This is the first in our new Breakthroughs column exploring early-stage technologies and scientific developments that could play a role in corporate solutions to climate change. (The first installment is here.) Email ideas and pitches to [email protected]. 

Carbon capture tends to be a galvanizing topic. There is no shortage of hopeful startups and established companies trying their hand at ways to draw down what's already in the atmosphere and no dearth of skeptics who believe these systems always will be too darn expensive to scale.

Swiss company Climeworks is out to prove the naysayers wrong. Founded by engineers Christoph Gebald and Jan Wurzbacher, who met as undergraduate students, the company this month switched on its second plant designed to filter carbon dioxide emissions directly out of the ambient air. The captured gas will be mineralized and stored in basalt bedrock almost a half-mile under the test site alongside a geothermal power facility in Hellisheidi, Iceland. (It apparently takes about two years for that process to occur.) At Climeworks' first plant in Hinwil, Switzerland, the captured gas is compressed into fertilizer that is being used by a nearby greenhouse.

Our plan is to offer carbon removal to individuals, corporates and other organizations as a means to reverse their non-avoidable carbon emissions.

According to Climeworks, what makes its approach different from other captured capture methods (including the age-old method of planting more trees) are the relatively modest footprint it requires compared with other methods and its minimal use of water.

"The potential of scaling up our technology in combination with CO2 storage is enormous," said Gebald, CEO of the eight-year-old operation. "Not only in Iceland but also in other regions which have similar rock formations. Our plan is to offer carbon removal to individuals, corporates and other organizations as a means to reverse their non-avoidable carbon emissions." 

Here's how it works

The Climeworks system stands about seven feet tall, resembling a huge industrial fan or piece of heating, ventilation or air-conditioning (HVAC) equipment. Each "collector" can suck up 50 tons of CO2 annually out of the atmosphere by using a chemical process to absorb the gas and bind it to filter materials in the system. What happens next depends on who's using the system: it could be stored or converted for some other purpose.

The Climeworks plant in Switzerland uses 18 modules for a total capacity of 900 metric tons of carbon annually. In Iceland, a sole Climeworks collector is being tested as part of a larger carbon capture project called CarbFix run by utility Reykjavik Energy, the University of Iceland, the French National Center for Scientific Research and Spanish consulting company Amphos 21. The project began three years ago, and it already is being used to store 18,000 metric tons of carbon dioxide captured at the geothermal plant.

"We have developed CarbFix at a unique location here in Iceland and proved that we can permanently turn this greenhouse gas into rock," said Edda Sif Aradottir, project leader for CarbFix. "By imitating natural processes, this happens in less than two years. By integrating the Climeworks and CarbFix technologies, we create a solution that is deployable where we have basalt but independent of the location of emissions."

Each 'collector' can suck up 50 tons of CO2 annually out of the atmosphere by using a chemical process to bind it to filter materials.

According to a Climeworks spokesperson, the main goal of the pilot is to gauge how the technology performs in the harsh winter conditions of northeast Iceland and to understand how the systems handle other air impurities, such as sulphur compounds. Aside from the weather considerations, sites around the world in North America, China and the Middle East have similar rock formations where this technology could be installed, the spokesperson said. 

The only game in town, but for how long?

What does it cost to support this process? Climeworks describes its approach as "economically viable." It doesn't disclose pricing details, but founder Wurzbacher recently told Quartz that the company is eyeing costs of about $100 per metric ton of carbon dioxide. 

Considering that the world collectively discharges an estimated 40 billion metric tons of CO2 annually, that's a pretty daunting figure. But if you start thinking about turning this gas into a "product" — for use in carbonated beverages or for chilling food — the math looks better.

The Climeworks cost projections are similar to the numbers marketed by Carbon Engineering, a British Columbia company that is also working on direct air capture technologies. But it's about twice the amount touted by another upstart, Global Thermostat, based in New York.

Both companies are roughly the same age as Climeworks, but so far, neither has reached the same commercial stage as its future, would-be competitor.