TIL about carbon capture

Hello and welcome to Today I Learned Climate, the show where you learn about climate change from real scientists and experts. I'm your host, Lar Hesse Fisher, with the MIT Environmental Solutions Initiative. We're back with our next episode in our series on energy and climate in partnership with the MIT Energy Initiative.

So far this season, we've talked about ways our electricity system could burn fewer fossil fuels so that the carbon natural Trapped in oil or coal or natural gas stays underground where it can't warm our atmosphere. But today we'll be talking with two members of the MIT Energy Initiative about a technology that actually doesn't try to replace fossil fuels. My name is Howard Herzog. I'm a senior research engineer in the MIT Energy Initiative.

In about a month's time I'll be celebrating my thirtieth anniversary uh at the Energy Initiative or its predecessor, the Energy Lab. I'm Brad Haker. I'm a uh professor of Earth, Atmospheric and Planetary Sciences. And uh in addition to being a professor, I'm the co-director of the MIT Energy Initiatives Low Carbon Energy Center on carbon capture, utilization, and storage.

That's right, they both work on something called carbon capture utilization and storage, abbreviated as C C U S, or sometimes just called carbon capture, like we'll call it today. The problem for climate change is the emission of CO two into the atmosphere.

So when you burn fossil fuels, you create CO two. The idea in carbon capture is that CO two that's created by the burning of fossil fuels, you stop from going into the atmosphere. And you do that by Capturing it, and then you put it somewhere other than the atmosphere. So why would we even consider this? Well, as we've heard earlier in this series, adding clean energy sources like

Solar, wind, and nuclear comes with a lot of complications that we need to work out. In theory, carbon capture lets us use the energy system that we have now, but removes the CO2 emissions from that system. The problem with climate change isn't fossil fuels. The problem is the buildup of greenhouse gases and the

And so what we want to do is look at solutions that reduce the amount of greenhouse gases we're putting in the atmosphere. If we do that by using less fossil fuels, which I think is gonna be part of the solution, so be it. But It doesn't mean that we can't continue to use fossil fuels if we have the technology to use them without putting their emissions into the atmosphere.

So today we'll be diving into how carbon capture works, what we're supposed to do with all of this CO2 once we capture it, and just how realistic this is as a way to help slow climate change.

But let's start with the basics. Because power plants and factories emit so much carbon dioxide in one place, most carbon capture happens there, from the flue gas that comes out of their smokestacks. Here's Professor Hager. The method of capturing carbon dioxide that has been used for the longest is to run the flue gas.

Through a solution of uh chemicals called amines, the um uh the carbon dioxide dissolves in the amines. Then you compress it to turn it into basically a liquid, a high pressure liquid. Technically it's it's called uh a supercritical fluid, but it it basically acts like a uh liquid and then you can put it in a pipeline and uh you can put it down a well into the earth. And the place that right now is the biggest opportunity to store the CO two is in deep underground formation.

Engineers look for just the right places to do this so that the CO2 can't leak back into the atmosphere or into our groundwater. So we can think of a good reservoir candidate for storing this stuff as being a layer of shale called the caprop to keep the uh fluids in place and then underneath it uh a a layer of sandstone to provide Empty space to put the CO two in.

Originally I imagined these underground caves that the fluid CO2 was poured into, but actually it's injected into a rock, which kind of absorbs the CO2. The way to think of it is think of uh you're at the beach and you have a bucket of sand and you can put water into it and the water goes in the uh pores between the sand. The CO2 then sits there, in the same way that oil has been sitting in these kinds of spaces underground naturally for millions of years.

And if this sounds like science fiction, well, actually it's already happening. There are around 20 facilities using carbon capture and storage around the world. Although most of them aren't power plants. They're other industrial plants like natural gas processors or steel or fertilizer plants. And some of them have been running for a long time. The first really serious project is called uh Schleipner, run by the Norwegians. So in 1996, they started producing sourgas.

uh cleaning it up, removing the carbon uh dioxide, and injecting it into the subsurface underneath the North Sea. And for the last uh twenty-three years since the plant started, uh they have been injecting about a million tons of carbon dioxide a year into the uh subsurface. A million tons of CO2 is about the same that 200,000 US cars emit in a year. But burying this CO2 is not our only option for dealing with it.

