Stories tagged carbon sequestration

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).

Nov
08
2009

Cleaner coal: The Mountaineer Power Plant is the first in the world to capture some of the carbon dioxide it emits from burning 3.5 million tons of coal yearly and sequester it two and a half kilometers underground.
Cleaner coal: The Mountaineer Power Plant is the first in the world to capture some of the carbon dioxide it emits from burning 3.5 million tons of coal yearly and sequester it two and a half kilometers underground.Courtesy rmcgervey

Carbon dioxide removed from power plant exhaust and pumped underground

In addition to other environmental technology add-ons that strip out the fly ash, sulfur dioxide and nitrogen oxides, the Mountaineer Power Plant in West Virginia now also uses a carbon-capture unit built by Alstom. Dubbed the "chilled ammonia" process, baker's ammonia is used to strip carbon dioxide from the cooled flue gas and then, by reheating the resulting ammonium bicarbonate, captures that carbon dioxide, compresses it into a liquid, and

pumps it 2,375 meters straight down into the Rose Run sandstone, a 35-meter-thick layer with a nine-meter-thick band of porous rock suitable for storage. (or...) into Copper Ridge dolomite, which has much thinner strata for possible storage, more than 2,450 meters down. Thick bands of shale and limestone that lie on top ensure that the carbon dioxide does not escape back to the surface. Scientific American

Only 1.5% but first in the world

Only about 1.5 percent of the carbon dioxide billowing from its stack is being captured now. Scaling up the process to capture 20% of the CO2 will cost at least $700 million. The removal of carbon dioxide will add abouts 4 cents more to the current cost of Mountaineer electricity (roughly 5 cents per kWh). This chilled-ammonia technology should be available commercially by 2015.

Learn more:
Slide show of Mountaineer Power carbon sequestering technology.
First Look at Carbon Capture and Storage in a West Virginia Coal-Fired Power Plant Scientific American

Feb
24
2008

Grand Challenges for Engineering in the 21st Century

Want to know what to do with your life. A diverse committee of experts from around the world, at the request of the U.S. National Science Foundation, identified 14 challenges that, if met, would improve how we live.

Here is their list in no particular order. You can learn more about each challenge by clicking on it.

You can vote for which is most important

The committee decided not to rank the challenges. NAE is offering the public an opportunity to vote on which one they think is most important and to provide comments at the Engineering Challenges website