It’s Tuesday, and today we’re looking at Octavia, a Kenyan Direct Air Capture (DAC) startup. Founded by Martin Freimüller and Duncan Kariuki, the company has raised $4.6 million from investors including Lateral Frontier, E4E Africa, and Catalyst Fund.

Every year around 40 billion tonnes of CO2 is released into the atmosphere, most of it from burning fossil fuels. That extra CO2 is long-lived: it stays in the atmosphere for 300-1,000 years. So if we went net-zero tomorrow, that wouldn’t remove all the CO2 accumulated has been added in the past hundreds of years.

That’s why carbon capture exists. It allows us to remove the CO2 that is already in the atmosphere. There are two basic ways to capture carbon:

CCS is used for mitigation (i.e. not letting new carbon enter the atmosphere), CDR is used for removal (i.e. removing existing carbon). CCS is much cheaper (PSC ranges $15-120/t depending where the capture happens, while CDR can beup to $1,000/t). The problem is, of course, that most emissions are generated by millions of small energy-dependent units, like cars or ACs.

So today we’ll talk about removing carbon from the atmosphere, and specifically focus on DAC — machines capturing CO₂ from ambient air anywhere you can supply low-carbon heat and electricity. The tech is in its nascent stage of development; however, proponents of this technology are betting that it can grow from basically zero today to capturing over 60 million tonnes of CO₂ a year — in five years.

Although there are temperature and overall climate considerations, the most important factors when choosing where to locate DAC machines are supplying those machines with energy to function and finding a place to store the captured CO₂.

And that’s how we come to Kenya.

Let’s start with energy. Ninety percent of Kenya’s electricity comes from renewables — and specifically, geothermal — which today supplies 47% of the country’s power. Of the 3 GW installed capacity, only 50–60% is used due to limited industrial demand. Meaning that a lot of clean, cheap electricity isn’t being used. That excess capacity can now power the fans and pumps inside DAC machines.

But electricity isn’t enough. The DAC process also requires low-temperature heat (about 85–120°C) to regenerate the sorbent — i.e., to release the CO₂ it has captured so the material can be reused. Geothermal wells happen to produce hot brine in exactly this temperature range. That heat can be transferred directly to DAC units without burning any extra fuel. And because this heat is essentially a by-product that would otherwise be wasted, it’s both inexpensive and virtually carbon-free.

So reason #1 why Kenya is special for DAC — geothermal energy with the right properties: renewable, clean, already in place, and producing both electricity and usable heat.

Once CO₂ is removed from the air, it needs to be stored permanently. You could theoretically use pressurized tanks, but that’s expensive. Practical options include depleted oil and gas fields or porous rock formations. Kenya has few depleted reservoirs — but it does have the Rift Valley, underlain by thick basalt. Basalt is a volcanic rock that reacts with injected CO₂ to form solid carbonate minerals within about two years, locking away carbon for millennia. According to one estimate, Kenya has enough geological capacity to store all of humanity’s cumulative CO₂ emissions.

So reason #2 why Kenya is special for DAC — geology that permanently stores CO₂ safely, naturally, and at massive scale.

Octavia’s in the business of building DAC machines, leveraging Kenya’s unique geography and geology.

A DAC machine works in two phases:

Octavia’s unique feature is using a patent-pending sorbent, allowing the company to reuse excess geothermal heat, which would cater to 80% of the company’s energy needs.

Next part is storage, that’s currently handled by Octavia’s partner, Cella. The captured CO₂ is injected deep underground at high pressure into volcanic rock formations. These rocks, rich in calcium and magnesium, react with the CO₂ to form calcium carbonate — or limestone — permanently locking the carbon away.

Octavia’s first project, named Hummingbird, will remove up to 1,000 tons of CO₂ per year at full capacity.

The DAC industry is still small. As of 2024, only 27 DAC plants were operating globally, capturing a total of just 10,000 tons of CO₂ per year. Another 130 facilities are planned or in development — but how many of those will materialize is uncertain. Notably, 100 of the 130 are led by a single company, 1PointFive. A lot is riding on just one player.

Why is DAC still so rare? Mainly: cost and energy requirements.

Removing 1 tonne of CO₂ via DAC currently costs between $600 and $1,000. That’s just the price tag. The energy side is a separate — but equally daunting — hurdle. Each tonne removed requires roughly 0.5–1 MWh of electricity and 2–3.5 MWh of heat. That’s up to 4.5 MWh per tonne.

These numbers didn’t mean much to me, so I went on Amazon, found a popular refrigerator, and it turns out you could run it for 14 years on that amount of energy. That’s a lot.

This is where Octavia’s location choice becomes a core part of its strategy.

By operating in Kenya, the company addresses both major pain points:

Energy — it’s a technical challenge, yes, but from a business angle it’s relatively straightforward. Using geothermal heat to meet 80% of energy needs means:

Cost — beyond energy, Octavia keeps costs low through design. The company avoids expensive or overly complex components. All manufacturing takes place in Kenya, and nearly the entire team is local — keeping production, logistics, and labor costs down.

That’s why CEO Martin Freimüller believes that reducing costs to $100 per tonne is a realistic goal.

Most DAC companies monetize by selling carbon credits — and Octavia is no exception. Between 2022 and 2024, it secured $1.1 million in carbon credit prepayments. For buyers, the current price to remove 1 tonne of CO₂ is $1,000.

Estimates for how much CO₂ humanity must pull back out of the air vary wildly—sometimes by a factor of ten. Let’s use the low end: about 5 billion t/year of removals by mid-century, a figure Octavia itself quotes here.

Hummingbird, Octavia’s first plant, will capture 1,000 t/year. At that rate we would need 5 million Hummingbird-size plants to hit 5 Gt. That would never happen — later-generation plants will almost certainly grow larger, but the simple math illustrates the giant gap between today’s capacity and the size of the problem. Even Octavia’s lofty ambitions can’t close it alone.

That scale mismatch risks scaring away future investors. If it looks impossible to make a dent, the worry will be: why pour in capital at all? No capital → no scaling → no cost decline. A vicious cycle.

But maybe a bigger problem — cheaper, “natural” options such as mass tree-planting. Sure, forests take decades to mature, can burn, and sometimes displace ecosystems. But pumping CO₂ into volcanic rock is not impact-free either (we simply don’t have long-run field data). And it’s not like DAC tech is the easiest to scale also. Until DAC prices fall orders of magnitude, backlash that “we should just plant trees” will keep returning.

Could DAC carve out a niche for buyers who need precise, auditable carbon removal data? Possibly. But for now, the niche is tiny.

I don’t understand the tech nearly well enough to predict a 100- or 1,000-fold efficiency breakthrough. What matters for the bull case is cost: if Octavia can get removal down to about $100 per tonne, it will undercut most rivals.

If Octavia scales in Kenya, demonstrates its value to the local economy, and brings costs down, it could become the exclusive DAC operator in the country. If that happens — and no other country offers the same combination of cheap energy, affordable labor, and suitable geology — it could become the go-to player in the DAC space, with Octavia securing its cornered resource: in this case, an entire country.

The continued support from governments worldwide may also provide a growth boost. Government-backed funding would serve as an acknowledgment of this technology as a legitimate solution to a global problem, making it more attractive for businesses to include DAC in their net-zero plans moving forward.

It’s so interesting that there are still industries that are extremely small but solving global problems for clients all over the world. You’d think that every industry with those two characteristics would already have its incumbents — but no. Humanity still finds new ways to solve old problems.