Monday, December 12, 2005

State clean coal plans

A friend asked me about a article summarizing some state clean coal plans (Pa. leads push for new coal plants) and I thought I might as well post my thoughts. He specifically asked about the environmental impact of the Rendell plan.

Note that I haven't read all the specifics of the Rendell plan or the other plans - these are general reactions.

Figuring out the environmental impact is a little difficult because the article mixes together a few different technologies and initiatives. There are two different technologies discussed: coal gasification and coal liquifaction. Coal gasification is part of a coal-combustion technology called IGCC (integrated gasification combined cycle). IGCC is currently used at two electric generating
plants in the U.S. IGCC is recognized as being a cleaner way to burn coal but it is more expensive that pulverized coal combustion. IGCC allows the user to separate many of the pollutants before combustion, resulting in fewer emissions. It is also easier to separate out the CO2 from IGCC - meaning that the CO2 is easier to capture and store in geologic formations (in a future where that is routine).

Coal gasification is the subject of the Nov 28 Rendell plan. Generally speaking, retiring old power plants and building IGCC plants is a good thing - assuming we are going to be burning coal for decades to come. However, Rendell is asking for a delay in meeting the pollution reduction requirements of CAIR - that is where it gets fuzzy. An extension for plants in PA could muddle the entire plan.

Coal liquifaction is the process of turning coal into oil or diesel fuel. That process is also expensive but has similar benefits. If you can get the pollutants out before combustion it is easier to control them. Also, if (or when) capture and geologic storage becomes viable, some CO2 from the process could be captured. However, you are still burning the fuel in cars - so CO2 is still going to be coming out of the tailpipe - uncaptured.

I would have to see the data but I have heard NGO folks contradict what the NRDC person said about the quality of the fuel from this process. The diesel from this process may actually be cleaner burning than the diesel products sold at gas stations.

Final note, the other NRDC comment is about the environmental impacts of mining coal. That is a different ball of wax and certainly needs to be addressed. Note that the liquifaction process in PA is converting coal waste - already mined stuff that is (quite literally) just sitting around.


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