Clean coal’s tech hurdle

The appetite for energy is growing, and American politicians are looking to domestic resources like coal to satisfy that hunger. The goal is make coal cleaner – by preventing carbon dioxide that’s emitting when coal is burned from going into the atmosphere. Researchers in Pennsylvania have been working for years to develop this technology, but it still has a long way to go. In the second report of our series on coal, WHYY’s science reporter Kerry Grens looks into what it will take to make clean coal a reality.

The appetite for energy is growing, and American politicians are looking to domestic resources like coal to satisfy that hunger. The goal is make coal cleaner – by preventing carbon dioxide that’s emitting when coal is burned from going into the atmosphere. Researchers in Pennsylvania have been working for years to develop this technology, but it still has a long way to go. In the second report of our series on coal, WHYY’s science reporter Kerry Grens looks into what it will take to make clean coal a reality.

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Transcript:

In Hugo Caram’s laboratory at Lehigh University, a labyrinth of coiled pipes carries a blast of gases, mimicking the emissions from burning coal. Within the pipes a porous material acts like a sponge and captures carbon dioxide passing through. Caram says the process works – but there’s a drawback.

Caram: Producing these fuels that are environmentally friendly takes additional energy. That’s one of the criticisms against these types of processes.

Caram says capturing carbon decreases energy efficiency by about a quarter. So he and others are seeking ways to make the process of carbon capture more efficient, and cheaper. While Caram is testing out one potential carbon dioxide sponge, scientists at the Department of Energy’s National Energy Technology Laboratory or NETL in Pittsburgh are screening dozens.

Sorescu: Right here we have about 400 processors.

Dan Sorescu, a researcher at NETL gestures to a dark room full of computer processors with blinking blue lights.

Sorescu’s group at the NETL uses computer modeling to predict how different chemical sponges will capture carbon.

Sorescu: We really are looking at different combinations of materials.

The idea is that capturing carbon dioxide before it gets into the atmosphere can slow the effects of greenhouses gases on the environment. Once the carbon is captured, it would be squeezed under high pressure into a liquid-like form and pumped underground. Tom Sarkus, the senior management and technical analyst at the NETL says there are vast stores of porous sandstone that could act as carbon reservoirs.

Sarkus: But you have to have over top of it a formation where the particles are a lot tighter and don’t allow the fluid to move through it so they’ll trap the CO2 underneath that formation.

Sarkus says there are enough formations underground to hold about 1,000 years’ worth of CO2 captured from coal burning.

Sarkus: I don’t mean to think we’re going to be injecting that much CO2 here. We only have about a 250 year supply of coal in this country at present levels. And once you really get down to it I think what we’re talking about is the next 50 to 100 years until we got to the point where nuclear and renewables are poised to take center stage.

Sarkus says that both carbon capture and storage underground have been demonstrated successfully. The next step will be to combine the two.

Sarkus: Sometimes it may appear easy or simple to couple or combine some of these technologies and it really isn’t. We run into what we call integration issues. We don’t have anywhere where that carbon sequestration is hooked up to an operating power plant. And that’s what we really need to do in terms of overcoming the technical challenge.

Sarkus is part of a Department of Energy program enticing companies to partner with the government and build the first coal electricity plant with carbon capture and storage. The project, called Futuregen, started several years ago, but expenses swelled and derailed its progress. Futuregen plans to continue, with the hopes of having a coal plant with carbon capture and storage ready by 2015. To get this technology up and running will a tremendous feat, on the scale of some of the biggest engineering projects, says Caram at Lehigh University.

Caram: The highway system. And I’m just taking a guess. The space program, these types of things. So do we want to go there? I think that we want to have good answers before we proceed, and it’s going to take time.

Caram says that for chemical engineers like himself, it is a call to arms to take on rising energy costs and global warming. For his part, he’s optimistic that clean coal will become a reality – in about ten or twenty years.

 

 

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