| By Clem Guttata
Back in April 2008, I wrote one of my first long diaries debunking clean coal myths: How Toxic is Clean Coal? A key point I wanted to get across then is "clean coal" technology only addresses problems with green house gases. It doesn't do anything to make all the other toxins in coal disappear. It concentrates them, making them potentially easier to responsibly treat or store. "Clean coal" technology only deals with one small part of the coal extraction, transport, and energy production process.
This month, a new study came out showing there's another reason why "clean coal" technology is anything but. We've always known it requires a whole more lot of energy as input to generate the same amount of energy as conventional coal technology. (The technical term for this is energy returned on energy invested: EROEI.) This new study is one of the first to quantify the impact of that additional energy production and consumption.
How clean is the energy required to generate "clean coal"?
Unfortunately, the energy required to generate coal-to-liquid fuels and then capture green house gases and then sequester the green house gases, creates a whole new set of problems.
Patrick Berry has the details in Science News:
As pollution bad guys go, carbon dioxide may be the media darling, but trying to capture it and lock it away could allow other repeat offenders to go free.
Power plant emissions that cause acid rain, water pollution and destruction of the ozone layer may actually be made worse by capturing the CO2 and pumping it deep underground, a new study reported online and in an upcoming International Journal of Greenhouse Gas Control suggests.
This increase of other emissions is largely because collecting and burying CO2 - a process called carbon sequestration - requires additional energy, new equipment and new chemical reactions at the plants. And using current technology, meeting all of these requirements releases extra pollutants.
"Other studies mostly just look at one aspect, the carbon capture," says study coauthor Joris Koornneef, an environmental scientist at Utrecht University in the Netherlands. "This is a first step in trying to quantify the [environmental] trade-offs."
Major infrastructure requirements are necessary to change this trade-off:
If the mining, transportation and other supporting technologies become greener in the future, the pollution penalty for carbon sequestration would be reduced, the researchers note.
Of course, those infrastructure investments further reduce the cost-effectiveness of "clean coal" compared to alternative fuels. |
