A Tale of Two Technologies

stack exhuast(slightly technical post)

Let me begin by posing a thought-exercise—if there were a way to use fossil fuel that didn’t release CO2 into the atmosphere, how would we feel about fossil fuel then? Extraction would still be problematic (mountain-top coal mining will always be repugnant), but there is no real question that there are still huge worldwide reserves of oil, gas, and coal. We’ve put a pretty good dent in what’s out there, but we aren’t going to run out quickly. In fact, there’s enough that environmentalists have been using the term “unburnable carbon” since about the time that Bill McKibben wrote his Rolling Stone article last year, “Global Warming’s Terrifying New Math,” that went viral. (Links below).

So let me tell you about two technologies. The first is CO2 sequestration, where CO2 is pumped underground and captured there. The Department of Energy began working with the Archer-Daniels Midland Company (ADM), a global food company, in 2008 to develop and implement a test project at their Decatur, Illinois, ethanol plant. The first part of this project has been running for about a year now, and is injecting 1,000 tons of pure CO2 a day (a by-product of making ethanol) into saline water underneath an impermeable rock layer that is 7,000 feet below the surface.  Once at depth, the CO2 combines with the salt water to make carbonic acid, and the tremendous pressures at this depth keep it locked up, even if the well were to fail for some reason, the carbon would stay there. Scientists and geologists have drilled multiple test wells in the area, and are monitoring the underground plume to ascertain whether or not the CO2 is doing what it is supposed to do underground. All indicators are that it is, and ADM is set to launch the second phase of this project, where additional wells will pump 3,000 more tons a day into the formation. (Your tax dollars at work—yay). The appropriate geology for this type of sequestration exists over wide swaths of the United States, and worldwide. Other CO2 injection wells have been operating on at smaller scales in Europe and the US since about the year 2000.

The second technology is coal-gasification. Burning coal in the traditional sense releases roughly twice the carbon that burning natural gas does (per BTU of heat output). But another way of deriving energy from coal is by gasification. It isn’t particularly new, a version of it was in wide use by the end of the 19th century to light streets with gaslight, and coal gas was piped in houses to be used as cooking and heating fuel. The DOE, beginning in the late 90s, has been running pilot projects with coal gasification to see if a cleaner way to burn coal could be developed. There are several types of plants, but the one I want to look at here is called an “Integrated Gasification Combined Cycle” plant, or IGCC. The DOE helped refit part of a traditional plant in the 90’s in Terre Haute, Indiana, at the Wabash River power generation facility, a 970 MWe facility. IGCC plants use pure oxygen to combust hydrogen, and then produce a side waste-stream that is nearly pure CO2. (Normal coal-fired plants produce a waste stream  where the CO2 is mixed with nitrogen and it is technically difficult to separate out). Environmental groups have opposed IGCC plants, because they still emit CO2, so in their eyes, they aren’t “clean coal”.

BUT—no one has done it in quite this fashion yet, but the CO2 stream from an IGCC plant can be married to the input side of sequestration wells like the ones ADM is using. Ka-ching—electricity from coal with very little or no CO2 emissions. In fact, with scrubbing, I’m thinking that the stacks would produce mostly nitrogen and water vapor.

So what’s the catch? Well, one catch is that it’s fairly new stuff and just hasn’t been put together in this fashion yet. (Though a somewhat similar operation has been underway in Germany since 2008 at Vattenfall’s Schwarze-Pumpe facility.) But a bigger catch is cost—it takes a fair chunk of the energy in the coal to run the IGCC and sequestration processes, so the power output from these types of coal/sequestration plants would be notably lower.  My rough guess would be that this combination would produce only about half the power output of a conventional coal-fired plant (if someone out there knows, send me a note). And this is why these CCS technologies (Carbon Capture and Storage) are going to be resisted by Big Coal—it will make their power less competitive. But the technologies could help us transition to renewable energy, and demanding that real “Clean Coal” be developed and used could be part of the path forward. In some ways the more expensive power from coal would function as a de facto carbon tax, and would push development of renewable sources and conservation/efficiency. A win-win scenario.

But there is a huge down-side to news like this—I’ll discuss it in tomorrow’s post.

“Global Warming’s Terrifying New Math”- http://www.rollingstone.com/politics/news/global-warmings-terrifying-new-math-20120719?page=2

News article about ADM project (much other info online)- http://herald-review.com/news/local/sequestration-project-at-adm-showing-early-success/article_49ae1d74-11aa-11e1-b018-001cc4c03286.html

DOE summary of Wabash River IGCC project- http://www.netl.doe.gov/technologies/coalpower/cctc/resources/pdfs/wabsh/netl1164.pdf

German Schwarze-Pumpe CSS plant-  http://www.vattenfall.com/en/ccs/schwarze-pumpe.htm

Image credit: hoboton / 123RF Stock Photo