Science Interviews

Interview

Sun, 21st Jan 2007

Carbon Capture and Storage

Professor Jon Gibbins from Imperial College

Part of the show Alternative Energy, Climate Change and Carbon Capture

Chris - We've heard from Eric Wolff that carbon dioxide's the culprit, well what are we going to do with it? Jon Gibbins is here with us from Imperial College in London. So you reckon the answer is that we don't dump the carbon dioxide in the atmosphere in the first place, we've got to put it somewhere.

Jon - The big problem is the fossil carbon that was locked up hundreds of millions of years ago that's getting into the atmosphere at a much higher rate than we can take. What we're trying to achieve to mitigate the risk of climate change is quite interesting. We talk a lot about the rate of emissions, but not so much about cumulative emissions. We're looking at being able to put about 500 billion tonnes of carbon into the atmosphere and still have a reasonable risk of avoiding dangerous climate change. But there's probably ten times as much carbon as that in fossil fuels.

Chris - So in other words there's a time bomb sitting beneath the surface of the earth just waiting to go off if we unleash it. How do we get around the problem, because we need energy don't we?

Jon - we do, but the amount of energy we need is quite variable. I think you can get quite fixated on saying we'll give people as much energy as they want. If we just think about CO2, we could say if we didn't have the fossil fuels there, we wouldn't have a problem. We wouldn't have quite so much energy but we'd adjust. But the big thing to say is that if you're going to use fossil fuels, you have to use them in an environmentally responsible way. And ultimately that means capturing the CO2. One of the things we do worry about, and I worry about quite a lot, is that if you leave them there and don't use them. For example if you use wind energy which we've just heard about, effectively you're saying you've left some fossil fuel in the ground by using that wind power. But for that to do any good, we have to not use it for the next 3000 years.

Chris - So what you're advocating is that if we have a coal power station opening in China, and every single week they're opening a new one. What you're saying is that in China and everywhere, we need to have some way of making sure that the CO2 is not going into the atmosphere. How do we do that?

Jon - There's essentially three ways. One way is to capture the CO2 that's coming out of the chimney, scrub it out with a solvent that absorbs it, then release it as a concentrated gas, compress it till it's liquid and then put it underground. Another way is to burn the coal with oxygen so you just get a reaction that makes carbon dioxide directly and you clean it up a bit, and put that underground. A third way is to gassify coal, turn it into a fuel gas in which the carbon exists as carbon monoxide, and then instead of reacting the CO with oxygen to make CO2, react it with water vapour to make hydrogen. Then separate out the carbon dioxide and put that underground.

Chris - How much energy does it take to clean up the CO2 coming off a coal fired power station? And therefore how much more coal will you have to burn to make up the amount of energy you're sinking into these clean up mechanisms?

Jon - We have probably 10 times as much coal as we can safely put in the atmosphere. You have to recalibrate your thinking.

Chris - But are we flogging a dead horse? Should we say just don't burn these fuels and sink the money into not producing it in the first place?

Jon - If you think you can get the Chinese to follow along with that, go and tell them. I think you've got a lot more chance of asking people to modify the way they're operating, by a relatively small amount, burning perhaps 20 percent more coal. It's basically carrying on with life as usual but not putting CO2 in the atmosphere. As an example: if we were talking about dealing with the carbon dioxide from oil, costing say $50 a tonne to deal with it, that would add the equivalent of $20 to a barrel of oil. You wouldn't notice it.

Chris - What's the state of the technology that's dealing with this? Are we in a position to make this a reality?

Jon - We are certainly in a position to make it a reality. We're not in a position to roll it out on all new power plants overnight. We're talking about developing some big technology. Power plants have to be reliable, they need to run for a long time. We need to learn how to do it, and actually what's very important, is how to get the first plants built. The EU just announced it wants to have up to 12 plants with Carbon capture and storage running in Europe by 2015. But what they don't say is when the first one of those is going to be built. We're just debating in the UK at the moment how to fund one or two plants with carbon capture and storage that will be flagship projects for the world.

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