Companies like Microsoft, Shopify, and Stripe pay Charm $600 for every ton of carbon it puts underground, either to offset their own emissions or to help build up an industry that will need to play a critical part in tempering climate change, by pulling huge amounts of greenhouse gas out of the air and storing it away.

The San Francisco startup has been sequestering carbon this way for the past two years. Late last year, the company announced that the process has safely locked up nearly the equivalent of 5,500 tons of CO2 so far, claiming that’s the largest amount of long-term carbon removal delivered to date. But it’s a tiny sliver of the billions of tons per year that climate scientists warn the world may need to suck up in the coming decades to pull the warming planet back into a safer zone. And there are plenty of questions and concerns about how reliable, scalable, and economical this approach will prove to be.

The company has edged ahead of others mainly because it’s taking a simple approach. It leans on agricultural crops to capture the carbon and uses existing formations for storage. And Charm doesn’t have to construct big projects, sidestepping some of the development, permitting, and capital challenges that startups like Climeworks or Carbon Engineering have encountered as they try to build carbon-sucking factories.

But an early lead in a field that scarcely exists doesn’t necessarily say much about how the company will fare as the market develops. Notably, the next generation of direct-air-capture plants coming online are meant to remove a million tons a year, 180 times more than Charm has achieved so far.

The company will also face some obvious challenges as it scales, including the rising costs of shipping waste between fields and wells, competing demands for the agricultural byproducts it relies on, and questions around how much net carbon its approach ultimately removes.

In addition, the company will face the same risk as other young companies in carbon removal and storage: they’re gambling that large corporations will be willing to continue footing the high bill for cleaning up the atmosphere, and that governments will enact the necessary policies to build up the costly sector.

Corn stalks to carbon credits

Charm’s CEO, Peter Reinhardt, 32, previously led Segment, a customer data software company that Twilioacquired in 2020 for $3.2 billion. He started looking into carbon removal as a way of offsetting Segment’s emissions, initially exploring possibilities like funding rainforest protection.

In 2018, Reinhardt and three others cofounded Charm (a mashup of “char” and “farm”) to build a business around what they saw as a more promising approach. The initial plan was to gasify biomass, a similar process to pyrolysis but done at higher temperatures, to produce biochar and hydrogen. They expected the latter to be the real moneymaker.

But the company found that picking up the biomass and transporting it to a centralized gasification facility was far too expensive, becausebiomass is “too fluffy.” It’s bulky, heavy, and unwieldy, increasing the cost of handling and moving it—a painful lesson that biofuels companies learned more than a decade ago.

In 2020, Charm’s chief scientist, cofounder Shaun Meehan, had a bright idea: if the company was willing to do what Reinhardtdescribes as “half-assed gasification,” yielding bio-oil instead of hydrogen, the equipment could fit into the back of a semi-trailer. Then the company could pull right up to farms and carry out the process at the edge of the fields.

Now Charm, which has about 30 employees, pays farmers to allow it to pick up unwanted plant materials left after harvesting. It’s also looking at carrying out the same process with trees and plants removed from forests—say, for fire prevention or in the aftermath of droughts. Separately, the company has begun to explore whether it can use the resulting bio-oil to clean up steel and iron production, the dirtiest industrial sector (see related story).

The business model would make no sense in any other time (and perhaps it doesn’t in this one). But a growing number of companies are willing to pay the high cost of carbon removal and storage as a way of balancing out their own emissions, to help support the emerging market, or as a form of climate philanthropy. So far, around 40 organizations have purchased tons of removal from the company….”