If solving the problem of climate change was a 100-piece jigsaw puzzle, systems that suck C02 out of the air might make up one or two pieces. But as a warming planet and rising global emissions loom large, there are many who believe this unproven technology will have an important role to play – the UN's Intergovernmental Panel on Climate Change (IPCC) among them. Climeworks is a Swiss company at the vanguard of this technology, and having just completed a year-long pilot project collecting C02 at the world's first negative emissions power plant, is rather optimistic about the way things are headed.

Is carbon capture a good idea?

The idea of removing carbon dioxide from the air has long been a controversial one. A range of technologies have been bandied about as a way of achieving this, including planting monumental amounts of trees to remove C02 biologically through photosynthesis, carbon sequestration where it is pulled from the chemical processes in power plants before it enters the atmosphere and pumped into underground reservoirs, and direct air capture (DAC), where it is collected from the ambient air.

The trouble is, none of them have been proven to be economically viable on any kind of meaningful scale. Beyond that, experts worry that pursuing these technologies will do more harm than good. The danger is that a great deal of the world today leans on burning fossil fuels and pumping out C02 to keep things ticking over. If direct air capture systems become cheap, reliable and widespread, what incentive would there be to change?

On the other hand, drastic times call for drastic measures, and the startling report published by the IPCC this week says the world will need to rely on these types of technologies to avoid dangerous levels of global warming. Prepared by 91 authors from 40 different countries, the report states that limiting warming to 1.5° C (2.7° F) above pre-industrial levels will involve fast and far-reaching changes in almost every aspect of society. We'd need to cut C02 emissions by 45 percent by 2030, and eliminate them entirely by 2050.

"This means that any remaining emissions would need to be balanced by removing CO2 from the air," the scientists say, before going on to note that the effectiveness of carbon removing techniques are unproven at scale and may involve risks for sustainable development.

True believers

Christoph Gebald and Jan Wurzbacher, two engineering graduates from ETH Zurich, founded Climeworks in 2009 on a mission to make carbon capture economically viable. Its DAC systems work by using huge fans to draw ambient air through an integrated filter material that selectively captures only C02. Once the filter is full, the C02 is heated to 100° C (212° F) and then cooled to 45° C (113° F), allowing it to then be used for a variety of applications, such as carbonating beverages, creating other climate-neutral fuels and certain types of agricultural materials.

It took some time, but in 2017 Climeworks opened its very first commercial plant, and the world's first carbon capture plant that sells its product to a customer. Sat atop an incineration facility in Hinwil, Zurich, the system uses waste heat generated by that facility to bring the captured carbon up to the required temperatures, and pipes the finished product directly to a nearby greenhouse where it is used to help grow vegetables. Climeworks says the Hinwil plant captures 900 tons of C02 every year.

There are many promising possibilities when it comes to turning captured C02 into useful products, ranging from concrete to solar fuels to carbon nanofibers for high-end sports gear. But our demand for energy generated by fossil fuels far outweighs the market demand for captured carbon. Humans pump 30 to 40 gigatons of C02 into the air every year alone, with a single gigaton equal to one billion tons. So for carbon capture methods to really put a dent in the problem, the C02 simply needs to be locked away somewhere. For good.

Capturing carbon and storing it underground has long been touted as an option, but storing the gas in these reservoirs carries the very real risk of leaks. Since 2007, scientists working on the CarbFix project have been exploring how the gas can be made to react with certain rocky material underground and turn into solid minerals, a process thought to take hundreds or even thousands of years.

More specifically, they've been pumping it into the basaltic rocks in Iceland's geothermal fields to try and fast track this process. And, in a hugely significant breakthrough in 2016, they succeeded. By using captured carbon to create carbonated water and pumping that water into underground wells, the liquids reacted with elements like calcium, magnesium and iron to form solid carbonate minerals. It was found that more than 95 percent of the C02 had been converted, and astonishingly, did so in less than two years.

A power plant that cuts carbon emissions

One year ago, Climeworks joined forces with CarbFix to conduct a pilot project at ON Power's Hellisheidi geothermal power plant near Reykjavik, the largest power plant in Iceland and one of the largest in the world. The plan was simple, capture carbon from the ambient air using Climeworks' system and palm it off to the CarbFix scientists, who would convert it into carbonated water and pump it underground to become basalt rock.

Being a geothermal power plant, Hellisheidi's carbon emissions are around 99 percent less than that of a coal-fired facility, which presented the team with an opportunity to create the world's first "negative emission power plant." That may have been true but only for a fleeting moment or two, because as Climeworks spokesperson Martin Jendrischik explains, it was anything but a smooth ride.

"Freezing temperatures combined with high humidity was one of the challenges," he tells New Atlas. "But there is also a high concentration of sulphur in the air, which is also a special hurdle to overcome. Climeworks changed some electronic parts to get around the problems caused by these conditions."

After a steep learning curve and a series of improvements along the way, Climeworks was ultimately able to keep the DAC system running for several months without failure. But with just a single collector on site, the carbon captured with the system fully functioning was a negligible amount – around 12.5 tons over the three months, according to Jendrischik.

"The next step will be to scale up the plant so that several thousand tons of CO2 can be captured and stored underground per year," he says. But after ironing out some kinks in the harshest of conditions, the team harbors far grander ambitions than that.

"At sites like ON Power's Geothermal Park in Hellisheidi we have the potential to remove several hundred thousand to even millions of tons of CO2 annually from the atmosphere," says Dr. Edda Sif Aradóttir, Deputy Managing Director at Reykjavik Energy. "Together with ON Power and Climeworks we are currently planning the next scale-up steps for further increase DACS capacity at our site."

CarbFix's approach is particularly promising, not just because it greatly fast tracks the process of turning C02 into solid material, but because basalt happens to be the Earth's most abundant rock type. This opens up many opportunities to replicate the CarbFix approach elsewhere, with the USA, Middle East, Africa and even the ocean floors all possibilities.

"The storage capacity is such that, in theory, basalts could permanently hold the entire bulk of CO2 emissions derived from burning all fossil fuel on Earth," says Dr. Sandra Snaebjornsdottir, a geologist working for CarbFix.

A drop in the ocean

The technologies championed by Climeworks and the like won't be putting a dent in the global emissions anytime soon. The company has just opened up another demonstration DAC plant in Italy, which it expects to collect 150 tons of C02 each year. The company's stated mission is to capture one percent of global carbon emissions annually by 2025. The magnitude of this undertaking is not lost on Jendrischik.

"To do this, we will need 250,000 plants like the commercial plant in Hinwil, or 750,000 shipping containers full of CO2 collectors, the same number of containers to pass through Shanghai harbour every two weeks," he says.

Which brings us to the cost. Carbon capture and storage remains prohibitively expensive, and no matter how many fizzy drinks are made with Climeworks' product, there will need to be serious legislative shifts that incentivize carbon removal on a grand scale. At present, it costs the company around US$600 to capture a single ton of C02, though the company is confident of cutting this figure to around $115. "For these cost reductions, Climeworks has a clear plan and knows what has to be done," says Jendrischik.

"Deployment of DAC on a mass global scale is something the global economy can handle," he continues. "Long-term, Climeworks' technology has the potential to remove CO2 from the atmosphere at a gigaton scale, something which will definitely have the ability to help reverse global warming."

As part of its business model, Climeworks plans to offer emissions removal as a service to the public in 2019, allowing anybody to reverse their emissions if they wish. You can hear from the company's founders in the video below.

More information: Climeworks

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