Recently there's been a lot of interest in using the carbon dioxide as an intermediate product. It can be used to make plastics, make feedstocks for plastics, and it can even be combined uh with hydrogen to make uh for example jet fuel. The more useful stuff we can make out of CO2, the more reason that companies will have to capture it. Because right now, there isn't really a big market for this captured CO2.

At best it's gonna be a niche solution. The amount of CO two that we are producing from energy use basically is so much larger than markets for these a lot of the products people are thinking of, you're still gonna need to put it in underground reservoirs if carbon capture is going to be adopted at a large scale. What does large scale really mean? Well, let's imagine that we only capture and store one tenth of the CO2 that we're emitting today.

That would be about as much liquid as all of the oil consumed worldwide. and oil is a massive industry, served by huge tankers and storage depots and hundreds of thousands of miles of pipelines. It would take a lot to repurpose or build new infrastructure for moving around CO2. And if you're a power company or a steel manufacturer, you might be wondering why you would pay for it.

Which brings us to one of the big challenges for carbon capture. It's pretty expensive. There's additional expense that you need to build the uh facility to do this, and then it takes energy to do it. So the uh increase in you know cost of electricity coming down the power line to the consumer uh is on the order of uh 30 to 50 percent. And at the moment, there's not much of an incentive for power companies to take on that extra cost.

In order to promote the capture of carbon dioxide, you need some sort of economic incentive to do that. So uh you can have a carrot or you can have a stick. And the carrot, which is being held out right now, is the uh basically tax uh rebate. Yeah, actually here in the US, we offer companies a tax credit for capturing their carbon emissions. Right now it's about$50 per ton of CO2, but it's not really high enough to retrofit all of our fossil fuel power. So that's the carrot and the stick.

The other side is uh putting a price on carbon and so if that's high enough, a company will, you know, voluntarily capture and and sequester uh its carbon dioxide. We did a whole episode on carbon pricing in our first season, so check that out to understand how a carbon price would work. The thing that you're hearing here is that capturing and storing CO2 at our current power plants is possible. But we either need to decrease the costs of doing it or increase the incentives.

The policies that we choose can make a huge difference to companies deciding whether or not to invest in something like carbon capture. Technology doesn't happen in a vacuum. You know, innovation doesn't happen in a vacuum. You you need to to create the markets and that's uh a political thing and and See I think if you had a carbon tax.

create innovation and there's a lot of room for innovation in this area, but there's no silver bullet in uh dealing with climate change. There's no one solution that's going to provide the answer.

If it becomes cheap enough, carbon capture could be a long-term solution for many power or manufacturing plants. Or its role could be to help us cut emissions immediately until we solve the challenges with wind, solar, and nuclear power or energy efficiency. I see this as a uh a a strategy that will bridge through the next three decades. the next twenty to fifty years, I hope that cheaper sources of of electricity, of clean electricity will be developed.

So, carbon capture is one more tool that we can add to our clean energy tool belt. And it's just like all the other technologies we've explored in this series, in that it's powerful, but with its Advantages and disadvantages. And none of them are able to do the job. There is a lot more to learn about We've left some links in the show notes and on Twitter to places where you can learn more, including a couple of episodes of the MIT Energy Initiative. Next up on TIL Climate, we're looking at Mm.

Stay with us. A quick shout out to Amy Lee Wee, who left us a review on Apple Podcasts. Amy Lee Wee says, super informative podcast that breaks down really complex topics into small bytes. And does so without placing the blame. Keep up the good work. Thanks, Amy Lee Wee, we appreciate it. We invite you to leave us a review on Opple Podcasts as well, or wherever you're listening from today.

Today, I Learn Climate is brought to you by the MIT Environmental Solutions Initiative. Thank you to Brad Hager and Howard Herzog for talking with us, and thank you for