How this groundbreaking carbon removal facility could help fight climate change

It's known as Climate Restoration (CR), a strategy being pursued by Climeworks AG, a Swiss company specializing in Direct Air Capture (DAC) technology (where an industrial, selective filtration process absorbs CO2 from the atmosphere). As we explored in a previous article, climate restoration consists of strategies for removing excess carbon from our atmosphere, which is complementary to adaptation and mitigation strategies.

The company was founded in 2009 by Dr. Jan Wurzbacher and Dr. Christoph Gebald, two mechanical engineers who met while studying at ETH Zurich. The two developed the DAC technology their company relies on as part of their doctoral studies, and as part of the Professorship of Renewable Energy Carriers - an ETH Zurich research program aimed at advancing renewable energy technologies.

The company is best known for its Orca facility, the world's first large-scale direct air capture and storage plant outside of Reykjavík, Iceland. This facility commenced operations in 2021 and consists of eight air collectors that have a nominal capture capacity of 4,000 tons of CO₂ a year. However, their long-term aim is to scale up and build more facilities so that they can capture more than a million tons by 2030.

The company recently raised $600 million Swiss Francs (CHF), equivalent to roughly $650 million, in its latest equity round. With this and future investments, Climeworks plans to expand and create other facilities worldwide. Climeworks' head of technology, Dr. Nathalie Casas, explained to Interesting Engineering (via Zoom) how this fits into a multi-generational plan for change:

"The Orca plant has been designed for 4,000 [tons], but the next plant we are planning for 2023 will be around ten times bigger. We have generation N, which is now Orca, and then we have the next generation (N+1), which my team is working on. The plan is to have a capture capacity of half a million tons a year by 2027. To get there, we will have several smaller plants, but also the evolution of a next-generation big plant. We need to make it more efficient, we need to reduce energy consumption, and we need to make it cheaper."

A global vision

According to the AR6, to ensure that the worst-case climate scenarios do not unfold, humanity must commit to a "carbon budget." In short, we must limit ourselves to producing 420 gigatons (381 billion metric tons) of CO2 or less by 2030. This is about twelve times the current rate of 34.81 gigatons (31.58 billion metric tons) a year and works out to an annual reduction of about 20%. 

If we remain within that budget, the AR6 indicates that we will have a two-thirds chance of limiting warming to 1.5° C in that time. In short, there are no guarantees that our best efforts will prevent the worst from happening. Moreover, these findings confirm that the ecological effects we see today - rising sea levels, disappearing glaciers, shrinking ice caps, increased wildfires, drought, storms, extreme weather, etc. - are going to get worse before they get better.

To make matters worse, even in the most optimistic mitigation scenario presented in the AR6 (SSP1-1.9), we are not likely to prevent some of the more significant impacts from happening. In most models that fall into this scenario, where global CO₂ emissions are cut to net zero around 2050, the world will still exceed 1.5 °C of warming during the middle of the 21st century before dropping below it again by 2100. 

This projection, however, is based on the large-scale adoption and deployment of negative emissions technologies such as bioenergy with carbon capture and storage (BECCS).0Carbon storage is an especially important part of this since it ensures that sequestered emissions do not re-enter the atmosphere. According to research conducted in 2016, the global capacity for CO₂ storage lies somewhere between 5 and 30 trillion tons. 

According to the IPCC data, 10 billion tons (~9 metric tons) of carbon dioxide will need to be removed from the air every year by mid-century to ensure future warming trends do not exceed 1.5 °C. To accomplish this, DAC operations and other BECCS technologies are required. As Dr. Casas explained:

"We need to remove CO2 from the air if we want to stick to the 1.5 Celsius target, so there is no way around it. There are still the mitigation and adaptation [efforts], but if you look at the IPCC reports from two years ago, the projected requirements for carbon removal were much, much smaller. And now it's becoming more and more important. This is also reflected in the money that is being invested into companies in the carbon removal space and the DAC industry in particular. The DAC business is getting more and more attention, and more and more money is flowing into the [technology].

"This reflects scientific findings. Our solution is one of many solutions for the future. We cannot solve the problem alone. We need emission reduction alongside emission removal, even if removal is going to be more expensive than reduction. The solution for the future is a portfolio of many different solutions."

*Based on 2020 data (source)

How does it work?

The DAC process pioneered by Climeworks and its co-founders is quite simple. It consists of modular CO₂ collectors that can be stacked to build machines of any size that selectively capture carbon emissions via a two-step process. First, the air is drawn into the collector by a system of high-powered fans, where it is captured by highly-selective chemical filters.

Second, once the filter is full of carbon dioxide, the collector is closed, and the temperature inside is increased to between 80 and 100 °C (176 and 212 °F). This releases the carbon dioxide, which is drawn off to produce highly-concentrated CO₂ that can then be used to produce biofuels or carbon-neutral materials (such as limestone or carbon composites) for commercial use.

Climeworks focuses on permanently removing the CO₂ in Iceland, the carbon is mixed with water and pumped underground, where it reacts with basalts to become carbonate rock within a few years. The apparatus used to accomplish this at the Orca facility was created thanks to Climeworks partnering with the Icelandic company Carbfix, one of the world's leading companies in rapid underground mineralization of carbon dioxide. 

