by Craig Volland, Air Quality Committee Chair, Kansas Chapter
 |
Electric Power Producers in Kansas are planning to add some 3000 megawatts of new coal burning capacity by 2012. In addition KCP&L has recently received a permit (being appealed) to add 1050 MW in coal burning capacity at their Iatan site just north of the KC metro area near Weston, MO. To put this in perspective, Westar’s existing coal-fired generating capacity is 2638 MW and their total capacity, including nuclear, oil and natural gas is about 5800 MW.
The reason for this rush to burn coal is the soaring price of natural gas combined with the state’s proximity to relatively cheap Wyoming coal, though this coal is not at all cheap if the true costs of using it were accounted for. Power producers have little interest in aggressive campaigns to help customers reduce demand, and they are reluctant to take advantage of the vast wind resources in central and western Kansas.
So why should we care? Well there are tens of millions of tons of greenhouses gases that will increase global warming, increased fine particles that have been shown in the last 20 years to increase death rates particularly among the elderly and infirm and increased precursors to ozone smog which also increases mortality and aggravates certain chronic diseases like asthma. For now though, I’ll focus on mercury pollution. Mercury that was absorbed by ancient plants millions of years ago and pressed into coal is about to make a redux into our atmosphere. The rush to burn huge quantities of Wyoming coal becomes a special problem for down winders in the eastern third of the state.
People can easily get confused about mercury. Why is it such a concern? After all, I played with the silvery elemental mercury when I was a kid, and I’m still here. Well, it all depends on which type of mercury you are exposed to and how it enters your body.
 |
Elemental mercury is the only metal that is a liquid at room temperature. It doesn’t exist in nature in the form we played with. Primarily because it is useful in processing gold, humans have, for many centuries, dug mercury out of the earth, where it was perfectly happy married to sulfur in cinnabar ore, and then drove it off with heat. This lonely substance takes every opportunity to escape and find its way back home by attaching to carbon and/or sulfur in plants or in the soil, to eventually become buried in sediment where it can go out of the ecosystem undisturbed.
Our problem is that it wreaks havoc all along the way, by flirting with other elements or compounds that are highly toxic to humans. The worst thing we can do is to send this chemical in vapor form out of a tall stack so it can spread evenly over the landscape and wash into streams and lakes. Mercury falls out primarily in rain.
Elemental mercury is almost insoluble. If you swallow it, almost all passes on through. But if you breath it in vapor form it is absorbed into your bloodstream and can get into the brain where it does its damage. One normally is not exposed to enough mercury in the air to get hurt. It’s a particular mercury compound that causes the problem.
Mercury is most toxic to the human fetus. In 2004 the USEPA announced that one in six women of child bearing age have levels of mercury in their blood that could be toxic to a fetus. How did this happen? Mercury exits a smoke stack and falls into or is washed into both fresh and marine water bodies where it can be transformed by bacteria into methyl mercury. Methyl mercury is taken up by fish and concentrates in those fish species at the top of the food chain. When ingested the methyl mercury, unlike elemental mercury, is taken up by the digestive system and even more easily gets into the brain. Methyl mercury is one of the most potent neurotoxins known. It is so toxic that fish are considered contaminated if they contain less than one half of one part per million of the fish’s weight.
Few Americans eat a significant amount of freshwater fish. However, they do eat a lot of seafood and that’s where the vast majority of our mercury body burden comes from. We have so polluted the world’s oceans that mercury levels are now beyond the threshold of harm such that any more consumption by certain people, like pregnant women can be harmful. Also relatively small subsets of our population like anglers and poor (often rural) people who rely on freshwater fish in their diet are especially at risk.
Coal fired power plants are the largest source of mercury in this country. The USEPA last year issued new regulations, called the Mercury Rule. EPA set an emission limit that was designed to let power producers off the hook until 2010. Then they can participate in a “cap and trade” program until 2018 at which time the total of US mercury emissions is supposed to be down by about 65 percent from current levels. Fifteen states are suing the EPA because they believe the cleanup will take too long, and the cap and trade program could lead to concentrations of emissions or “hot spots” in parts of the country. All of Missouri’s lakes and streams are already under a public health advisory for mercury in fish. Levels in Kansas have been shown to be rising in recent tests.
EPA tried to justify their extraordinarily complicated and industry-friendly Mercury Rule by claiming that only eight percent of the wet deposition of mercury nationwide comes from US power plants. The rest floats in from foreign sources. Even if that were true, it doesn’t matter because the vast majority of mercury now lodged in people’s brains comes from seafood, much of it imported from all over the world. So our mercury emissions can come back to us in a can of tuna from Thailand.
But a new study has blown EPA’s claim out of the water. Researcher found that 70 percent of mercury found in rainwater in Ohio came from nearby coal burning industrial plants. So no matter where our lonely, promiscuous little mercury vapor comes from, or ends up, it’s trouble.
That what we get for digging up billions of tons of coal across the world in the past 150 years, a mere blip in geologic time. Add to that all the mined mercury in batteries, pigments and electrical switches we burned in garbage incinerators. Had humans been exposed to methyl mercury gradually over tens of thousands of years we might have developed defense mechanisms in our bodies. For example dolphins and whales, at the top of the marine food chain, have been exposed for a very long time and consequently can tolerate much higher body burdens of mercury. We have become victims, again, of our voracious appetite for energy.
Anyway, back to power plants. It turns out that utilities that burn eastern US coal can get about a 90 percent reduction of mercury by installing the same equipment they soon will have to install anyway to remove acid gases. That’s because eastern bituminous coal contains a significant amount of chlorine. Mercury quickly combines with chlorine in flue gases to form mercuric chloride which is very soluble and easily removed by scrubbers. Wyoming coal, on the other hand, contains very little chlorine, and less than 25 percent of the mercury can be removed by the dry-type scrubbers used out west. So what may happen is that utilities burning Wyoming coal will buy the excess credits (the right to pollute) from eastern utilities and eastern Kansas and Missouri could become a mercury “hot spot.”
The largest chunk of the new capacity in Kansas will be three new boilers totaling 1950 MW planned by Sunflower Electric at their existing Holcomb, KS site near Garden City. Most of this power will be sold to customers in Colorado. The others plants are planned by Westar at 650–800 MW and by the Bureau of Public Utilities in Kansas City, Kansas at 250–300 MW.
Mercury removal tests at Sunflower’s 360 MW Holcomb 1 coal fired power plant, co-sponsored by Westar and BPU, demonstrated that injecting carbon into the flue gas from burning Wyoming coal would remove over 90 percent of the mercury. In another, short term experiment, Sunflower mixed in some bituminous (presumably high chlorine) coal from Colorado and got up to 80 percent removal. Nonetheless Sunflower has not yet committed in their permit application to a tight mercury limit.
If they don’t, and instead choose to buy mercury emission credits, a large quantity of mercury will travel on the prevailing winds to eastern Kansas, where it rains much more frequently, and to points east and north. Westar and BPU haven’t said what they plan to do about mercury. Fortunately, after much citizen pressure, KCP&L agreed to avoid increasing mercury emissions at Iatan, though it will remain a significant source.
If you want to keep eastern Kansas from becoming mercury hot spot you need to contact your legislators and express your concern about this new wave of coal-fired power plant construction in Kansas. Mercury is only one of many reasons why we shouldn’t be burning more coal. .