Google announced today that it will purchase 100,000 tons of carbon removal from a biochar project in Gujarat, India. The deal, seven months in the making, is the largest biochar offtake to date.
Biochar is a carbon-rich material made from heating organic matter in the absence of oxygen. It can trap carbon for centuries. And the resulting charcoal-like material makes a high-quality soil amendment, boosting nutrient content and water retention.
Google’s carbon removal purchases will help the company meet its own net zero target. What’s more, its buying strategy prioritizes projects that lay the groundwork for planetary net zero. Biochar is a promising carbon removal pathway owing to its measurable climate impact, opportunity for scale, low cost, and additional soil health benefits.
“Our program is all about removing barriers to certainty of impact and scale of impact,” said Randy Spock, carbon credits and removals lead at Google. “Biochar is promising on both of those fronts.”
From an invasive weed to a carbon removal machine
Project developer Varaha will produce the biochar from an invasive species of mesquite that has aggressively advanced into India’s grasslands, sucking up soil nutrients and moisture and crowding out the native ecosystem. The damage has depressed milk production from cattle grazing, damaging local livelihoods.
The problem has become so acute that local governments across the country fund eradication programs to remove the shrub. But there hasn’t been a clear plan for what to do with the huge brush piles once they’ve been pulled out of the ground. Typically the piles are burned or left to rot, releasing the plant’s carbon content into the atmosphere, said Madhur Jain, CEO of Varaha, an India-based regenerative agriculture startup founded in 2022 to improve soil health.
The new biochar deal will enable Varaha to set up at least six industrial biochar reactors, each with the capacity to lock away about 30 tons of CO2 per day. Varaha will feed the weeds to the reactors to heat and convert into biochar, delivering the contracted carbon credits to Google over the coming five years. The resulting biochar will be used to aid in the region’s grassland restoration.
How the deal came together
The agreement represents a unique collaboration between a South Asian agriculture startup and the world’s most prominent tech corporation.
At several points in the discussions, Google asked Varaha for information it didn’t yet have. Those moments became opportunities for transparency and built trust between the regenerative agriculture startup and tech leader headquartered on the other side of the world:
“Being open that we don’t have XYZ, rather than making this up, really worked in our favor because it helped build trust,” said Jain. “They got a whiff that they are working with the right people even though we are far away.”
Varaha had experience working with small farms to produce biochar using artisanal methods. Those existing relationships helped Varaha showcase its readiness to work with local communities. But without experience running an industrial biochar facility, the company had to prove it was ready to deliver carbon removals at scale.
The big unlock came in October, 2024, when Varaha successfully listed nearly 1,750 verified industrial biochar carbon credits on the Puro.earth registry from a smaller facility it operates. “In 5 weeks we were able to sign the contract [with Google],” said Jain.
Another important due diligence milestone came when Varaha submitted biochar samples for evaluation at a third-party lab, testing for heavy metals, suitability as a soil amendment, and permanence of carbon storage. “The lab told us it was the best biochar in the world in terms of permanence,” said Jain.
For Google’s team, that transparency also meant being realistic about the project scope and timeline. “Making sure there isn’t an overly rosy picture by either party about what is possible when, and a truly honest conversation about what is the best way to build this stuff with maximum credibility,” is a key consideration in this and Google’s other carbon removal purchases, according to Spock.
Biochar’s potential for scale
Biochar could capture and store as much as 2.6 billion tonnes of CO2 per year with existing technology and at low cost, according to the Intergovernmental Panel on Climate Change. Of that, 1.1 billion tonnes per year could come at a cost of less than $100 per ton.
“I think India will be the largest biochar-based carbon sequestration player in the world,” said Jain. “We have skilled labor, reactors, and biomass in ample capacity.”
The deal serves as a model of a large carbon purchase designed to catalyze climate benefits that last well beyond the end of the contract. Many companies have shied away from incorporating carbon credits into their climate strategies due to concerns over reputational risks should projects underdeliver.
“The antidote to any reputational risk to any buyer is honesty,” said Spock. “I would encourage other buyers that getting involved can be easier than you think, and being honest can be the best policy for yourself and helping grow the field.”