To date, carbon capture and storage systems, which have sought to divert and bury carbon dioxide emissions from power plants and industrial facilities, have been controversial. Often associated with the oil and gas industry, these systems are seen as an expensive and complicated solution that may only help to postpone the inevitable shift to renewable energy. But Orca, a new facility in Iceland by Swiss firm Climeworks and Icelandic startup Carbfix, promises to de-couple carbon capture and storage from fossil fuels and instead scrub excess carbon dioxide directly from the atmosphere.
Using a set of fans and filters packed into boxes the size of 40-foot shipping containers, this new facility is expected to remove 4,000 tons of carbon dioxide from the air annually, injecting it deep into the ground, where it will eventually mineralize into rock. According to the U.S. Environmental Protection Agency (EPA), that amount of carbon dioxide equals annual emissions from around 870 cars. Climeworks hopes to remove 500,000 tons by 2030 and eventually 300 million tons a year, but this would still only account for 1 percent of global emissions. For reference: in 2020, 31.5 billion tons of greenhouse gases were emitted.
At the opening ceremony of Orca, Icelandic Prime Minister Katrin Jakobsdottir said: “this is indeed an important step in the race to net-zero greenhouse gas emissions, which is necessary to manage the climate crisis.”
Orca, which in Icelandic is phonetically the same as “energy,” is entirely powered by renewable energy. According to The Guardian, the system uses fans to push air into a collector with filters that separate out the carbon dioxide. As the filter material fills with CO2, the gas is heated to approximately to 212°F (100°C), which enables concentrated CO2 to be separated out, mixed with water, and injected 1,000 meters (3,280 feet) underground in basalt caverns, where the mixture becomes hydride of sulphur (HS2) in approximately four months and then dark grey rock 20 months afterwards. The system is expected to work well with the geology of Iceland, but it’s unclear whether it can succeed in other geologies, and what amount, type, and quality of water is required to inject and mineralize the gas.
Another issue is the comparatively high-cost of the nascent technology: about $600 to $800 per ton of carbon storage, which is much higher than the $100 to $150 needed to make the system cost-competitive without subsidies or a corporate benefactor. The companies involved believe that as they scale up their facilities, costs can be reduced to $200 to $300 per ton by 2030 and half that again by 2040.
The Washington Post states that injecting CO2 into the ground is just one way to handle excess CO2 captured from the atmosphere. Climeworks’ 15 other installations across Europe harvest CO2 into order to recycle for other uses: It can be mixed with hydrogen to make fuels. Farmers can feed their plants CO2. Soda companies can use it to create bubbles.
The United Nations Intergovernmental Panel on Climate Change (IPCC) argues that methods to actively draw down greenhouses gases from the atmosphere will be required to achieve the goal of limiting warming to 1.5°C. The International Energy Agency contends that carbon capture and storage systems will need to pull 1 billion tons out of the atmosphere by 2050 to be viable in helping to achieve that goal. While Orca may increase interest and investment in scaling up machine-based carbon capture and storage, another solution that offers so many additional benefits shouldn’t be forgotten — trees.
An average tree absorbs an estimated 48 pounds of CO2 per year, so by the time it reaches 40 years old, it has stored a ton of carbon. Given the relatively long time frame for trees to sequester carbon and the world’s more immediate carbon draw down needs, many scientists and environmental groups have called for planting vast forests at a much faster pace. The United Nations’ trillion tree campaign, supported by the World Economic Forum and American Forests, seeks to “conserve, restore, and grow” one trillion trees around the world by 2030.
Scientists are also looking more broadly at tree planting as a tool to restore forest ecosystems and store more carbon terrestrially over the longer term. A 2019 study in the journal Science found that “ecosystems could support an additional 0.9 billion hectares of continuous forest. This would represent a greater than 25 percent increase in forested area, including more than 200 gigatonnes of additional carbon at maturity. Such a change has the potential to store an equivalent of 25 percent of the current atmospheric carbon pool.”
So trees alone are also not the answer to the climate crisis, but they offer many other ecological and human health benefits beyond their ability to naturally capture and store carbon — supporting sustainable water cycles and biodiversity, providing shade, and cooling and cleaning the air. Many trees also offer usable wood: the only building material that stores carbon.
Landscape architects plan and design parks, plazas, and streetscapes, increasing the percentage of communities that are forested. A key next step is to bring the benefits of these beautiful carbon sinks to all communities in an equitable way. American Forests states that 522 million trees need to be planted and protected in U.S. cities alone to achieve tree equity.