The $50 million Xprize Carbon Removal grand prize was awarded on Wednesday to Mati Carbon for its innovative yet strikingly simple enhanced rock weathering technology. Funded by the Musk Foundation, this international competition attracted a wide range of advanced carbon removal solutions, from biochar production and waste biomass sequestration to direct air capture and ocean alkalinity enhancement methods.
Mati Carbon’s winning strategy involves finely grinding basalt, a commonly available volcanic rock, to significantly increase its surface area. This processed rock dust is then scattered across farm fields, where it swiftly absorbs atmospheric carbon dioxide and converts it into stable minerals. The simple process not only permanently stores carbon in soils for thousands of years, but also enhances the nutrient profile of the soil itself, contributing micronutrients vital for plant growth.
Basalt is abundant globally, frequently as a waste product generated during aggregate production for the construction industry, making the resource both readily available and economically attractive. Mati Carbon collaborates closely with farmers, spreading the basalt on agricultural lands without cost, supported financially by a combination of grant funding and revenue from carbon credit sales. By the end of this year alone, the startup expects to issue carbon removal credits accounting for around 5,000 to 6,000 metric tons of carbon dioxide removal.
Founder and CEO Shantanu Agarwal said he aims to drive down the price of Mati’s carbon removal credits below $100 per metric ton by the early 2030s, eventually reducing them further—to the $70-$80 per metric ton range. Currently, Mati collects eight soil samples per three acres to verify carbon capture, but improvements in data gathering and modeling will allow fewer samples over time.
Scaling up presents Mati’s most significant opportunity for global impact. According to Agarwal, around 200 million smallholder farmers across roughly 800 to 900 million acres worldwide could utilize the basalt soil amendment. If adopted widely, the technology holds the potential to remove more than a gigaton of carbon from the atmosphere annually, while simultaneously bolstering agricultural productivity and income among some of the world’s poorest populations. Agarwal cites examples from Mati’s projects in Zambia, India, and Tanzania, noting that farmers typically achieve about 25% higher yields in already fertile soils and as much as 50% to 70% increases in previously degraded fields. Moreover, soils treated with basalt dust often retain water better, making crops dramatically more resilient in drought conditions.
Recognizing logistical limitations to rapid expansion, Mati plans to expedite adoption by offering its technology and enterprise software freely to other organizations, under the specific condition that at least half of any profits directly benefit participating farmers.
Already operational in Zambia, Tanzania, and India, Mati Carbon intends to broaden its geographic reach further, planning to begin work in three additional countries within the next year. Ultimately, the company aims to extend its reach across much of the Global South, leveraging the simplicity of its method to create widespread economic and environmental impacts.
Beyond its innovative business model, Mati Carbon is uniquely structured as a public benefit company controlled by the Swahili Initiative, a registered nonprofit. Agarwal explained his vision of utilizing market mechanisms to simultaneously scale carbon removal and significantly raise living standards for millions of smallholder farmers in developing nations. Winning the Xprize, he said, will accelerate the fulfillment of this vision, supporting a mission-driven approach to combating climate change.
