Can Kenya become a direct-air-capture hub?

Octavia Carbon, a Kenya-based start-up, has an audacious goal. It wants to become the first company to deploy direct-air-capture (DAC) technology—a method of removing carbon dioxide from the atmosphere—outside the US and Europe.

The hurdles are high. The technology is new and is being used commercially at only two sites in the world. And Octavia needs more R&D before it can advance its process from pilot to commercial scale. Moreover, the technological infrastructure in Kenya is less robust than that of higher-income countries, to say nothing of the financial infrastructure needed to service a DAC venture.

But Martin Freimüller, Octavia’s CEO and founder, says he’s confident the firm will overcome the infrastructure constraints. He’s counting on Kenya to deliver three unique attributes: abundant renewable energy, a local geology that is well suited to the project, and a talented human resource pool that makes the country a competitive place for developing DAC.

With a team of 47 employees, Octavia says it’s the fourth-largest DAC company in the world. The start-up is currently conducting CO₂ removal tests using three machines it has built. If all goes according to plan, the firm will install more than 100 machines in 2024, Freimüller says.

The goal is to scale the machines’ capacity as DAC technology advances. For example, Octavia’s first machines will be capable of removing 100 metric tons (t) of CO₂ per year; a 1,000 t model will follow. Octavia will build the DAC machines, and another start-up—Cella Mineral Storage—will be responsible for storing mineralized CO₂ underground.

“We aim to ramp this capacity in the coming years by deploying more machines,” Freimüller says. Octavia’s long-term target is to permanently remove 1 million t of CO₂ from the atmosphere by 2030.

Before setting up Octavia, Freimüller, an Austrian national, worked in the Nairobi, Kenya, office of the consulting firm Dalberg Advisors, where he gained expertise in CO₂ removal as the firm’s global expert in carbon markets. Freimüller’s stay in Kenya has convinced him that the country has the right attributes to develop a DAC project.

Top on Freimüller’s list is Kenya’s abundant renewable energy resources, which are the source of over 90% of the country’s energy. The country is the leading geothermal power producer in Africa and the seventh largest in the world, but it uses only about 10% of its power capacity. The amount going untapped, Freimüller says, is enough to power Octavia’s DAC plants to mega–metric ton scale.

Although Octavia will use some geothermal electricity, it has tailored its DAC technology to rely largely on unused geothermal heat, according to Diana Maranga, business development lead at the company.

“And in so doing, the company’s DAC electricity requirements are lowered by approximately 85%, meaning geothermal electricity will be needed for only 15% of the DAC operations,” Maranga observes.

The world’s first large-scale DAC facility, operated by Climeworks in Iceland, removes 4,000 t of CO₂ per year, at a cost of $600–$800 per metric ton. The CO₂ is stored underground, where it reacts with basalt, creating carbonate minerals.

Just as Octavia plans to do, Climeworks uses geothermal power and waste heat, meaning its operations have a net-zero carbon output. Successful CO₂ sequestration using basalt has also been demonstrated by the Wallula basalt sequestration pilot project in the US.

It so happens that the geology in Kenya’s Great Rift Valley offers CO₂ storage characteristics similar to those in Iceland. The Rift Valley is also the location of the country’s geothermal plants.

Maranga says Kenya’s talent pool has been instrumental in developing the technology at a faster rate than Octavia’s DAC-industry peers. All of Octavia’s staff members, except Freimüller, are Kenyan. Two staffers have specific experience with DAC developed during study for their engineering degrees. The rest of the engineering staff is composed of professionals with degrees in fields such as chemical analysis and mechanical and electrical engineering.

Freimüller hasn’t disclosed much about Octavia’s technology, saying the firm is in the process of obtaining patents. He does say that it traps CO₂ with a solid amine sorbent developed by Octavia’s R&D team.

Experts say the most advanced DAC processes are based on either solid sorbents or liquid solvents.