The process is scalable and adaptable to different locations, thanks to the various sorbents (filter materials) used by Climeworks in their collectors. Casas said:

"We have a portfolio of sorbents. The reason is that different sorbents behave differently in different conditions. Some perform best if it's humid and let's say, temperatures are higher temperatures. Others like it cold and dry, others cold and wet. That's something we learned over the last ten or twelve years. We learned what sorbent works where."

"With the air, it varies quite a lot in terms of humidity and temperature. The sorbent degenerates after a certain amount of time, and we have to replace it roughly every three years. So, if you look at Iceland, you have an average temperature and humidity, which is quite different from conditions in California. We design our operations based on the average humidity and the average temperature."

The entire process is powered by renewable energy, resulting in less than 10% grey emissions (emissions from construction, transport, or storage of materials). This effectively means that for every 100 tons of carbon dioxide captured, at least 90 tons are permanently removed from the atmosphere. In the case of the Orca plant, the operation is powered by geothermal energy, in which Iceland's volcanic activity is used to power turbines that generate electricity.

As Casas explained, it is this combination of clean energy and storage capacity that ensures captured CO₂ will be permanently separated from the atmosphere:

"There are two things you need if you want to remove CO₂ from the air. We need a certain input, which is the air (that is abundant everywhere) and energy to run our plants. As an output, we have CO2. So ideally, our plant sits somewhere where we have renewable energy and a storage site. However, if a place doesn't have both, both renewable electricity and also CO2 can be transported to and from the site."

Compared to other methods for carbon removal (such as afforestation and reforestation), DAC requires the smallest land and water usage. As a result, it is well-suited as a "technological approach" that can augment and function alongside "natural approaches." Both of these must be employed to ensure that climate change disaster is averted.

Building a new economy

Even though Iceland provides ideal conditions for direct air capture and storage, the process can be adapted to any location on the planet where renewable energy and geological storage options are available. In short, facilities could be powered by solar, wind, or biomass energy wherever these sources are in abundance. The technology is also scalable, allowing for operations of varying sizes.

As Casas explained, the latest round of funding will allow for the expansion of their operations in Iceland and beyond. This is crucial if carbon removal technology is to have a significant impact on climate change:

"The funding also reflects the necessity to scale this technology up. Luckily our system is very modular, and the beauty of it is that you can de-risk the technology at a small scale while scaling up. We can build an Orca, which is the biggest DAC plant today, which delivers the captured carbon to customers. However, if you look at the challenge we are facing, it's a very small plant. We need to scale up fast and build more and bigger facilities."

To ensure that the worst-case scenarios don't happen, the IPCC AR6 Report stresses that humanity must commit to removing 310 gigatons of CO₂ from the atmosphere between now and 2100. Accomplishing this titanic goal will require that DAC and similar technologies become operational on a vast and global scale. Herein lies another goal of Climeworks, which is to make the technology more efficient and cost-effective.

"If you think about scaling up, one part of it is to make the technology more efficient, where we use less energy, create a smaller footprint, and make it cheaper," said Casas. "The other thing is the whole supply chain. We cannot do it alone. We need partners who work with us as we are building up an entire industry. And we need to do it fast to be relevant for the climate."

Roadmap to a cleaner future

The ultimate vision of Climeworks, to remove enough CO2 from the atmosphere by 2030 to avert ecological disaster, is consistent with the goals of the UN Environmental Program (UNEP) and the IPCC (which UNEP oversees). It is also consistent with the Global Goals, a set of 17 goals to end extreme poverty, inequality, and climate change by 2030.

This includes Goal 7, ensuring access to affordable, reliable, sustainable, and modern energy for all; Goal 9, building resilient infrastructure, promoting inclusive and sustainable industrialization, and fostering innovation; and Goal 13, taking urgent action to combat climate change and its impacts. In short, the company is looking past the development of DAC technology to create an entirely new energy infrastructure.

And of course, there's also the cooperative aspect of this work, where multiple groups - including those from both government and industry - are committed to working together to promote the transition to clean energy. When it comes right down to it, there is no other way to address climate change and its impacts before it's too late. In the meantime, existing operations need to be scaled up and expanded rapidly.

But of course, this strategy is merely one of several for addressing climate change. As noted, Climate Restoration efforts are designed to be implemented in parallel with mitigation and adaptation strategies. It is also meant to parallel efforts to curb CO2 emissions, such as carbon capture and sequestration/storage (CCS). It is by no means a substitute for sustainable development and making major and lasting changes to how we live.

With this latest round of investment, Climeworks is on track to realize its goal of achieving 1 million tons of carbon removed from the atmosphere by 2030. But as operations scale up and prices fall accordingly, the technology is likely to see widespread distribution. And as Casas reminds us, this goal goes far beyond any single entity.

"I hope that in 2030, there will be several big plants out there," she said. "And I'm hoping that there will be several big plants (not only Climeworks and not only direct air capture) because I think that the challenge is huge. We need to scale up fast, and we can't solve the problem with one company, so we need others to follow."