Could cuts in emissions come faster?

Deep in the Allegheny Mountains of West Virginia sits a giant coal-fired power plant aptly named Mount Storm - a 1,600-megawatt goliath that just a few years ago ranked second in the nation in toxic mercury emissions.

Today, however, the plant is turning over a new leaf. Since new pollution controls were bolted onto the plant, sulfur dioxide (SOX) and nitrogen oxides (NOX) are now scrubbed out of its smokestack emissions. The even better news is that a lot of mercury is being captured, too, scrubbed out at the same time at no extra cost, a company official says.

The plant's success casts an odd light on the nation's new Clean Air Mercury Rule, announced Tuesday. If existing technology can remove the lion's share of mercury emitted at a majority of today's power plants, why does the new law wait until 2018 to impose similarly stringent limits?

That's what environmentalists are asking. "The bottom line is that the technology is available today to eliminate the vast majority of the mercury mess," says Frank O'Donnell, president of Clean Air Watch, a Washington, D.C. watchdog. "Instead, EPA has given the power industry a decade-long pass."

Industry experts say the picture is not so simple.

"There's been a running argument about the status of technology for a couple of years now," says Larry Monroe, program manager for emissions-control research, at Southern Company in Atlanta, the nation's second largest public utility. "We have to be sure this equipment works 100 percent of the time. It has to be robust. A lot of people don't understand this stuff isn't ready for prime time."

For example: New technologies like activated carbon injection, which would absorb mercury from the emissions, are still in early stages of testing. And while NOX and SOX removal technologies are well-proven, Mr. Monroe says, their ability to remove mercury depends on coal type and power-plant configuration. For one thing, they don't remove mercury well from coal mined in the western half of the United States - although the mercury problem is most acute in the eastern US, where mostly bituminous coal is burned.

Nevertheless, where the NOX-SOX combination works, it often works well. Southern is in the process of adding two giant SOX scrubbers costing hundreds of millions of dollars to power plants that already have NOX controls. When he throws the switch on the new controls in 2007 and 2008, Monroe expects that together these systems will capture about 80 percent of the mercury, too.

The nation's coal-fired power plants currently emit about 48 tons of mercury a year. The toxin, along with mercury blown in from other countries, settles in rivers and lakes and enters the food chain, concentrating in fish. There are mercury fish advisories in 44 states, and the toxin has been found in women of child-bearing age.

The new mercury rule represents the first time the US has regulated mercury emissions from power plants.

"In so doing, we become the first nation in the world to address this remaining source of mercury pollution," Steve Johnson, acting administrator of the US Environmental Protection Agency, said in a statement announcing the new rule.

Under it, power plants are expected to cut mercury emissions from 48 tons currently to 38 tons by 2010 - and cut to 15 tons by 2018, a 70 percent reduction, using mercury-specific technologies.

Much of that first-phase reduction is expected to occur through "cobenefits" - cuts that occur by doing nothing more than meeting another new set of clean air requirements announced last week for reducing NOX and SOX. Those reductions are called the Clean Air Interstate Rule (CAIR).

Relatively few power plants today have both NOX and SOX removal gear like Mount Storm's. But under the new rule there should be many more Mount Storm-like conversions, experts say.

A key feature of both sets of new EPA rules is the use of market-based cap-and-trade systems. Under these, pollution allowances for mercury, SOX, and NOX may be purchased or traded by utilities. Such NOX and SOX removal systems may be efficient enough that they one day generate mercury credits sold on the open market - or compensate for other more polluting plants.

At Mount Storm, for instance, researchers for two pollution control companies ran three weeks of full-scale tests on how well NOX and SOX equipment removed mercury. In a research paper delivered this month, they revealed the two systems working together cut 98 percent of mercury emissions - a clear success.

"It was a nice result," says Tom Hastings of Cormetech, one of the pollution-control companies. "This plant is a good example. But I've also seen numbers in the 80- to 90-percent-plus range for a number of others."

And that's the sort of thing that bugs Mr. O'Donnell, the environmentalist, who says that companies have the capability to do more with the technology presently available - if the EPA would just make them do it.

Right now, for instance, the Mount Storm plant runs its SOX scrubber year round - but runs its NOX removal gear only five months a year, during the summer when it's a problem. But without the NOX system running, SOX alone removes about 70 percent of the mercury.

Whenever it decides that the cost of emitting the mercury under the new mercury rule exceeds the cost of running its NOX equipment year round, the company can throw a switch and remove more than 95 percent of its mercury.

When will that day come? When purchasing mercury-pollution allowances becomes more expensive than running NOX equipment year round, experts suggest. Or, at the latest, the new CAIR rule will require NOX equipment to begin operating year round at Mount Storm beginning in 2008, a company official says. Until then, much less mercury will be removed than is possible, if the tests conducted last summer are any indication.

Not to worry, say company officials.

"Mount Storm has become one of the cleaner plants in the country right now," says Dan Genest, a spokesman for Dominion Resources, headquartered in Richmond, Va., which operates Mount Storm and other power plants in several states from Illinois to Massachusetts. "Under the CAIR rule, we may not have to do as much [mercury reduction] at one of our other plants in Virginia, thanks to the cuts in mercury at Mount Storm. By doing that we would still end up complying with the mercury rules anyway."