answer.

“Every state has potential,” said Lee Allison of the Arizona Geological Survey, who is principal investigator for the three-year study.

The first step is collecting data from oil and gas wells to look at temperature changes.

“The data ... will help find where geothermal potential is hidden,” Allison said. When underground temperatures are high enough, the energy can be used to run power plants.

Ohio’s data from 16,412 oil and gas wells doesn’t look that good. The deepest hole is 13,727 feet and has a bottom temperature of 190 degrees, said Mac Swinford of the Ohio Division of Geological Survey.

Drilling wells that deep would not be economically viable, Swinford said, adding that the temperature is still not high enough to produce steam to run a power plant.

The temperature below ground in Ohio increases between 1 and 2 degrees per 100 feet, compared with 2 to 4 degrees in many western states, said Tim Leftwich of the Ohio Division of Geological Survey.

However, geothermal-powered heating-and-cooling systems might be a viable option.

“Ground-source heat pumps are established in Ohio and will probably continue to thrive on their own,” Leftwich said.

Ohio State University is drilling 500 shallow wells to heat and cool five residence halls, said Scott Conlon, projects director for the school’s facilities-design and -construction department.

This ground-source method, which pipes water below ground to pick up Earth’s temperature and bring it back to the surface for heating and cooling, is efficient, Leftwich said. Water drawn from below ground is cooler than the surface temperature in the summer and warmer in the winter.

Still, rock cores also are being sent to Battelle to determine thermal conductivity. Researcher Steven Shaffer is testing the samples.

Insulators such as shale can conceal heat sources below them, Leftwich said.

Researchers also are preparing to explore developing geothermal heating-and-cooling systems using abandoned, flooded coal mines in eastern Ohio. This kind of system would use the water in the mines to heat and cool buildings. That project probably will begin next year.

“The easy way to get energy is just to burn something,” Leftwich said. “The new world requires a little more technology and thought processes.”

 

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