"Kleen Coal" Debunked -- Another Filthy Lie from the Dirty P
"Kleen Coal" Debunked -- Another Filthy Lie from the Dirty Polluters
http://www.iht.com/articles/2007/02/21/business/coal.php
As U.S. companies plan new coal power plants, experts debate best way to make them cleaner. Doubts exist on main technologies for capturing carbon
WASHINGTON: Within the next few years, U.S. power companies are planning to build about 150 coal plants to meet growing electricity demand. Despite expectations that global warming rules are coming, none of them will be able to capture the thousands of tons of carbon dioxide each will spew into the atmosphere.
Environmentalists are worried, but they put their faith in a technology that gasifies the coal before burning because such plants are designed, they say, to be more adaptable to separating the carbon and storing it underground.
Most utility officials counter that the gasification approach is more expensive and less reliable, but they say not to worry because their tried-and-true method, known as pulverized coal, can also be equipped later with hardware to capture the global warming gas.
But now, influential technical experts are casting doubts on both approaches.
"The phrases 'capture ready' and 'capture capable' are somewhat controversial," said Revis James, the director of the energy technology assessment center at the Electric Power Research Institute in Palo Alto, California. Today in Business Japanese rate rise unlikely to interrupt flow of yen overseas As U.S. companies plan new coal power plants, experts debate best way to make them cleaner. Free Flow: Progress rides the rails of a New York subway line
"It's not like you just leave a footprint for some new equipment."
While James works for the companies that make electricity with coal, natural gas, nuclear reactors and renewable power sources, many experts outside the industry share similar concerns.
A major new study by faculty members at the Massachusetts Institute of Technology, scheduled for release soon, concludes in a draft version that it is not clear which technology - the so-called integrated gasification combined cycle or pulverized coal - would allow for the easiest carbon capture, because so much engineering work remains to be done.
"Other than recommending that new coal combustion units should be built with the highest efficiency that is economically justifiable, we do not believe that a clear preference for one technology or the other can be justified," the draft concludes. The MIT study said it was critical that the government "not fall into the trap of picking a technology 'winner.'"
The leader of the study, Ernest Moniz, a former assistant secretary of energy in the Clinton administration, was more blunt.
"Clearly in a lot of discussions, IGCC has been anointed as the solution," he said referring to integrated gasification combined cycle. Moniz made his comments at an environmental symposium organized by the Aspen Institute in Washington last fall. "We certainly don't agree with that."
Retrofitting either a gasification or pulverized coal power plant is not just a matter of adding new equipment and might be impractical, the experts say. Temperatures and pressures would be designed to be in one range for a plant that captured its carbon, and another if it merely produced electricity with minimum use of fuel. Less fuel means less carbon dioxide production.
Adding carbon capture later also has implications for power supply.
Early estimates are that carbon capture will require so much energy that it could reduce plant output by 10 percent to 30 percent.
Some experts say that the best choice may vary according to the type of coal used. Coal with high moisture content may be less suitable for gasification.
The technical assessment is certainly at odds with the hopes expressed by environmentalists. TXU, of Dallas, is planning a group of huge new coal plants of the pulverized variety. In Austin, Tom Smith, a researcher at Public Citizen, who is helping lead the opposition, said, "It's clear that coal gasification is by far preferable to building traditional pulverized coal plants."
Getting the carbon out of the gas stream before combustion must be easier, he said, because the post-combustion gases in a pulverized coal plant are 160 times larger.
Some utility executives agree. David Crane, the president and chief executive of NRG Energy, said that at some point, engineers may work out an economical way to capture carbon after combustion in a pulverized coal plant, but that this does not exist now.
Because carbon regulation is coming, he said, gasification plants will be needed.
"For the next generation, it's clear to me that rather than build a bunch of pulverized coal plants, with their 50- year life, the country is much better off if we go to IGCC, " he said. The company is planning such a plant in Tonawanda, New York.
Some environmentalists dispute the need for new coal plants, but unless there is very rapid progress soon in adopting energy efficiencies or developing the ability to extract and store huge amounts of wind and solar power at reasonable cost, more coal plants seem certain.
Compared with cleaner fossil fuels, like natural gas and oil, coal is cheaper and more widely available. So finding a way to capture the greenhouse gases from these plants is critical.
Engineers agree that it is easier to remove sulfur, mercury, particles and other conventional pollutants from plants that use gasification. But they are more expensive to build, and the industry has little experience with their reliability. Even the manufacturers concede this.
"It will work," Randy Zwirn, the chief executive of Siemens Power Generation, said of the ability to separate carbon from a gasified coal plant. "The question is, can it be done economically?"