Climeworks: Where Carbon Capture Meets Greenhouse Fertiliser

All around the world, climate change experts and politicans are busy coming up with action plans and strategies to reduce the amount of CO₂ being released into the atmosphere. If the level continues to rise unabated, it’s pretty much inevitable that we’ll fail to meet the crucial international 2 degree Celsius target. Climate change demands that we reduce the concentration of greenhous gases in the atmosphere – and that we do it as quickly as possible. (It’s currently estimated that 10 gigatones of CO2 have to be removed from the atmosphere every year). Not even the most ambitious efforts at avoiding CO₂ emissions will be enough.

One important new aspect of climate change mitigation is therefore so-called “negative emissions” technologies (NETs), a range of different techniques that remove greenhouse gases from the atmosphere. Last month, Swiss company Climeworks inaugurated a new air capture plant that could help. Consisting of a wall of jumbo-sized air filters, it capture and stores CO₂ as a pure gas, meaning that at as well as successfully removing it from the atmosphere, it can then be sold off for use in a variety of different industries, including, in this case, agriculture. The plant is strategically located right next to greenhouse, where the CO₂ collected is used to fertilise plants (which of course, thrive when given a generous supply of carbon dioxide).

How does the Climeworks filter work?

The process used in Climeworks’ plant is called “direct air capture” (DAC) and is said to be able to remove far more CO₂ per acre of land used than trees and plants – in this case up to 900 tons each year. The Zurich plant is made up of 18 CO₂ collectors stacked on top of each other, that suck in air and using a special chemical filter, separate off the CO₂ and store it. Once a filter has been completely saturated with CO₂ it’s heated in a vacuum to 100 degrees, which causes the CO₂ molecules to be released from the material. It can then be stored temporarily as a pure gas. The collectors are carefully aligned with one another so that the individual filters are constantly in different stages of the process.

The location was chosen specifically to ensure that the running of the filters is sustainable too – the roof of a waste incineration plant. 80 per cent of the energy used to run the filters is drawn from the surplus heat that comes from below. And the coolant needed to keep things ticking over is, just like the carbon dioxide, filtered out of the atmosphere by the plant itself.

© Climeworks

“Highly scalable negative emission technologies are crucial if we are to stay below the two-degree target of the international community,” said Christoph Gebald, co-founder and managing director of Climeworks. “The DAC-technology provides distinct advantages to achieve this aim and is perfectly suitable to be combined with underground storage.”

The 40 experts that make up the current Climeworks team have an ambitious goal: by 2025 they want to have filtered one per cent of global CO₂ emissions out of the air. The plant in Switzerland is serving as a sort of test run for this ambitious objective, aiming to convince the sceptics that the plant is both practical and profitable. But if they’re going to meet their goal of one per cent of all global emissions, they’ll have to build another 249,000 filters first.

For more information, check out the video below.

This article is a translation from the original article which appeared on RESET’s German-language site.