In anticipation of the Environmental Protection Agency setting new nationwide standards limiting mercury and other toxic emissions by late November of this year, Environment America released a report ranking power plants according to the amount of mercury they’re putting into the air and soil.
The group, using EPA data, ranked a Montana power company the 11th-biggest coal-fired polluter of mercury in the nation and the worst among those in Western states. According to its report, “Dirty Energy’s Assault on our Health: Mercury,” Colstrip Steam Electric Station in southeast Montana emitted 1,490 pounds of mercury in 2009. This accounted for most of the 1,726 pounds of mercury released by all of Montana’s power plants that year.
Mercury, a neurotoxin, is linked to developmental and brain defects, as well as kidney damage, especially in developing fetuses. Exposure to high doses can result in death. It occurs naturally in the earth’s crust and is present in air, water and soil. It is also found in various rocks, including coal.
Environment America, a federation of 29 state-based organizations, is calling on the EPA to issue a stringent standard that will cut mercury pollution by more than 90 percent. But this is not an easy task.
“The EPA is facing a lot of difficulty in Congress right now, in terms of their ability to regulate pollutants through the Clean Air Act,” says Mollie Allers, state associate for Environment Montana.
“Some in Congress are hoping to delay their action in regulating these pollutants. It’s faced a lot of opposition from strong industry powers in Congress that are seeking a less stringent rulemaking,” she says.
According to the EPA, coal-burning power plants contribute more than “50 percent of all domestic human-caused mercury emissions” in the U.S. This makes them the largest source of airborne mercury pollution in the country.
Gordon Criswell, director of environmental and engineering compliance at PPL Montana, the company that co-owns and operates the Colstrip plant, said that the plant has actually cut its mercury emissions by 85 to 90 percent in 2010 after installing a new mercury control system.
Criswell says the 2009 ranking is due to the size of the plant, where four coal-fired units burn about 10 million tons of coal a year. This is equivalent to one rail car’s worth of coal every five minutes, according to PPL Montana.
Four plants in Texas ranked in the top 10 of the most severe polluters. The Martin Lake Steam Electric Station and Lignite Mine, in Tatum, finished worst in the nation, emitting 2,660 pounds of mercury, according to the report, which evaluated more than 450 plants.
The report highlights that the top 25 largest mercury polluters are based in 12 states, with four states—Texas, Pennsylvania, Ohio and West Virginia— responsible for 68 percent of the mercury emitted by the top 25.
Tighter Montana Regulations in 2010
Montana is one of 19 states that have introduced a standard for mercury emissions. As of Jan. 1, 2010, this restricts plants to releasing 0.9 pounds of mercury per trillion Btu, calculated on a rolling 12-month average. (Btu is an energy measurement. It is roughly the amount of energy needed to heat one pound of water by one degree Fahrenheit.)
Colstrip complied with this standard in 2010, says Debbie Skibicki, lead environmental engineer at the Montana Department of Environmental Quality’s air permitting section. She says the plant’s 2010 average was 0.8 pounds of mercury per trillion Btu.
Allers points out that there remains some leeway. Power plants have until July 1 of this year to apply for an alternative emission limit if they are unable to meet the state standard. However, their application must show how compliance with the state rule is “projected to be achieved as soon as reasonably practicable but no later than 2018,” according to the legislation.
Mercury reduction systems, such as that installed at Colstrip, use an oxidizer to convert the mercury byproduct from an elemental to an oxidized state, Criswell explains. In this form, it can attach to activated carbon particles, which are injected downstream of the furnace, and then removed.
While mercury emissions are restricted in Montana, mercury pollution does not respect state boundaries, says Allers. “That’s why it’s important that the EPA regulate coal-fired power plants throughout the United States, because many states have not developed their own mechanisms for reduction,” she says.
“It’s possible that mercury pollution from bordering states will come and affect Montana’s waterways and our health, even though we have implemented our own reductions,” she says.
How Mercury Spreads
When coal is burned, mercury is released into the atmosphere. In its elemental, form mercury can remain airborne for as long as a year and has the potential to travel. Scientists have found mercury pollution in California that can be traced to emissions from Asia.
Power plants also release mercury in other forms, known as oxidized and particulate-bound, that stay in the atmosphere for shorter periods, restricting the range of their dispersal.
Mercury is brought down to earth by rain, snow and dust. Eventually, it winds up in oceans, rivers and soil. Bacteria living in soil and water convert mercury into methylmercury, which can be hazardous to human health.
In water, methylmercury works its way up the food chain in an exponential fashion. Small plants and animals consume the substance; larger fish eat these creatures, resulting in a build up of mercury in their tissues. Larger fish that eat these mid-level predators take in a higher concentration.
According to the EPA, almost all fish and shellfish contain traces of mercury, but this does not pose a health risk for most people. However, a 2000 EPA report highlights that “more U.S. waters are closed to fishing because of mercury contamination than any other toxic contamination problem.”
The EPA emphasizes that risk is based on how much fish is eaten and the levels of contamination in the fish. Women and children are advised not to eat larger species such as shark, swordfish, king mackerel and tilefish.
Mercury Down at Colstrip, but Carbon Dioxide Still at Large
In a 2009 report, “America’s Biggest Polluters,” Environment America identified the Colstrip plant as the ninth “dirtiest” in the country, responsible for pumping 19.3 million tons of carbon dioxide, a greenhouse gas, into the atmosphere in 2007.
The EPA’s figures for 2010 indicate that Colstrip released 18.7 million tons of carbon dioxide in 2010.
“Carbon dioxide is directly related to the amount of coal you burn because carbon is a main component of coal,” says Criswell. “Colstrip, being one of the largest plants in the country, is going to be rated high, because of the amount of coal we’re burning.”
Carbon capture technology for coal-fired plants is still at its early stages, Criswell says. Colstrip is working with the Energy and Environmental Research Center at the University of North Dakota to better understand what types of controls could be used, he says.
The EPA will propose its carbon dioxide emissions standards for power plants in July of this year, with final standards due to be issued in May 2012. Final standards for mercury emissions are due by Nov. 16.