Issue Date: April 2, 2007
Dealing with Carbon Dioxide from coal
IF "KING COAL" is to keep its top spot in an increasingly carbon-constrained world, chemists and engineers must quickly develop and test new technologies to capture and sequester carbon dioxide emitted by coal-fired power plants.
That's one of the primary conclusions of a new report by faculty at Massachusetts Institute of Technology. Also, at a March 20 hearing of a House Committee on Energy & Commerce subcommittee, Congress members heard the same point repeatedly in testimony by a half-dozen electric utility executives.
The premise of the MIT report, "The Future of Coal," is that the risk of global warming is real, and the U.S. and other governments must act to restrict CO2 and other greenhouse gas emissions. The cochairs of the 12-member MIT group are chemistry professor John M. Deutch and physics professor Ernest J. Moniz. Both are former high-ranking Department of Energy officials.
Deutch and Moniz both said they are convinced coal will continue to play an indispensable role in power generation because it is so cheap and abundant. They spoke at a conference organized by the Washington, D.C., economics think tank Resources for the Future on March 14 and at a hearing before the Senate Energy & Natural Resources Committee one week later. Coal-fired power plants currently produce about half of the U.S.'s electricity, and coal plants are just shy of matching motor vehicles for the dubious honor of being the largest source of U.S. CO2 emissions.
That's a context that makes it imperative to find ways of capturing CO2 from coal-plant emissions and sequestering it in deep geologic reserves. Existing technologies are promising, but they are expensive and are commercially untried.
In order to move ahead with development and implementation of new practical and reliable technologies, Moniz and Deutch said, there is a price to pay.
"A significant charge for carbon emissions is needed for a market to develop technologies that could lead to stabilizing carbon over the next century," Deutch said during his Senate testimony. The charge, he said, will open the door for new CO2 capture and sequestration technologies and will provide impetus to develop alternative non-carbon-based energy sources. The price should be in the range of $25 to $30 per ton of CO2 emitted, Deutch said, estimating that this price may lead to a 20 to 25% increase in the retail cost of electricity.
The payoff from ushering in new technologies would be a flattening of CO2 emissions by 2050. The economic model that the MIT analysts used assumed the tax began in 2015 and increased by 4% per year; the model predicted global coal use would continue to grow despite the emissions tax.
With lower pricing for CO2 emissions—say $7.00 per ton of emissions—new technologies would be stalled for an additional 25 years, the report predicts.
Along with a stiff carbon tax, Deutch and Moniz stressed, the government must ramp up and focus its coal-based R&D program. Moniz urged DOE to increase coal-based research funding to $800 million per year for the next 10 years, more than twice the 2007 level of $330 million and nearly twice the Administration's 2008 proposal for $427 million. Deutch and Moniz also recommended that no federal R&D support be offered for coal-based energy technologies that do not include carbon capture and sequestration.
They argued that there are currently no operating carbon capture and sequestration demonstration programs sufficiently developed and monitored to lead to commercialization.
ALTHOUGH THEY applaud DOE's recently begun FutureGen demonstration project, Deutch and Moniz urged the department to speed it up, streamline it, and in Moniz's words, "have fewer chefs in the kitchen." FutureGen is a $1 billion integrated gasification combined cycle (IGCC) project. The plant will produce hydrogen, generate 275 MW of electricity, and capture CO2. It is based on a gasification technology commonly used in the chemical industry, but it will generate electricity and capture CO2 for sequestration underground.
DOE is considering four sites for FutureGen-two in Texas and two in Illinois. All are located near electrical transmission lines and near geological formations suitable for underground CO2 injection. The plant is planned for operation by 2012.
Moniz and Deutch also want DOE to broaden its carbon-capture-technology demonstration programs to include a wider range of non-IGCC, pulverized coal plants. They warned that DOE may be emphasizing IGCC too heavily in this early part of the R&D process.
DOE also should enlarge its carbon sequestration programs, the MIT duo said. The report they oversaw supports three large-scale global sequestration programs that are operating today. Although they say these plants are sufficient in size to demonstrate possible commercialization, they also note the facilities are insufficiently monitored and lack instrumentation needed to actually prove the technology.
