Ken Silverstein EnergyBiz Insider Editor-in-Chief

The vast majority of coal used today is pulverized, meaning it has been crushed to a fine dust before it is shifted to a furnace and burned. Older coal-fired plants are the least efficient with about 35 percent of the energy input converted to electricity. But, as more power generators opt for supercritical units with higher water-side operating pressures the efficiencies associated with pulverized coal units can increase to 40 percent, or even higher. Considering the tonnage of coal burned each year, those improvements could have a dramatic effect on the environment.

"We've made a voluntary commitment to reduce our carbon dioxide (CO2) emissions -- ultimately -- by 50 percent," says Doug Topping, senior vice president of generation for EPCOR, with offices in Alberta, British Columbia and Ontario, Canada. "We will annually take our actions to the regulator for approval."

At a conference sponsored by Marcus Evans Ltd. in Amelia Island, Fla., Topping told an audience that his company's Genesee 3 coal plant rated at 450 megawatts uses advanced coal combustion technology. It took three years to get regulatory approval and has been on line for about 10 months. During that time, it has been operating at about 92 percent capacity with almost no forced outages.

The utility exec said if the company were starting a new coal plant today it would use integrated gasification combined cycle technologies, or coal gasification. Efficiencies could then reach as high as 60 percent, although the cost to build would be about $1,200-$1,600 a kilowatt compared to $900 with conventional coal plants. "This is where you can expect the industry to be going forward and we expect to be there."

When coal is burned, it produces sulfur dioxide and nitrogen oxide -- the stuff that produces acid rain and smog -- as well as particulate matter and mercury. Under the Clean Air Act, those pollutants must be removed from exhaust gases that come out of the smoke stack on the backend. The combustion of coal also produces substantial quantities of CO2, which is not currently regulated but the pressure to do so is increasing.

By contrast, coal gasification removes the sulfur dioxide, mercury and carbon dioxide from the "syngas" before it is combusted, say experts. And because the "syngas" is cleaner than raw coal, lower quantities of nitrogen oxide and particulate matter are produced during the combustion or burning process, they say. The CO2 is more concentrated, which makes it easier to capture. Four such plants are operating now: two in the United States and two in Europe.

Carbon Sequestration

American Electric Power wants to begin constructing a coal gasification plant in Ohio this year, with the facility operational by decade's end. Cinergy Corp. is trying to do the same in Indiana. While Ohio regulators and the utilities disagree about how the cost of these plants -- $1.3 billion in AEP's case -- is to be paid, utility commissioners note that the average age of coal-fired generators in the state is 44 years-old, necessitating the newest innovations.

"The principal environmental benefits associated with coal gasification are significantly lower air pollution emissions in the short term and more cost-efficient CO2 capture and sequestration in the long term," says Brian Ferguson, CEO of Eastman Chemical Co., in testimony before Congress. "As additional commercial-sized coal gasification plants are built, the competitiveness of this environmentally superior technology should become more evident."

The U.S. Energy Department is working on FutureGen that it says will be emissions free, costing $1 billion. A site for the plant is expected to be chosen sometime next year. It is based on coal gasification technology and would capture air pollutants before turning them into useful byproducts such as fertilizer. The project also would capture about 90 percent of all CO2 emissions that are thought to cause global warming. The agency says that as much as 250 billion tons of CO2 could be captured and buried by 2050 if the country moves toward advanced coal technologies.

Many green groups say that there is no such thing as "clean coal." Others say that as long as coal remains a vital part of the energy mix that government should require utilities to use the most modern technologies available, putting those heavily polluting coal plants out of business. They also want more federal support to go toward research and development of carbon sequestration, although they acknowledge this could divert resources from sustainable energy forms such as wind and solar power.

"If new coal plants are built, they should at least use this modern technology that may be able to control global warming pollution," says the Sierra Club.

Retrofits v. Replacement

While the older coal fired plants pale when compared to modern power facilities, the aging plants won't likely be retired anytime soon. Utilities with those plants say that they need the capacity. They also reason that it is cheaper to retrofit them with pollution control equipment than to replace them altogether. AEP, for example, is putting scrubbers on all its plants at a cost of $1 billion.

Other types of equipment add efficiencies so that plants produce more megawatts with the same energy input. Obviously, the facilities not operating at optimal levels are the ones with the most to gain. Competitive and regulatory pressures mean that plant operators can't pass through excess and waste to ratepayers.

Of the coal plants on the drawing board, only a small number are to be designed using coal gasification technologies. The rest will use pulverized coal. Altogether, about 120 new coal plants with a total capacity of 50 gigawatts are under consideration.

"Even a 1 percent improvement in efficiency means a lot," says Jeff Koksal, district sales manager for Diamond Power International in Lancaster, Ohio. "If we multiply that by the number of megawatts out there, we would see a meaningful increase in energy output and a decrease in pollution levels."

Coal-fired generation is going through some evolutionary changes. Older coal-fired plants are giving way to newer pulverized processes that use higher temperatures to create more efficient processes. Even better is the move toward coal gasification technologies that can nearly eliminate harmful pollutants and potentially bury CO2 emissions.

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