American Electric Power Corp. Alstrom technology will be used on part of AEP’s Mountaineer plant.

Fast-growing public concern over global warming has electricity generators focused on developing ways to capture and store carbon dioxide from coal-fired powerplants. A flurry of recent announcements of carbon-capture demonstration projects, combined with a  March 14 U.S. Energy Association conference and release of a Massachusetts Institute of Technology study, is pushing the topic to the forefront of the energy industry. Power sources are excited by the potential for progress, but caution that retrofitting plants with the technology may not be cost-effective.

Given the U.S. electricity industry’s heavy dependence on fossil fuels, rapid replacement by renewable energy is not possible, and many experts consider carbon capture and sequestration (CSS) the critical path to the industry’s near-term future (ENR 2/12 p. 36). The MIT study declares CCS “the critical enabling technology to help reduce CO2 emissions significantly while also allowing coal to meet the world’s pressing energy needs.”

The study prompted New Mexico Sen. Jeff Bingaman (D) to call for a March 22 hearing of the Energy and Natural Resources Committee about the findings. “This landmark report comes at a very opportune time,” Bingaman says. “Its recommendations will carry a lot of weight here in Congress.”

American Electric Power Co., Columbus, Ohio, plans to install carbon capture on two of its coal-fired powerplants and claims it will be the first commercial use of the technology at an existing plant. By 2008, AEP will install a carbon-capture system using a chilled ammonia process to capture carbon from the flue gas of a 30-MW portion of its 1,300-MW Mountaineer Plant in New Haven, W. Va.

WE Energies A 5-MW test of the chilled amonia process is being done in Wisconsin.

Bottled Up

The technology, from Alstom Power Inc., Windsor, Conn., chills flue gases, recovering large quantities of water for recycling, and deploys a CO2 absorber similar to those used in sulfur-dioxide scrubber systems. Alstom is installing a 5-MW pilot demonstration of the technology at We Energies’ 1,224-MW Pleasant Prairie, Wis., powerplant.

CO2 captured at the Mountaineer project will be injected into deep saline aquifers 9,000 ft below grade at the site for storage. The validation project, costing an estimated $50 million to $80 million, could capture up to 100,000 tonnes of CO2 annually.

Following the Mountaineer project, AEP plans a commercial-scale retrofit using the Alstom technology on one 450-MW coal-fired unit at its Northeastern Station, Oologah, Okla., selling the CO2 for enhanced oil recovery. That system is expected to cost between $250 million and $300 million and could be operational by 2011, company officials say.

AEP is trying other carbon-capture approaches as well. Bechtel and GE Energy in joint venture have contracts to engineer, procure and construct two 600-MW plants using integrated gasification combined-cycle technology in West Virginia and Ohio. In December 2006, AEP said construction would be delayed at least six months because initial cost estimates were higher than expected.

Under a memorandum of understanding, AEP and Babcock & Wilcox Co., Barberton, Ohio, plan to develop the first commercial validation of oxy-coal combustion technology at B&W’s 30-MW (thermal) Clean Environment Development Facility in Alliance, Ohio, starting with a pilot demonstration this summer. The oxy-coal process that will be used at the clean-air test facility uses pure oxygen for combustion of coal, eliminating nitrogen and creating a pure stream of CO2 for post-combustion capture.

The recent surge of interest in carbon capture and sequestration has not been lost on industry observers. A March 13 briefing on carbon sequestration held by the U.S. Energy Association in Washington, D.C., drew nearly four times the average turnout of past meetings on the subject, USEA officials say.

Still, the MIT study says that present government and private sector programs to develop large-scale demonstrations of the technology are inadequate. The study suggests that three U.S. and about 10 worldwide at-scale projects would be needed “to cover the range of likely accessible geologies for large-scale storage.” The study calls for more government support for future demonstration projects as well as research and development programs.

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Cost Concerns

The MIT group and the Electric Power Research Institute both tout the opportunities to install such technologies at new powerplants, but neither sees the likelihood of widespread retrofitting.

“You could conceivably retrofit existing plants but we don’t see that as a cost-effective option,” says John Novak, executive director for federal and industry affairs at EPRI. “It’s not as simple as bolting a piece of equipment on the back end of the plant. You have to redesign the whole plant.”

Even with a new plant design, carbon reduction could be tough to pencil out. EPRI estimates that such technologies could add between 50 and 80% to the cost of electricity compared to the cost of electricity at plants without capture systems.

But Bob Hilton, Alstom business development director, says his company remains committed to the opportunities. “The technology is completely retrofittable,” he says. “We have 350,000 MW of coal plants in the U.S. alone and to reach a reasonable goal in CO2 reduction, you have to reduce the existing fleet.”

The industry also continues to face unanswered regulatory and legal concerns about carbon once it is injected into geological formations. Julio Friedman, leader of the carbon management program at the Lawrence Livermore National Laboratory, Livermore, Calif., says several hurdles are impeding progress. “One front-burner issue is, ‘Who owns it?’” he says “Is it treated like a mineral lease or is it like water rights? Another question is, ‘How do you close a project?’ If you start a project and do everything you were supposed to do for 50 years, how do you close and decommission a site and walk away? They’re all open questions.”