The projects are the Weyburn, in Canada; Sleipner, in the North Sea; and In Salah, in Algeria. All of the projects are injecting into the ground nearly 1 million tons of CO2 per year. Sleipner and In Salah are injecting the gas into deep saline formations that, the report says, offer the greatest promise to store enough CO2 to make a dent in global emissions.
Weyburn, however, is injecting CO2 for the purpose of recovering oil, not storing CO2. These oil-recovery projects, according to the report, are inadequate in size for large-scale sequestration of CO2. In addition, the report says, geological formations tapped for oil may have been disrupted too much to successfully host massive amounts of CO2.
The report urges the U.S. to fund five new large-scale CO2 sequestration projects.
The amount of CO2 that needs to be injected to make an impact on the levels of greenhouse gases in the air is mind-boggling. Although the 1 million tons per year injected underground by the three demonstration plants is large enough to serve as a proof of principle, the report notes that this level works out to about one-third of the CO2 generated annually by a single 500-MW coal-fired power plant. Moreover, the report says, the U.S. has the equivalent of more than 500 plants of that size. The U.S. alone produces about 1.5 billion tons of CO2 per year from coal plants.
The picture gets worse when seen in a global perspective. China, the report notes, is building the equivalent of two 500-MW coal-fired power plants per week and is close to matching the U.S. in CO2 emissions.
Deutch and Moniz stress the importance of moving quickly with new large capture and sequestration technologies in the U.S., but they warn that the efforts to reduce CO2 emissions must be done globally or any U.S. efforts and investments will be wasted. But, they say, U.S. leadership in CO2 capture and sequestration is paramount before similar technologies will be applied by China and India, which lack incentives to fund new carbon-limiting technologies as they struggle to develop their economies.
The MIT report also notes that, along with showing potential commercial success, a program for developing new CO2 management technologies should include a regulatory framework. Without regulation, the public won't accept sequestration, and investors are unlikely to provide capital for new and more expensive projects, the report contends.
What utilities should do now in this era of uncertainty is a difficult question, and the report provides little guidance. This near-term dilemma was taken up by a half-dozen utility chief executive officers testifying at the hearing before the House Energy & Commerce Committee.
The CEOs backed greater federal investments in R&D for capture and sequestration, and about half of them supported a CO2 cap-and-trade program. But they all said implementation of a CO2 tax or cap-and-trade system should await a technological solution that will allow for CO2 sequestration. Until a proven technology is in hand, they note, financiers will be unlikely to support building new plants.
SEVERAL UTILITIES, such as American Electric Power (AEP), Duke Energy, and more recently TXU, are taking early steps and have announced long-range plans to build IGCC projects that include CO2 capture and sequestration.
AEP may be furthest along, according to testimony by Michael G. Morris, AEP chairman, president, and CEO. Along with plans to construct two IGCC plants during the next decade or so, AEP intends to install CO2 capture technologies at two existing pulverized-coal plants.
Next year, AEP's Mountaineer Plant, in New Haven, W.Va., will begin capturing up to 100,000 metric tons of CO2 annually to validate a capture and sequestration technology. The CO2 will be placed in deep saline aquifers near the site. And by 2011 the company plans to ramp up this system and use it at a 450-MW unit in Oologah, Okla. Plans are for a commercial-scale system to capture 1.5 million tons of CO2 annually and sell it for use in an oil-recovery operation near the site. Both plants are currently operating pulverized- coal plants that will be retrofitted to include CO2 capture.
The pressure to get moving on capturing and sequestering CO2 is likely to greatly increase. Studies by DOE and industry have predicted more than 100 new coal-fired power plants will be needed in the U.S. to satisfy demand for electricity during the next 20 years. However, with more than a half-dozen climate-change bills now pending before Congress, congressional climate-change hearings being held almost daily, and state legislatures and utility boards looking harder at the cost and environmental impact of coal plants, the path ahead is far from clear.
- Chemical & Engineering News
- ISSN 0009-2347
- Copyright © American Chemical Society