‘Clean’ Electricity: Coal Emerging From Black Cloud
Towering 15 stories above the swamp it shares with a colony of alligators, Polk Power Station may be the best available test of the Bush administration’s claim that one of America’s most abundant energy sources can clean up its act.
When a task force headed by Vice President Dick Cheney unveils a comprehensive national energy policy later this month, “clean coal” power plants like Polk are expected to play a key role in meeting future demands for electricity.
Experts say the nation’s generating capacity needs to grow 45% by 2020. Coal-fired plants already produce half of the nation’s electricity. Although coal’s share is expected to decline over time, its advocates say other energy sources will never be plentiful enough to eliminate coal from the mix entirely.
But environmentalists predict the country will pay a significant price--in the form of more smog, acid rain and global warming--if it rushes to embrace a fuel that will always be dirtier than just about any alternative energy source.
To some extent, both sides are right.
An hour’s drive southeast of Tampa, Polk Power Station is one of only two working examples in the U.S. of electricity produced by a process called combined-cycle integrated gasification. It is the most advanced technology to emerge from the Energy Department’s 16-year-old “clean coal” program.
Instead of burning raw coal like most power plants, the Polk plant pressure-cooks it, creating a gas that fires the turbines of Polk’s big electrical generator.
Tampa Electric Co. and the federal government have sunk 12 years and $650 million into the venture, or about three times the cost of an equivalent natural gas plant.
The results, when compared with a typical coal-fired plant equipped with modern pollution control devices, are significant: 85% less nitrogen oxide, the key component of smog, and 32% less sulfur dioxide, the source of acid rain, according to the utility.
Pollution Is Still a Problem
Yet Polk still sends more of these pollutants into the air than the natural gas-fired plant next to it; nitrogen oxide emissions are 20 times higher, and, because natural gas-fired plants emit virtually no sulfur, its sulfur emissions are more than 100 times higher.
Of even greater concern to environmentalists, Polk emits almost as much carbon dioxide as a traditional coal-fired generator, and more than twice as much per unit of energy as the natural gas plant. Although carbon dioxide is not regulated as a pollutant, experts believe it contributes to global climate change. Power plants account for about a third of the U.S.’ carbon dioxide emissions.
“Clean coal,” environmentalists are fond of saying, is an oxymoron.
David Pai, president of Forest Wheeler Development, a global power company that is bullish on gasification, predicts that gasifiers such as Polk will replace some of the nation’s oldest and dirtiest coal plants, many of which have not been required to install pollution controls. Over time, he expects it to become the technology of choice in many areas of the country.
“I would love all my plants to be solar or wind, but the reality is these so-called renewables are not enough to supply what we need,” Pai said. “And the natural gas supply is limited, and the infrastructure is not available. If it were available, we wouldn’t be pushing coal at all.”
But many environmentalists object to the government’s efforts to burnish coal’s image. They’re especially outraged by the prospect of more government subsidies for the technology. “I think it’s a disastrous way to go; it’s looking backward instead of forward, and it ignores 10 years of environmental studies,” said Jim MacKenzie, an energy specialist at the World Resources Institute, a Washington-based think tank.
Such concerns were heightened when President Bush announced in March that he had decided to renege on a campaign pledge to regulate carbon dioxide emissions from power plants as a pollutant.
According to Environmental Protection Agency Administrator Christie Whitman, the biggest single factor behind Bush’s decision was his concern that capping carbon dioxide emissions would “depress enthusiasm” for clean coal.
“We want clean coal technology,” Whitman said in an interview. “But it’s more expensive, and the fear was that talking about a mandatory cap on emissions would scare people away from those kinds of investments, and we knew we needed to have coal as part of the mix.”
Today, only two commercial gasification plants are in full operation: Polk and a plant in West Terre Haute, Ind. Both were built with hefty federal assistance.
Polk Station Put Into the Spotlight
Polk was built at the site of an abandoned phosphate mine, where the only signs of life usually visible from the sprawling complex are foxes, herons, alligators and other swamp flora and fauna. But the engineers and technicians who work here suddenly feel as if they have been plucked from obscurity and thrust into the spotlight of a high-stakes public policy debate.
“Coal is going to be king again someday,” said Tom Berry, an engineer who developed the plant for Texaco and was retained by Tampa Electric to manage it. “Gasification’s time is now. The market forces are moving in that direction, and it’s cool to be on the leading edge.”
Polk’s gasification equipment combines a mixture of coal and water with pure oxygen and heats it to 2,500 degrees under high pressure to produce a methane-like fuel called synthesis gas, or syngas.
Texaco, the leading producer of gasification equipment, has been gradually improving the technology. The company’s gasifiers can produce syngas from a variety of solid fuels, including petroleum coke, a byproduct of oil refining.
Suddenly, utility companies and independent power producers are clamoring to buy its gasifiers.
“We’ve had many, many inquiries,” said James S. Falsetti, a Texaco senior vice president. “We’ve got so many, it’s hard for us to keep up.”
Several factors have improved the economics of gasification. The cost of building gasifiers has dropped. Natural gas prices spiked last year; they are still high and subject to big fluctuations. Government pollution regulations make the technology more affordable in some parts of the country than traditional coal plants.
“We’re economic now,” declared James C. Houck, head of Texaco’s power and gasification operations.
The biggest black cloud on the horizon had been the possibility that the federal government would cap emissions of carbon dioxide. But it appears that prospect has been virtually ruled out for as long as Bush is president.
Berry, who talks with evangelical zeal about the possibility of making Polk cleaner still, has a plan for dealing with carbon dioxide. He is proposing a project to separate carbon dioxide from syngas before it is burned, and he hopes to sell it to Florida’s breweries for use in carbonation.
Still, energy experts say that reducing carbon dioxide emissions is perhaps the biggest long-term challenge facing advocates of coal-fired power generation.
Bush’s proposed budget for fiscal 2002 allocates $211 million for clean coal programs, almost three times this year’s budget.
The coal industry and many utilities are delighted to receive the attention. “As a company, we’ve been closely aligned with coal, which was a bad word during the Clinton administration,” said Laura Plumb, spokeswoman for TECO, Tampa Electric’s parent. “It’s not with the Bush administration.”
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Making Coal Cleaner
Coal’s best bet for the future rests with “clean-coal” technologies. In the Polk Power Plant, below, coal is converted into a gas that can be cleaned before it is turned into energy. Emissions are much better than those of old coal plants. But as the chart shows, such plants still pollute more than natural gas plants.
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Cleaner, but Clean Enough?
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Emission Polk syngas Polk natural gas Typical* Sulfur dioxide 0.17 0.0013 0.25 Nitrogen oxide 0.13 0.0064 0.84 Carbon dioxide 230 110 238
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*Coal-fired plant with modern pollution controls
Sources: Teco Energy, Associated Press
