We're On Our Way To Planting Synthetic Trees

Published: Wednesday, May 15, 2019 - 12:42pm
Updated: Wednesday, May 29, 2019 - 10:20am
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STEVE GOLDSTEIN: A plan to use synthetic trees to remove CO2 from the air is a step closer to reality. An Ireland based firm is partnering with ASU to deploy the technology. Three years ago, we met Klaus Lackner who was working on the carbon capture technology that would attract carbon dioxide and catch it, allowing it to be disposed of safely or converted into something else. The Environmental Protection Agency says as of 2017, CO2 accounted for more than 80 percent of greenhouse gas emissions in the U.S. Lackner is the director of the Center for negative carbon emissions at ASU, and he recently came back to KJZZ studios to talk with our co-host Mark Brody.

MARK BRODIE: You have a pretty big development here that is ready for commercialization. Remind us what it is that you've been working on and sort of what it is and what it would do.

KLAUS LACKNER: Well I have been working for probably more than 25 years on the idea that we have to think of carbon dioxide emissions as a waste management issue. And by now we have reached a point where we have to clean up after ourselves and probably not just clean up in the future but also take care of the mess we already created. So, to this end we are working on a technology that allows us to pull CO2 back out of the atmosphere, much faster and at a much larger scale than you can reach with just growing trees or the biomass. So we have if you wish synthetic trees mechanical trees, which stand out in the wind and their leaves collect CO2, we take it back off our game and then we have a stream of pure CO2 we can compress and prepare and then deliver liquid CO2 for whatever purpose you had in mind.

BRODIE: So it's basically what you're creating is almost like a magnet for CO2 to take it out of the air and you can do with it something a little more safe than just having it be out there right.

LACKNER: Because if it accumulates in the atmosphere, it causes climate change, it warms the planet, it acidifies the ocean. It just doesn't belong there. And we have created a big mess. Every time you drive a car, for every gallon of gasoline you use, you put 1 pound of CO2 into the atmosphere. So we say we can clean that up again. Ours is the first step to actually develop a technology, which is like you said a magnet or a filter for CO2, just like the tree standing in the wind. And it takes a little bit of the CO2 out ,we take more of that CO2 out, and then we can put it in a safe place. We can dispose of it. We can put it underground. We can do lots of things, but we can also close the carbon cycle. So if you have lots of photovoltaic energy, as we are getting here renewable energy, you can take the excess, which you have at some parts of the day, and use that energy to break up CO2, to break up water, and now you have hydrogen and carbon monoxide, which you can convert of waste technology, which has been around since the 1920s, into any fuel you like.

BRODIE: So your synthetic trees are moving toward commercialization. Does that mean that we could soon see forests of synthetic trees out there somewhere collecting the CO2 out of the air?

LACKNER: Yes, not overnight but over a few years. That's the idea I think in order to have impact, a place like ASU has to then team up with people who come from the outside and say we can commercialize that. And so we may see within a year that prototypes are starting to be built and then we move from there to wind farms. Wind farms, which don't collect energy like your conventional wind farm but they collect the CO2 to then feed into whatever use you have, either making fresh fuels or to dispose of it safely and permanently.

BRODIE: Well are there particular geographical places that maybe in your mind do you think would be better to be trying this out at least at the beginning?

LACKNER: Well we like it here in Phoenix because at least one version of our system likes it where it's dry. On the other hand, we're dealing with a group in Ireland so we want to be flexible about that. And so we have been doing some thinking of how to use other solvents, which are not sensitive to that. So we can we can figure that out. The main important thing, which the company is building on, is the contractor. It's the equivalent of the tree. You can think of this like a column, think of the old-fashioned vinyl discs, which we are sort of forming stacks. Now you make a stack 150 high, and when you pull on that stack from the top, it sort of expands outward like a tall column, which is maybe 30 feet or 10 meters tall. And it stands out in the wind and the air can blow between those discs, and the disks themselves are the equivalent to the leaf. So on top and bottom, they will bind the CO2 and when it comes out on the other side, the air it has a little less CO2 than when it came in. And after about 20 minutes, that's the goal, the disks are loaded and then the whole stack of disks is lowered into a drum at the bottom. The lid closes on this drum, and then we regenerate.

BRODIE: Do you have a sense of how many of these columns these synthetic trees would need to be in a particular place to make a difference? Like are you envisioning there'd be one here and spread out or ... ?

LACKNER: It will likely be a forest, right. Because you need a lot of them to make what nearly one would say to me, hey to make CO2. Right.

BRODIE: So different analogy there, yeah.

LACKNER: Different analogy. So, in effect the columns we designed they are about 5 feet in diameter and 30 feet tall. I need about 12 of them. So a little fence to get a top. Now if you really wanted to keep up with current emissions, you would need a 100 million of those clusters of 12 in order to remove 36 billion tons of CO2, which is what we are currently emitting. Now, I don't think we would do that because you could avoid a lot of CO2 emissions in the future. Now that's a huge number but it's not so huge that you couldn't do it if the last 10 years you would have to build 10 million clusters a year. We built 80 million cars and trucks a year. So I think you can reach this scale if you set your mind to it.

BRODIE: Is it safe to say do you think that the potential of this technology to remove CO2 from the air and all of the other things that come along with that is really only limited by the number of these synthetic trees that can be manufactured and planted or put up somewhere?

LACKNER: I think that's correct. What got me interested in this type of technology is that it ultimately has no serious limits of how far you can scale it. On a smaller scale, I think it's the cheaper option, and we should definitely make it happen. If you have waste biomass, it's the smart thing to do. But if you ask can we get to the scale we need to get to, then I think you will need direct air capture and what motivated me to work on that is exactly that observation. It does scale. And the big question is can we get it to a price where it's affordable. And it looks like like we have a close to this. And we now have a commercial partner who says yes we can push forward on this and actually put this into the market and we can grow this. And if if the demand grows because we understand the climate problem, we are ready to do it. That's that's the message all right.

BRODIE:  That's Klaus Lochner, director of the Center for Negative Carbon Emissions at ASU. Klaus, thanks a lot for coming in.

LACKNER: Thanks for having me. It was a delight to be here.

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