Stories tagged geophysics

Oct
07
2010

What if I told you University of Minnesota geology and geophysics professor, Martin Saar, says geothermal energy can be made even greener through carbon sequestration?!

You’d probably say, “Huh?? Hold on, what is geothermal energy anyway, and how does it work?”

Geothermal is heat from deep inside the earth. Because heat is a form of energy, it can be captured and used to heat buildings or make electricity. There are three basic ways geothermal power plants work:

  1. Dry steam plants: Uses high-pressured hot steam to turn generator turbines. Think “steam to turbines.”
  2. Flash steam plants: Uses high-pressure hot water to create steam to turn generator turbines. Think “water to steam to turbines.”
  3. Binary cycle power plants: Uses high-pressure hot water to heat another liquid, which then turns to steam and turns the generator turbines. Think “water to other liquid to steam to turbines.”

(Click here for great diagrams of each of these geothermal energy production methods.)

“And what about carbon sequestration too? What’s that and how does it work?”
Carbon Sequestration: This nifty diagram illustrates both terrestrial and geologic carbon sequestration pathways.  Bonus!
Carbon Sequestration: This nifty diagram illustrates both terrestrial and geologic carbon sequestration pathways. Bonus!Courtesy Department of Energy

Carbon sequestration includes carbon (usually in the form of carbon dioxide, CO2) capture, separation, transportation, and storage or reuse. Plants, which “breathe” CO2, naturally sequester carbon, but people have found ways to do it artificially too. When fossil fuels are burned to power your car or heat your home, they emit CO2, a greenhouse gas partially responsible for global climate change. It is possible to capture those emissions, separate the bad CO2, and transport it somewhere for storage or beneficial reuse. CO2 can be stored in under the Earth’s surface or, according to Martin Saar’s research, used in geothermal energy production.

Alright. We’re back to Professor Saar’s research. Ready to know just how he plans to sequester carbon in geothermal energy production?

It’s a simple idea, really, now that you know about geothermal energy and carbon sequestration. Prof. Saar says geothermal energy can be made even greener by replacing water with CO2 as the medium carrying heat from deep within the earth to the surface for electricity generation. In this way, waste CO2 can be sequestered and put to beneficial use! As a bonus, CO2 is even more efficient than water at transferring heat.

But don’t take my word for it. Come hear Professor Martin Saar’s lecture, CO2 – Use It Or Lose It!, yourself during the Institute on the Environment’s Frontiers on the Environment lecture series, Wednesday, October 27, 2010 from noon-1pm.

Frontiers in the Environment is free and open to the public with no registration required! The lectures are held in the Institute on the Environment’s Seminar Room (Rm. 380) of the Vocational-Technical Education Building on the St. Paul campus (map).