WASHINGTON, D.C.—A recent report by a non-partisan environmental law-enforcement group ranked the seriousness of American power plant emissions and disclosed a list of the fifty filthiest.
"Nationwide, power plants account for roughly two-thirds of all sulfur dioxide (SO2), 22% of nitrogen oxides (Knox), 40% of carbon dioxide (CO2) and roughly one-third of all mercury emissions," said the report released late last month by the Environmental Integrity Project (EIP).
The nation's nearly 400 major power plants can be assessed on each of the four pollutants by using a ranking system for the worst polluters. The 2006 report is the first time the EIP has used a composite score by combining the emissions "rate" rankings of the four pollutants.
According on the combined rankings across four pollutant categories (sulfur dioxide, Knox, carbon dioxide and mercury), the worst three plants are in North Dakota. A list of the fifty dirtiest plants can be found at the report Web site, dirtykilowatts.org.
The EIP ranks plant polluters by using data made available to the public from the Environmental Protection Agency (EPA) and the Department of Energy (DOE) in 2005.
Power plants emit millions of tons of sulfur dioxide and Knox, which trigger asthma attacks and contribute to lung and heart disease. They also emit billions of tons of carbon dioxide, which has been linked with global warming. Another is mercury, a neurotoxin especially harmful to children and developing fetuses.
The EIP says that a "disproportionate share of emissions comes from a handful of old plants that have been slow to install pollution controls, or which operate inefficiently."
A mere 4% of the nearly 1,200 fossil fuel burning power plants in the country are responsible for 45% of all sulfur dioxide emissions.
Environmental laws intended to provide protection from dangerous pollutants have loopholes that have allowed some plants to evade stricter measures of operation. For instance, when the original Clean Air act was passed in 1970, several of the older power plants were "grandfathered" into the act, evading stricter pollution controls.
Some of these electric power companies choose to clean up their plants based on business decisions, while others elect to "buy their way out of emissions caps," said Ian Levin, counsel for EIP and primary author of the report, referring to the right under the EPA's rules in most eastern states for plants to bank, buy, and sell their pollution emissions as long as certain ceiling levels are met.
Options for Change
Scrubbers, which rely on a chemical reaction with a sorbent to remove pollutants, can effectively reduce plant pollution emission rates. "The top 50 plants averaged 22 pounds of sulfur dioxide per megawatt-hour, compared to only one pound per hour for plants with state of the art scrubbers," highlighted the EIP report.
Large coal-fired power plants equipped with scrubbers have shown that cleaner power is attainable. The report mentions a plant in Pennsylvania and two in West Virginia that used wet limestone scrubbers and achieved sulfur dioxide emission rates of approximately one pound per megawatt hour—well below the average of 22 pounds of the dirtiest 50.
The report noted that many companies that own plants emitting large quantities of sulfur dioxide have not made commitments to installing scrubbers by 2010, the deadline for meeting air quality standards which limit fine particle pollution.
Measuring Rankings
The ranking of power plants really depends on the type of measure. EIP uses three types. One way is to measure the amount of pollution per unit (megawatt-hour) of electricity generated—an emission "rate." A second way is to ignore the amount of electricity produced and focus instead on the total tons of pollutant emitted—a gross impact on public health and the environment. (Mercury is so harmful that it is usually measured in pounds, not tons.)
Additionally, you can find the dirtiest power plants on each of the four main pollutants by two measures: emissions rate and total tons at the above website. The rankings in the EIP report include the 376 largest power plants in EPA's emission tracking system database for 2005. EIP states that these plants represent a third of all power plants tracked in EPA's inventory and account for about half of the total U.S. electric generation.
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