In an upcoming report, the Intergovernmental Panel on Climate Change (IPCC) is likely to emphasize the need for a slew of techniques to not just cut emissions, but also suck carbon dioxide from the air. Climeworks, a Swiss startup, today (Oct. 1) opened its third such plant in the world.
Every projection of the warming planet that looks to avoid catastrophic climate change says that we need to cut emissions to zero. But because we’ve been delaying action, the IPCC’s projections are being forced to include “negative emissions” to ensure global average temperatures don’t rise beyond 2°C—a goal set under the Paris climate agreement.
Trees can suck carbon dioxide from the air. But we continue to put so much of it in the atmosphere that we have to deploy other technologies too, such as “direct air capture” (DAC). It involves using a fan to pass air over a surface containing a chemical agent that only reacts with carbon dioxide, then exposing the newly formed compound to heat. That energy breaks the bond, reversing the reaction and releasing carbon dioxide, which can be stored or put to some use.
Climeworks has built and operated DAC plants for more than a year. In May 2017, it launched its first one, capable of capturing 900 metric tons annually, in Zurich, Switzerland. The carbon dioxide captured was fed to a greenhouse, which boosted the growth of the plants inside it. Last year, the company began operating the second, capturing 50 metric tons each year, near a geothermal power plant in Hellisheidi, Iceland. The captured gas is injected underground along with water, where it reacts with basalt rocks and turns into rock in less than two years.
Today, Quartz can report for the first time, Climeworks has launched a third plant in Troia, Italy. Each year, it will capture 150 metric tons of carbon dioxide, which will be converted to methane—a major component of natural gas—and used to power trucks running on “green gas.” The process requires hydrogen, which is produced by splitting water using electricity generated by solar panels. The chemical reaction that converts carbon dioxide and hydrogen to methane also releases heat, which is used by the Climeworks plant in a bid to boost overall efficiency of the process.
The third plant is being funded largely through a research grant provided by the European Union. It’s part of the Store & Go project, which is testing a group of technologies called “power to gas” that can help store energy produced when the sun shines and the wind blows. The idea is that excess electricity is used to run chemical plants that produce methane, which can then be injected into the continent’s extensive gas grid, which has 70 million customers.
To be sure, only the Iceland plant contributes to negative emissions. The other two plants simply recycle carbon dioxide, thus delaying its release to the atmosphere. Also, Climeworks’s technology is still expensive and remains in the realm of research projects. The cost to capture one metric ton of carbon dioxide is between $600 and $800, but it should come down as the startup installs more of these units, according to a Climeworks spokesperson. Another startup, Carbon Engineering in Canada, claims that its DAC technology has already brought the cost down to about $250 per metric ton of carbon dioxide.
We currently emit nearly 40 billion metric tons of carbon dioxide annually. The money spent on capturing any carbon dioxide using DAC is many times the highest carbon tax levied anywhere in the world. So for the technology to become practical and widely used, the cost of capture needs to come down further.