AUDIE CORNISH, HOST:
You know when you have a goal and you're nowhere near meeting that goal? Well, that's where the world is right now with reducing carbon emissions. Scientists have said emissions from fossil fuels must fall to zero by mid-century to avoid the worst effects of climate change. Now, if we're going to get to zero, it will take some dramatic measures, including much better ways to capture carbon dioxide. NPR's Jeff Brady is here to help us understand all this.
Jeff, let's start with the basics. What do we mean when we say carbon capture?
JEFF BRADY, BYLINE: Well, it could be two things - either capturing it, say, from a smokestack before it's released into the air or pulling it out of the air after it's already there. And you can capture CO2 before it's released from a smokestack using a chemical process. There are examples of this. There's one in Texas at a coal power plant. About 10% of that plant's emissions are captured. There's another that I've seen up in Alberta, Canada, that's reducing emissions from a fossil fuel plant. But both of these projects - they're expensive. They're heavily subsidized, so we haven't seen many plans for more plants like those. One was recently announced for an existing coal plant in New Mexico, but that's at the very beginning development stages.
CORNISH: And the carbon dioxide that's already in the atmosphere - talk about how you capture that.
BRADY: This a lot trickier because the CO2 isn't concentrated like it is at a smokestack. I visited a plant north of Vancouver, British Columbia, to see how this is done. There's this big machine. It's called an air contactor, and it looks sort of like an oversized semi-trailer with a huge fan on top. At the front, it sounds like a waterfall. Chemist and engineer Jenny McCahill told me the liquid is a chemical solution, and as the fan pulls air through the falling solution, it sucks carbon dioxide from the air.
JENNY MCCAHILL: The air contactor is a workhorse. So we're taking the CO2 in the atmosphere, which is about 400 PPM - parts per million...
MCCAHILL: ...Which is about .04%.
BRADY: And this figure of about 400 parts per million - that's important because that's high enough to change the climate but it's just a fraction of 1% of what's in the air. So you have to move a lot of air through this machine to have any effect on the environment.
CORNISH: Jeff, it sounds like you would need many, many more of these machines.
BRADY: Yeah, thousands and thousands of them - and there is a really large plant that's going to be built in Texas, but it would take so many of them, and it's so expensive. And these plants - they create more problems because each plant requires a lot of energy. So, you know, it can be tempting to think that this could be a solution to removing CO2 from the atmosphere and still burn fossil fuels, but it's really not. It's more likely this kind of a plant will be one element of an overall effort to address climate change. It could buy countries more time before the worst effects of climate change start to happen.
CORNISH: You said it's one element, and I want to know. Once the carbon dioxide is captured, what happens to it?
BRADY: You know, probably the most effective thing you could do is put it back in the ground and just leave it there, but that isn't a very profitable business model, so companies are looking for ways to use the CO2 they capture. Kind of ironically, the oil industry can use it. Drillers inject carbon dioxide into oil wells to boost production, which, of course, can lead to more CO2 emissions. You can also use CO2 in products. There's the fizz in carbonated drinks. Several companies in the U.S. and Europe are using captured CO2 for fizzy drinks. And you can grow plants with it. There's a marijuana-growing operation in Pennsylvania that wants to capture CO2 emitted from a natural gas power plant and use it in its greenhouses.
CORNISH: So you've described all these carbon capture projects, but I think we need a reality check. I mean, is this technology that could make a difference in actually slowing climate change?
BRADY: You know, technically, it could, but there's so many questions around the cost and the policies that you need to make it happen. The fact that it's not profitable now - that's really hindering the industry's growth. Still, there are some companies involved in this work. They're getting some attention. There are some federal tax credits coming down that are designed to boost those new projects. And recently, big oil companies have invested in some of these projects. Exxon Mobil is helping one company develop its carbon capture technology. Chevron and Occidental also are investing in projects. And this is important because oil companies have a lot of scientific expertise and money, and it's going to take a lot of both of those things to get this industry off the ground.
CORNISH: That's NPR's Jeff Brady.
Jeff, thanks for explaining it to us.
BRADY: Thank you, Audie. Transcript provided by NPR, Copyright NPR.