Engineering Professor Rich Axelbaum studies his "oxy-coal combustor," a device he hopes could someday trap CO2 in coal-fired power plants. (Photo by Matt Sepic)
Coal has a reputation as a sooty, dirty fuel. More recently, environmentalists and the coal industry alike have become just as worried about the carbon dioxide released when coal is burned. In the third part of our series on the future of coal, Matt Sepic has this look at the science behind so-called “clean coal”:
Transcript
Coal has a reputation as a sooty, dirty fuel. More recently, environmentalists and the coal industry alike have become just as worried about the carbon dioxide released when coal is burned. In the third part of our series on the future of coal, Matt Sepic has this look at the science behind so-called “clean coal”:
As far as most leaders of the coal industry are concerned, the debate about global warming is over. It exists, carbon dioxide contributes to it, and it’s a crisis. But as they’re quick to point out, nearly half the nation’s electricity comes from coal. It’s domestic. It’s relatively cheap. And there’s a lot of it.
Steve Leer is the CEO of Arch Coal. Leer says unless Americans want that power to get really expensive, coal will have to remain part of the equation. But he says something has to be done about all that carbon dioxide.
If we don’t solve that CO2 question, the backlash of high cost electricity becomes an issue for all of us.
Arch Coal is the nation’s second largest coal producer. It’s paying for research into carbon capture and storage. The idea is to divert CO2 from smokestacks, compress it, and then pump it underground.
Engineering professor Rich Axelbaum is studying this with money from Steve Leer’s company. In his lab at Washington University in St. Louis, Axelbaum and two students are tweaking a device they call an oxy-coal combustor.
RA: “It’s a relatively small scale, quite a small scale for industrial, but it’s a relatively large scale for a university.”
MS: “It looks like a few beer kegs stacked end to end and welded together.”
RA: “Right, right.”
Axelbaum can burn coal inside this furnace along with a variety of combustion gases. He’s trying to figure out exactly how much oxygen to inject to yield pure carbon dioxide.
“We can capture the CO2 from a combustion process, by instead of the burning the coal in air, you’re burning it in oxygen, so the stream coming out of the exhaust is CO2.
Axelbaum says there’s no sense in filling valuable underground storage space with CO2 mixed with other gases if a power plant is built that can grab nearly pure carbon dioxide and store it.
He says energy companies already pump CO2 underground to extract crude oil, so some of the technology already exists. But environmentalists say the next step – which is crucial for any so-called clean coal power plant to work– is far from proven.
“No one knows in the industry whether in fact they can sequester carbon permanently.”
David Orr teaches Environmental Science at Oberlin College in Ohio. He says storing CO2 underground is easier said than done. And nobody knows if rock formations in different parts of the country can hold the huge amounts of carbon dioxide America’s power plants produce without it eventually leaking out.
Orr says because the goal is to reduce global warming, politicians would be better off funding research into other energy alternatives.
The metric here is how much carbon do we eliminate per dollar spent on research and deployment of technology?
Orr says the 3.4 billion dollars set aside for clean coal research in the federal stimulus bill would be better spent studying wind and solar power, modernizing the nation’s electrical grid, and finding ways to improve energy efficiency.
But the United States still has more than a century’s worth of coal reserves. And with plenty of money going into both research and advertising, talk of carbon capture and storage is certain to continue, even if it remains just that.
For The Environment Report, I’m Matt Sepic.