‘Clean coal’ power: Real or imagined?

Navajo generating station, photo by Cisco/Flickr

ALBUQUERQUE — “Clean coal” — It’s a phrase inserted in what’s become a political litany of strategies to reverse global warming while still meeting our future energy needs.

Both Barack Obama and John McCain feature it in their energy plans, with Obama even including a promise to invest in clean coal technology in his convention speech.

Closer to home, Gov. Bill Richardson has also endorsed “clean coal.” In an interview with online environmental magazine Grist last year, he said it had to be part of the mix of our future energy supply, and that he “dramatically” favored it over nuclear energy:

I believe that carbon-clean coal will play a role in our energy future. There have gotta be some very strict clean-coal standards. I’m not an advocate for continuing to use old oil, coal, and nuclear. … My dramatic preference [between coal and nuclear energy] would be for clean coal. …And I opposed giving a tax incentive in New Mexico to just a regular coal plant that’s proposed here, Desert Rock. I can’t be the champion of global climate change and have a new coal plant that isn’t clean.

While there are a few hold-outs, most people acknowledge that we’re experiencing a human-induced climate change that poses a global threat. So the rush is on to figure out ways to lower the culprits — greenhouse gas emissions. The main one being carbon dioxide, or CO2.

CO2 is a naturally occurring gas that gets emitted into the atmosphere and then re-absorbed by the earth’s oceans or forests. The problem we’re faced with now results from increasing CO2 due to the burning of fossil fuels. The increase is large enough that not all of it can be re-absorbed naturally, so some of it gets trapped in the atmosphere, leading to increasing temperatures over time.

Global warming is already being credited with major environmental changes that could have profound and destructive impacts on human habitats.

In other words, we may soon be an endangered species ourselves.

And how to deal with it is a bit of pickle. Our problem is that we’re highly dependent on CO2 belching fossil fuels. And one of those — coal — is cheap, plentiful, and easy to transport, even if getting at it is destructive, sometimes requiring the removal of entire mountaintops.

Coal, in fact, is the fastest growing source of energy in the developing world, particularly in China, and is directly responsible for increasing global CO2 emissions. And most analysts predict its use will only continue to grow.

Hence the efforts to make it “clean” — a moniker that many consider misleading because coal-fired power plants are a major source of localized pollution, aside from the global problems with CO2.

Additional pollutants include sulfur dioxide, nitrogen oxides, as well as particulate matter. These three combined can create a toxic localized smog that increases cancer and respiratory illnesses.

Coal-fired power plants are also a significant source of mercury, a known health hazard which gets into rivers and streams, polluting the fish. If you’ve ever gone fishing and been told to not eat what you catch, it may be because of mercury poisoning.

“There is no such thing as clean coal. It’s dirty and full of carbon, much more than oil or natural gas. It’s dirty to mine and causes a lot of pollution in general,” Ned Farquhar, western energy and climate advocate for the Natural Resources Defense Council, told the Independent.

Michael Casaus, the Sierra Club’s New Mexico field director, echoed those thoughts. “Clean coal is an oxymoron when you consider the effects of mining itself plus all of the other pollutants, such as mercury,” he said.

In the United States, 90-95 percent of the coal we mine is used to produce electricity, accounting for over 50 percent of U.S. electricity, and generating a whopping 90 percent of New Mexico’s electricity. Electricity generation produces about 41 percent of total U.S. emissions of CO2. Combined with the much smaller other sources of coal-based greenhouse gas emissions, this means that coal produces about 20-25 percent of U.S. based CO2 emissions.

So, in effect, we depend on coal to turn on our lights at the same time it’s making us sick.

Can coal be made cleaner, if not completely clean?

Jim Norton, Environmental Protection Division Director at the New Mexico Environment Department, told the Independent that in Gov. Richardson’s usage, the term “clean coal” is mainly about using carbon capture and sequestration (CCS) technology to keep CO2 out of the atmosphere.

CCS technology involves separating CO2 from other gases during the coal burning process and injecting it permanently into the earth, rather than letting it enter the atmosphere. The technology to isolate CO2 is largely understood, but the ability to inject it safely and permanently deep into the ground, or the ocean, has yet to be adequately developed. Most analysts project that CCS won’t be a commercially viable technology until at least 2020.

Many view “clean coal” more expansively, though. The cleanliness of coal is on a continuum of sorts, with promising technologies on the horizon.

For instance, technological gains have allowed pulverized coal plants to be retrofitted, or built, to be more efficient. Greater efficiency reduces the amount of coal needed to produce energy, thereby lessening the amount of coal pollutants emitted into the air. State of the art “super critical” pulverization plants increase efficiency to about 41 to 45 percent, from the 35 to 40 percent efficiency of older “sub critical” plants.

Then there is coal gasification, or “IGCC,” which mixes coal with oxygen and water to make “syngas.” Syngas is then burned at much higher efficiencies than traditional pulverization plants, possibly as high as 60 percent. This method also allows CO2 to be separated from other chemicals, making it easier to sequester.

IGCC is a new technology employed currently by only two plants in the United States. The technology is capital intensive and still untested to the degree necessary to make it commercially viable on a broad scale.

Norton told the Independent that new coal plants should push the envelope with IGCC technology, though, so that they’re prepared to adapt to CCS technology when it becomes available. “Coal gasification makes sequestration easier because the CO2 can be pulled off and piped directly into the ground,” Norton said.

One of the biggest challenges in developing clean coal technologies is the balancing of resources, given competing claims for tax incentives for research and development, and commercial projects. Given the climate change imperative, many believe public resources should primarily be directed toward the development of “green” renewable energy sources.

Nonetheless, most will acknowledge a future with coal in it — but with a strict environmental bar set for its future use.

“The only acceptable route to future use of coal is 85 percent removal of carbon throughout the mining and combustion process,” Farquhar said, “with permanent geologically secure sequestration to dispose of the carbon.”

“The entire production cycle has to be looked at, including the energy cost of the mining process,” he said. “If coal is going to be in the mix, we should say fine, but there’s a needle through which this camel must pass.”

Editor’s note: New Mexico is currently in a big fight over the use of coal, due to a new, proposed power plant — Desert Rock — proposed for the four corners region. One of the major objections to the Desert Rock coal-fired power plant is that, while much cleaner than older models, it’s still a less-efficient pulverized coal plant. Part two of this report will examine the fight over Desert Rock, which encapsulates the debate about the cleanliness factor of coal.