Sustaera, a start-up that sucks planet-warming carbon dioxide out of the air, raised $10 million from a Series A funding round led by climate funds backed by Bill Gates and billionaire investor Jeremy Grantham.
The company, based in North Carolina, uses a cheap and easily available alkali-based material to absorb CO2. Unlike other carbon-capture businesses, its process does not require heat from fossil fuel sources and can run entirely on renewable electricity. Payments system provider Stripe has signed on as its first customer.
Sustaera is trying to solve one of the biggest hurdles in carbon removal: scaling the technology, which remains expensive and challenging to use. The company’s machine is built in a modular fashion, with single units that can be put together “like Lego blocks”, chief executive Shantanu Agarwal said.
It also “leverages existing systems, existing supply chains, existing manufacturing, rather than creating everything from scratch”, Mr Agarwal said. “That’s very important when you’re trying to tackle something like carbon capture which needs to be done at scale.”
In September, the world’s largest carbon-removal plant, which can remove 4,000 tonnes of CO2 a year, started operating in Iceland.
People can pay Climeworks up to $1,200 per tonne of CO2 for offsets from the Iceland facility. Bulk purchases, such as those made by Mr Gates himself, can cost closer to $600 per tonne.
Stripe has signed up to purchase carbon captured by Sustaera’s first machine, set to be completed in 2023 and remove 10 tonnes of CO2 a day, at $700 a tonne. The firm is looking at sites for its machines in Florida, Texas, California, Wyoming, North Dakota, as well as Spain and Oman.
It was the use of existing supply chains and the ease of scalability that attracted Mr Gates’s Breakthrough Energy Ventures, said Carmichael Roberts, who co-leads the fund’s investment committee.
“This is the type of solution we look for — designed to scale quickly and provide a viable economic negative emission pathway,” he said in a statement.
Sustaera plans to build a unit in 2027 that can remove one million tonnes a year, requiring about 100 acres of land. The company should then be able to aim for a capture price of $78 per tonne, Mr Agarwal said.