...of the energy division at Kansas City-based Burns & McDonnell. Supercritical PC requires "tighter control with operating temperature in the boiler," he says. "Were about the only place in the world still using subcritical."
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| On Deck. Typical B&W 750-MW spiral-wound universal pressure boiler is similar in concept to the supercritical addition at Weston. |
Today, two supercritical plants are under construction and a third is expected to begin next year (see related story). CFB boilers have been increasingly specified in recent years (ENR 12/2/02 p. 39). And three teams of engineer-constructors and equipment makers are developing opportunities to construct IGCC plants in the U.S. In September, the GE Energy and Bechtel Power Corp. team began front-end engineering design for a $1.2-billion, 629-MW IGCC project in Ohio for American Electric Power Co., Columbus (ENR 10/17 p. 9).
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| Wisconsin Public Service Corp.s Weston powerplant unit 4, one of only two supercritical pulverized-coal plants in construction in the U.S., is expected to be followed by others soon. (Photo courtesy of Babcock & Wilcox Co.) |
With an emission profile close to a natural-gas combined-cycle plants, IGCC is the apple of the clean-coal power markets eye. Its most serious drawback is its cost. An analysis early this year by the Electric Power Research Institute (EPRI), Palo Alto, Calif., found that electricity from the next few IGCC plants will cost about 15 to 20% more than electricity from conventional pulverized coal plants. The high cost and relatively untested technology were cited by the Public Service Commission of Wisconsin in 2003 in rejecting Wisconsin Energy Corp.s plan to construct a gasification plant.
Capital costs for gasification plants run in the range of $1,400 to $1,600 per kW, says Scott Klara, deputy director of the Office of Coal and Power Systems at Pittsburgh-based National Energy Technology Laboratory (NETL). That is higher than $1,200 to $1,400 for supercritical technology and well above the $1,100 to $1,300 per kW for subcritical.
High capital cost and technology risk were confirmed as the largest perceived risks of IGCC in a study of owners, regulators, financial institutions and vendors by Deloitte Financial Advisory Services LLC this year for DOEs Office of Fossil Energy. But the report also noted that uncertainty about regulation of carbon makes owners reluctant to commit to a technology for which carbon capture is a major selling point.
Of the major clean coal technologies, circulating fluidized-bed combustion is the most proven. But "CFB will be a real niche market," with 3,000 to 3,500 MW installed in the next 10 years, says Kowalik. Its niche is the industrial market, where it will displace gas boilers, he says.
Support
Advanced coal plants now in the pipeline owe a lot to government programs promoting research, development and deployment. The Energy Policy Act of 2005, signed in August, authorized DOE to spend $200 million per year through 2014 to co-fund clean coal projects with industry. At least 70% of the funds are earmarked for technologies related to coal gasification. The act also authorized loans and loan guarantees for Clean Power Projects, again mostly focused on gasification technology.
This comes on top of longstanding programs such as Vision 21, whose goal is to develop a fossil-fuel plant that will co-produce multiple commercial products while achieving the ultimate in fuel-to-power efficiency and environmental cleanliness, say DOE officials.
In 2004, EPRI launched CoalFleet for Tomorrow, a joint effort of 17 generation companies and Fluor Corp., Aliso Viejo, Calif., to accelerate deployment of advanced coal technology and develop options for managing powerplant CO2 emissions. In its first year, at the request of its members, CoalFleet has concentrated on IGCC technology, "but it has always been our contention that more than one option is needed for advanced coal, including options for postcombustion CO2 capture and storage," says Stuart Dalton, EPRI director of generation. CoalFleet now has 45 members from eight countries. 
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CoalFleet has met its goals for the first year, including beginning preparation of broad plant design guidelines for IGCC. Now, while refining the guidelines, "we will start a parallel effort in combustion to accelerate deployment of more advanced combustion options, such as high-temperature, high-efficiency ultrasupercritical coal plants and supercritical fluidized-bed plants," says Dalton.
"The next wave of coal units is going to be supercritical technology," says John R. Black, Babcock & Wilcox manager of business development. NETLs Klara agrees that supercritical is ready to take off and foresees commercialization of ultrasupercritical technology beyond 2010. The tipping point for commercialization of gasification will come after 2015, he predicts. By then, "clean coal" may become a term even the most adamant environmental activist can embrace.
