Biochar Case Study: Tierra Prieta
Our Case Studies series demonstrates real biochar projects around the world from IBI members who are making an impact.
Every day, plants around the world are quietly working in our favor.
During photosynthesis, they absorb carbon dioxide (CO2) from the atmosphere and store it in their biomass—roots, trunks, leaves, fruits, and shells. It is one of nature’s most powerful climate change solutions, happening continuously and at a global scale.
But there is a problem.
The carbon captured by plants does not stay locked away forever. When plants are burned, that carbon is released almost instantly back into the atmosphere. When they decompose, the same thing happens—just more slowly. Either way, the result is the same: the carbon returns.
This creates a cycle. A loop. Carbon is absorbed, stored briefly, and then released back into the atmosphere. Over and over again.
And it’s not just about capturing CO2; plants already do that every single day. The real problem is storing it. We are not keeping the carbon out of the atmosphere long enough to make a lasting difference. There is no long-term solution in a system where carbon is constantly re-released.
In the northern state of Coahuila, a different idea began to take shape in 2023, from an unlikely source: the pecan tree.
Tierra Prieta and the Solution to Pecan Waste
Pecan trees, widely cultivated in this region, absorb CO2 as they grow, storing carbon in every part of their structure—including their nuts and shells. The nuts are harvested, sold, and consumed. But the shells, which represent a significant portion of the biomass, are often treated as waste.
In many cases, these shells are burned or left to decompose. And when that happens, the carbon they contain returns to the atmosphere—again.
But what if it didn’t have to?
This question led Andrés Chapa to take action. Seeing both a problem and an opportunity, he founded Tierra Prieta, an initiative driven by a simple but powerful idea: instead of allowing agricultural waste to release its carbon back into the air, what if that carbon could be stabilized and stored? What if, instead of cycling carbon, we could keep it?
This question became the foundation of Tierra Prieta’s work.
This case study provides insight into the company’s biochar production facility, initiated in 2023, which converts pecan shell waste from the local pecan industry into durable biochar through pyrolysis.
The project achieves verified carbon dioxide removal (CDR), generating CORCs (CO2 Removal Certificates) through the Puro.earth registry under the Puro Standard Biochar Carbon Removal methodology. The physical biochar is exported to the U.S. market, for both agricultural and building material applications, while carbon credits are sold exclusively through Carbon Direct. The facility currently operates one pyrolyzer producing approximately 2,000 CORCs per year, with expansion plans to double capacity by Q3 2026.
The Biochar: Production Process and Project Specs
Pyrolysis involves heating organic material (such as pecan shells) at high temperatures, in the absence of oxygen. At Tierra Prieta, their process utilizes temperatures between 550–700°C, with heating time between 1 to 4 hours.
Through pyrolysis, the nature of carbon itself is changed. It moves from a short-term biological cycle into a long-term storage system. Instead of returning to the atmosphere within months or years, it can remain locked away in biochar for centuries.
| Pyrolysis Temperature | 550–700C |
| Heating Rate | Slow (<10°C/min) |
| Residence Time | 1–4 hours |
| Final Biochar Particle Size | Micronized sizing, through 1cm flakes |
| Feedstock to Product Ratio | 3 |
| H/Corg Ratio | 0.21 |
| Approx. Production Cost | Under $0.50/kg |
| Approx Market Price | Under $1.00/kg |
| Application Areas | Agriculture, Building Materials |
Key Success and Challenge Factors
Tierra Prieta operates in a space where, as they describe it, “there is no playbook.” There is no consistent, established roadmap for biochar production or scaling carbon removal.. So they discovered that the hardest part is not starting something, but operating and solving multiple challenges at once: developing reliable pyrolysis technology, working with variable feedstock (since agricultural residues differ in composition, moisture, and quality), and building and scaling a new model in an emerging market.
“A biochar business cannot succeed if you solve only one problem. Feedstock and pyrolyzer design are the most important decisions, and you should never believe any manufacturer. The standard startup playbook does not apply. “
– Andrés Chapa, Tierra Prieta
Each of these challenges requires constant experimentation, adaptation, and resilience. This is not a linear process.
What Tierra Prieta does goes beyond simply storing carbon. By transforming agricultural waste into biochar, they create a product that delivers tangible benefits to the land. When applied to soil, biochar improves its physical and chemical properties. It enhances water retention, helping soils hold moisture for longer periods.
It also helps retain nutrients near plant roots, reducing the need for synthetic fertilizers and improving crop yields. In this way, Tierra Prieta is not only addressing climate change but also supporting agricultural resilience and productivity.
A key part of Tierra Prieta’s ongoing work is developing a reusable, durable, and flexible system. This system is designed to efficiently process various types of biomass while adapting to the realities of agricultural production.
At the same time, durability ensures that the technology can operate consistently over long periods, reducing costs and increasing impact.
“Focus on quality and being realistic as to what we can output, plus being as lean as possible. There is no playbook, we knew we were getting into uncharted water and are constantly reassessing our own work. We succeeded when we found a way to produce very high quality biochar, and leaned into it. “
– Andrés Chapa, Tierra Prieta
Tierra Prieta’s process is also designed with safety and environmental responsibility in mind.
Their operations follow strict internal protocols, including standard operating procedures (SOPs) tailored to their specific processes. By maintaining tight control over the pyrolysis process, they aim to avoid contamination and minimize negative environmental impacts.
Tierra Prieta offers a different path—one where agricultural waste is no longer seen as disposable, but as an opportunity. One where carbon is not simply cycled, but stored. By processing residues like pecan shells through controlled pyrolysis, they transform a temporary form of carbon into a stable, enduring form.
A long-term answer to a long-term problem.
Tierra Prieta’s work highlights a broader reality for the biochar industry: the opportunity is clear, but the pathway is not standardized. Each project must navigate its own constraints—feedstock, technology, and market—often without precedent.
What emerges is not a single model, but a set of evolving practices. The project demonstrates a scalable, commercially viable model for biochar-based carbon removal using agricultural waste feedstock in Latin America, contributing to both climate change mitigation and local economic development in the Coahuila region.
And in that sense, Tierra Prieta is producing biochar while helping define how this industry learns to operate.