Carbon capture needs to scale up to make a dent in the climate crisis
Jan 25, 2023

Carbon capture needs to scale up to make a dent in the climate crisis

The technology would need to remove millions of tons of CO2 a year to make a difference, says Aniruddh Mohan of Princeton University.

A plant in Iceland recently became verified as the first large-scale facility to remove carbon dioxide from the air on behalf of corporate clients paying to reduce their carbon footprints.

The Icelandic facility is run by the Swiss startup Climeworks and uses a process called direct-air capture. DAC uses vacuum-like machines to pull air into the plant where the carbon is filtered out. Clean air is returned to the atmosphere and the collected carbon is buried underground.

The technology could be key to averting the worst of climate change, said Aniruddh Mohan, a postdoctoral fellow at the Andlinger Center for Energy and the Environment at Princeton University. He spoke to Marketplace’s Meghan McCarty Carino about the promise and problems of direct-air capture.

The following is an edited transcript of their conversation.

Aniruddh Mohan: We’ve kind of locked ourselves into a series of bad options right now in terms of the climate crisis. We have legacy emissions that we need to deal with, and we’re already about 1.2 degrees of warming compared to pre-industrial levels. We don’t see the likelihood of getting to net zero globally anytime soon. So we’re going to have these continued emissions that we need to account for in some way, and at the same time, we need to deal with historical emissions. So direct-air capture is a way by which we can reduce carbon dioxide levels overall. There might be sectors that are harder to decarbonize, such as heavy industry or heavy transportation, and we might need this direct-air capture to account for those residual emissions. And the second thing is dealing with our historical emissions that we’ve produced over the last 100 years.

Meghan McCarty Carino: Is this type of direct-air capture technology scalable?

Mohan: It remains to be seen. The challenge with DAC is that it has very poor thermodynamics. Carbon dioxide is only about 0.04% by concentration of air, so imagine you’re hoovering your entire house just looking for a single strand of hair. It’s a very energy-intensive process, and that means that you need a lot of clean energy to do it, because if you use fossil fuel energy, then obviously you’re not really doing anything to reduce CO2 levels overall. The Climeworks facility in Iceland — that’s one of the companies that’s developing this technology — they have the largest facility in the world currently. And that facility is capturing about 4,000 tons of CO2 per year. This will need to be scaled up by several orders of magnitude in order to actually contribute to addressing climate change. To make a dent in the climate crisis, we’re going to need at least 100 million tons per year of CO2 removal. The United States, for example, emits 16 million tons per day. You get a sense of the scale of where we are currently with the technology and how much further we need to go.

McCarty Carino: In order for facilities like the Climeworks one to be efficient and carbon negative, they have to be built in specific locations. Why is that?

Mohan: In order to get that cheap, clean, abundant energy, there are very few places in the world right now where you can actually locate these DAC facilities. The Climeworks facility in Iceland uses geothermal energy, which gives it the clean energy and the heat that it requires. The other challenge is that you need storage locations for the extracted carbon dioxide, so you need geological reservoirs. Ideally, you want to do this in places — and create an industry and ecosystem in places — which have been historically impacted by the fossil fuel energy system. The Department of Energy has as one of its criteria for DAC hubs that they should be located in places where they can help address some of the issues related to environmental justice and help transition fossil fuel communities.

McCarty Carino: How would you characterize some of the recent developments in DAC?

Mohan: I think it’s exciting. It’s important that we recognize that we need all the technologies we can get our hands on to address the climate crisis. It’s also important to acknowledge that we are in a place right now where we need to make a lot of bets and see what works out. And that’s part of the motivation, I think, for all the funding that’s been allocated to DAC in the last couple of years. I think it still remains to be seen whether this technology can scale to the millions of tons of removal per year that we’re going to need. It’s also currently very expensive. We’re talking about $600 to $800 per ton of CO2 captured. In order for DAC to become a viable technology for carbon removal, those costs need to come down to something like $100 per ton of CO2. There are important developments coming down the pipeline in the next few years, so we might see some of these facilities being launched at a significant scale. We’ll see whether these costs actually come down and whether the energy efficiency of the process can improve to actually be an important player in the climate crisis.

The Wall Street Journal has more details about Climeworks and its DAC operation in Iceland. You can read its story on the startup and see a video about an early iteration of the program that partnered with Coca Cola to captured carbon dioxide for sparkling water.

A Climeworks spokesperson told “Marketplace Tech” that companies like Microsoft, Stripe and Shopify have all bought carbon credits from the startup.

In 2020, Microsoft made a pledge to become carbon negative by 2030, which means it aims to remove more carbon than it emits. But The New York Times reported last year that the company saw emissions increase by about 20% in 2021, demonstrating the difficulty of such corporate promises without carbon removal technology like DAC.

A recent report led by Oxford University, which Aniruddh Mohan contributed to, estimates that all carbon capture efforts around the world are removing about 2 billion tons of carbon dioxide per year. That’s not enough to meet the Paris Agreement goal of limiting climate change to 2 degrees Celsius.

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