Editor's Note: Twelve is one of seven private companies Inc. identified that are driving development within seven key pathways to net zero--eliminating one ton of greenhouse gases for every ton emitted.

GETTING TO NET ZERO will require us to harvest carbon, by collecting it where fossil fuels still burn or by pulling it from the air. But what to do with CO2 once we've got it? Ideas range from burying it in rock formations to pumping it into oceans. Or, thought Etosha Cave, she could make stuff. "We're taking CO2 available at any site," she says, "and converting it into useful products."

Cave, who grew up in Houston dreaming of being an astronaut, began working nearly a decade ago on electrochemical processes involving carbon dioxide, as a Stanford PhD student in mechanical engineering. She and her colleague Kendra Kuhl became convinced they'd hit on an idea with world-changing potential: repurposing CO2. Together with Nicholas Flanders, another Stanford alum, they launched Twelve (named for the molecular weight of carbon) in 2015. Flanders, an MBA, became CEO; Kuhl serves as CTO. Cave's title is chief science officer--in part, she reveals, because that was Mr. Spock's role on the U.S.S. Enterprise.

Cave and her colleagues developed a device called a reactor, which stacks a series of plates like pages in a book. Carbon dioxide, water, and electricity get pumped into it. Inside, catalysts innovated by Twelve drive chemical reactions that break the CO2 and water into carbon monoxide, hydrogen, and oxygen. Reactions from another set of catalysts recombine those elements into various organic compounds, with the ultimate aim of turning CO2 into substances other companies can use--and will buy.

Pretty cool technology--unless they actually wanted to build it. At first, local venture capitalists weren't interested in funding a CO2-processing machine from scratch; they were busy chasing hot apps. But Cave was committed, to the extent that she lived in her car for months to save money. Twelve ultimately turned to grants, from public and nonprofit programs that help usher tech from lab to market, to develop its prototype catalyst, a thin black square about the size of a Post-it. The company called it the leaf, in a nod to nature's own carbon-conversion process, photosynthesis. As research progressed, they built bigger reactors that could process more CO2 and produce a wider variety of outputs, depending on the catalysts. By 2019, Twelve had a reactor as big as a steamer trunk, and deals to produce ingredients for Tide laundry detergent; polycarbonates for Pangaia, a U.K. eyewear maker; and raw materials for Mercedes car parts.

With partnerships in place, Twelve went back to the VC well in 2021, and this time reeled in $57 million. Coming next: systems the size of shipping containers, which could sit at any plant burning fossil fuels, absorb its CO2, and reassemble it into material ordered up by Twelve's customers. Net zero, right onsite.