Climeworks Captures Double the CO2 for Half the Energy

The world’s first megaton carbon capture site will join a growing field

4 min read

A rendering of Climeworks new direct-air capture technology.

The Zurich-based startup Climeworks is developing a direct-air capture (DAC) plant, whose prototype is expected by decade’s end to remove a megaton of carbon from the atmosphere per year.

Climeworks

The geoengineering debate—which, in part, concerns pulling back carbon that’s already in the atmosphere—has been hindered to date by the lack of scalable tech. The Swiss startup Climeworks is hoping to help turn the tide.

The Zurich-based company has just unveiled the latest generation of its direct-air capture (DAC) technology, which it says will help remove millions of tonnes of carbon dioxide a year by the end of the decade.

Climeworks has, in fact, already made a name for itself by building a series of large-scale carbon capture plants in Iceland. The company switched on a facility dubbed Mammoth last month, which is now the world’s largest DAC plant and will ultimately be able to pull 36,000 tonnes of CO2 out of the air annually.

But speaking at the opening of the Climework’s annual Carbon Removal Summit in Zurich yesterday, co-CEO Jan Wurzbacher noted that according to projections from the Intergovernmental Panel on Climate Change (IPCC), the world will probably need to be removing between 6 billion and 16 billion tonnes of CO2 a year by 2050.

“If we look at our scale-up curves—our growth rates that we need between now and 2050, to achieve those goals—those rates are very similar to the ones that solar PV and wind have shown over decades as well.” —Jan Wurzbacher, Climeworks

While that remains a distant goal, the company has taken a modest step in that direction with the announcement of the third generation of its DAC technology. The new system features a revamped cubelike design and a reengineered sorbent (the material used to absorb CO2), which Wurzbacher said can capture twice as much carbon dioxide as the previous design. The new system also uses half the energy, while the materials are projected to last three times as long—all of which cuts overall costs by 50 percent.

“So it’s really a leap forward from the technology side,” Wurzbacher said. “And all of this will be the basis for all future Climeworks plants to be built. In particular, for our next installation that is planned in the United States in Louisiana within the so-called Cypress Hub, which should be the first megatonne [one-million-tonne] carbon dioxide removal hub in the U.S.”

A Different Kind of Megatonne

The Project Cypress DAC Hub, which is being funded by the U.S. Department of Energy, is a partnership between Climeworks, nonprofit technology-development company Battelle, and carbon storage firm Heirloom. The plant is due to come online in 2027 and will initially be capable of removing 250,000 tonnes of CO2 a year, with the figure rising to a megatonne by the end of the decade.

That is a big jump from Climework’s current capacity, and Wurzbacher said the company has been working hard to optimize its technology to meet the demand. Its plants work by using giant fans to draw air over beds of sorbent, which are housed in large “collector units.” Once the sorbent has become fully saturated, these units are shut and then heated to release the CO2 again so it can be stored deep underground.

Rendering of an aerial view of a Climeworks carbon capture site.To make DAC plants work at scale is a massive engineering challenge, the company says. But the challenge is also not out of line with other scale-ups, like recent booms in the solar and wind industries. Climeworks

“The art of designing direct-air-capture technology is how can we contact the airflow as efficiently as possible with our filter material,” said Wurzbacher. For the latest iteration of its technology, the company has created a new “structured sorbent,” whose geometry has been tweaked to increase the surface contact with the air. This halves the time to either absorb or release CO2, making it possible to capture twice as much CO2 in a given time and to reduce significantly the amount of heat required to release the gas.

Wurzbacher said Climeworks researchers have also reworked the chemistry of the amine-base sorbent they use, which should significantly increase the materials’ lifetime. “[Inferring from] current results from our long-term testing and our accelerated aging testing, we assume that we’ll be able to have material which lasts about three times longer than the current material,” he said.

Reengineering the Carbon Collector

Climework’s engineers have also completely reworked the layout of the collector units. At the company’s Mammoth facility, collector units are currently installed in three-tiered racks that jut out from the main building. But the third generation will shift to a cubelike design, with four walls of collectors surrounding a central shaft with multiple fans positioned at the top. The fans pull air through the collectors and then expel it upward, which Wurzbacher said prevents already decarbonized air from being recirculated through the collectors. The new design also reduces the overall cost of the units, he adds.

While the company has yet to build a complete cube, Wurzbacher said it has installed and tested a full-scale collector unit featuring the new sorbent at a test site in Basel, Switzerland. The company didn’t provide concrete figures on exactly how much carbon the units are capable of removing, or on energy requirements, or current costs. But chief operating officer Douglas Chan said the company was targeting $400 to $600 a tonne by 2030, dropping to $150 to $250 by 2050.

“As we increase the capacity of our plants, economies of scale from the process equipment will help to drive efficiencies and cost,” Chan said. “As we repeat more and more of these cubes and more and more of these modules, we are able to improve our supply chain as well.”

The company said that, in addition to Project Cypress, it is actively developing megatonne-scale facilities in Canada, Norway, and Kenya. And when questioned on the financial viability of pulling billions of tonnes of carbon out of the atmosphere, Wurzbacher pointed out that a lack of climate action meant humanity was short of alternatives. He also pointed out that, although creating an entirely new industry from scratch might seem like a tall order, it’s been done before in the recent past.

“If we look at our scale-up curves—our growth rates that we need between now and 2050, to achieve those goals—those rates are very similar to the ones that solar PV and wind have shown over decades as well,” Wurzbacher said. “So there’s evidence that industry can do this.”

The Conversation (1)
ROBERT POOR
ROBERT POOR07 Jun, 2024
M

If the Climeworks (or any DAC) technology could be scaled to be _small_ enough, it could piggyback atop existing cooling fans on data centers and HVAC systems. Why spin an extra fan when there are plenty of others that are already spinning?