Frequently Asked Questions

Biochar is a stable, carbon-rich material made by heating organic matter — in our case rice husk and rice straw — at high temperature with little or no oxygen, a process called pyrolysis. Instead of the plant material rotting or being burned (which releases its carbon back to the atmosphere), the carbon is locked into a solid, charcoal-like form that resists breaking down for centuries.

Rice plants pull CO₂ from the air as they grow. Normally that carbon returns to the atmosphere within months as the husk and straw decompose or are burned. Pyrolysis interrupts that cycle: it converts roughly half of the biomass carbon into biochar that is highly resistant to decay. Certified under the Puro.earth methodology, this carbon is recognised as durably stored for 200 or more years (CORC200+).

They are related but not the same. Both are made by pyrolysis, but charcoal is produced as a fuel to be burned, which releases its carbon again. Biochar is produced specifically to be used as a durable material — for soil improvement and carbon storage — so its carbon stays locked away rather than being released.

A CORC is a CO₂ Removal Certificate issued by Puro.earth. Each CORC represents one tonne of CO₂ that has been durably removed from the atmosphere and independently verified. When an organisation buys and retires a CORC, it is funding real, measurable carbon removal — not an avoided emission.

The Mina project follows the Puro.earth Biochar Methodology and is monitored through Carbonfuture's digital measurement, reporting and verification (MRV) system, which tracks data from feedstock through pyrolysis to the finished biochar. Independent third-party auditing confirms the volumes before certificates are issued, so every credit is traceable and audited.

Producing biochar from rice residue is close to break-even on its own; the carbon-removal revenue is what makes the project viable. Without it, the rice husk and straw would continue to be burned or left to rot, returning their carbon to the atmosphere. The carbon finance is the enabler, which is what ‘additionality’ means.

Durability is the defining strength of biochar. Because the carbon is in a stable mineralised form, the reversal risk is very low compared with nature-based approaches such as forestry. The Puro.earth standard the project uses certifies storage of 200+ years, and permanence is assessed as part of the verification.

Every CORC is uniquely serialised and recorded on the Puro.earth registry. Once a certificate is retired on behalf of a buyer it cannot be sold or claimed again, which prevents the same tonne of removal being counted twice.

Compared with forestry, biochar offers much greater permanence and far lower reversal risk (trees can burn, be cut, or die). Compared with engineered approaches such as direct air capture, biochar is available and affordable today and delivers strong agricultural and social co-benefits. It is one of the most-delivered forms of durable carbon removal currently on the market.

Applied to fields, biochar improves soil health — helping the soil hold water and nutrients, reducing the need for fertiliser, and supporting stronger, more resilient rice yields. Alongside the environmental gains, the project creates rural jobs and new income for farming families in Iloilo.

Across Iloilo, large volumes of rice husk and straw are burned in the open or left to decompose, which pollutes the air and releases greenhouse gases including methane. Diverting this residue into biochar turns a disposal problem into climate benefit, cleaner air, and value for farmers.

We work with carbon-credit buyers, ESG partners and investors. To discuss purchasing durable carbon removals or an investment or partnership, please contact us or see the Invest & Partner page.