Climeworks and the start-up Global Thermostat use solid sorbents, which consist of a high-surface-area support material featuring amine groups that adsorb CO₂ through a reversible chemical interaction, explains Alex Crutchfield, an associate research analyst at the consulting firm Cleantech Group. Amines, usually dissolved in water, are already used industrially to remove CO₂ and hydrogen sulfide from natural gas.

Another prominent DAC firm, Carbon Engineering, uses a liquid-solvent-based approach that relies on the conversion of potassium hydroxide to potassium carbonate.

Despite Octavia’s energy-saving innovations, the cost of the project remains a challenge. Freimüller says the investors that fund climate technologies like DAC usually look to companies in the US and Europe. Unlike the US, whose government is pouring money into financing DAC projects, Kenya is still formulating the necessary financial framework to support engineered carbon removal.

Even so, Freimüller says, Octavia has raised $450,000 from investors so far and is on track to generate over $1 million in revenue from the presale of the carbon offsets it will generate by capturing CO₂ in the first quarter of this year.

At the moment, about 10 angel investors and venture capital firms are involved in Octavia, which is in the process of raising $6 million in seed money. And a number of entities—including the Milkywire Climate Transformation Fund, Klimate, and Terraset—have pledged to purchase carbon offsets generated by the project.

Interest in developing and deploying DAC technology is undeniable. Still, some climate technology experts feel that proven, low-tech solutions should be getting more attention.

Josh Knauer, who served as the science and technology adviser for President Barack Obama and is currently an adjunct professor at Carnegie Mellon University and adviser to the New York State Energy Research and Development Authority, says natural, agricultural methods of CO₂ removal are well suited to doing the job.

“Mechanical carbon capture is enormously expensive and still proving its ability to scale,” he says, whereas “good old-fashioned photosynthesis” has been used for millennia for carbon removal. Knauer cofounded a company, ReSeed, that helps small farmers store carbon with regenerative farming techniques.

The Intergovernmental Panel on Climate Change estimates that anywhere from 100 billion to 1 trillion t of CO₂ needs to be removed from the atmosphere to avoid the worst climate impacts. “At scale, photosynthesis is already doing this, overseen by the globe’s 2 billion smallholder regenerative farmers,” Knauer says.

He says 60 million hectares (ha) of farmland could remove the same amount of carbon if they are farmed using regenerative agricultural techniques. And this goal could be reached by enlisting a small fraction of the world’s smallholder farmers, each of whom owns an average of 3 ha of farmland.

In contrast, Knauer argues that when fully commercialized, DAC plants will capture 4,000 t per year of CO₂ at a cost per plant of as much as $500 million. Some 300,000 of these plants will be needed to remove a mere 1.2 billion t of carbon from the atmosphere.

Another challenge for DAC is that other emerging high-tech CO₂ removal approaches may prove to be more effective. Crutchfield points to ocean alkalinity enhancement, a method of adding alkaline minerals like olivine and basalt to the oceans to enhance their ability to absorb CO₂ and convert it into carbonate and bicarbonate salts.

Crutchfield says the technology could dethrone DAC because it is less resource intensive and doesn’t need to compete for land.

Meanwhile, civil society groups in Africa are concerned that advancing geoengineering technologies—be they on land or in the ocean—will negatively affect commitments to large CO₂ emission cuts. During the African Ministerial Conference on the Environment in 2022, more than 30 groups issued a letter stating that such advances offer a technological fix that will allow countries to continue relying on fossil fuels in the face of an ongoing climate emergency.

Freimüller insists that Octavia will never collaborate with the fossil fuel industry, because the goals of the industry are not aligned with climate targets. He cites an investigation by the Guardian newspaper that showed that 94% of carbon credits purchased by the oil and gas industry were fake.

“That could never happen with DAC, because we are closely quantifiable, very easily verifiable, and very durable as a storage mechanism,” Freimüller says.

Geoffrey Kamadi is a freelance journalist based in Kenya.