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Feedstock & Technology

Feedstock and technology decide whether a project is viable. This cluster covers sustainable, genuine-waste biomass sourcing and how to match pyrolysis technology — artisanal to industrial — to your feedstock and goals.

Read these before you commit capital to equipment or a feedstock contract.

What makes good feedstock

Good biochar feedstock is dry, reasonably clean, consistently available and genuinely surplus. India generates on the order of 500 million tonnes of crop residue a year with a large surplus fraction, so raw availability is rarely the constraint — collection logistics, seasonality and moisture usually are.

The main Indian candidates are rice husk and straw, wheat straw, cotton stalk, bamboo, coconut shell and sugarcane residues. Each behaves differently: husk carries high silica and leaves more ash, bamboo is hollow and must be split, cotton stalk is woody and yields consistent char. The crop-residue guide covers the belts and the trade-offs, and what biochar is made from summarises them in one table.

Matching technology to feedstock

Technology should follow feedstock and volume, not the other way round. Flame-curtain kilns suit dispersed, farmer-scale material at low capital cost but demand disciplined manual data capture. Batch retorts suit a small business with steady supply. Continuous industrial reactors suit concentrated, consistent biomass at mills or large aggregators, and produce the instrument-grade data buyers increasingly expect.

Capital cost spans several orders of magnitude across those options, and the wrong choice is expensive to unwind. Choosing a pyrolysis technology works through the decision, and our pyrolysis technology advisory does it against a specific feedstock and site.

The integrity test

For carbon purposes one rule overrides the rest: the biomass must be genuinely surplus or waste. Residue that would otherwise be burned in the field qualifies. Roundwood, timber-grade material, or biomass diverted from fodder, fuel or soil cover does not — that moves carbon rather than removing it, and produces credits that will not survive audit.

This is not bureaucratic caution. Feedstock integrity is what protects the price of the credit and the trust of the buyer, and it is the first thing serious diligence examines. Where feedstock is contracted from many smallholders, the fairness and transparency of that arrangement is increasingly scrutinised too.

Frequently asked questions

What biomass qualifies for biochar carbon credits?

Genuinely surplus or waste biomass — typically crop residues that would otherwise be burned or left to rot. Biomass that drives land-use change, roundwood or timber-grade material, and anything diverted from existing uses such as fodder, fuel or soil cover generally does not qualify, because it shifts carbon rather than removing it.

Should I use artisanal kilns or an industrial reactor?

It depends on how concentrated and consistent your biomass is. Dispersed, smallholder-scale residue suits flame-curtain kilns at low capital cost but needs disciplined manual MRV. Concentrated, steady supply at a mill or aggregator justifies a continuous reactor, which produces higher and more consistent quality plus instrument-grade data. Match the technology to the feedstock and volume you can actually secure.

How much biochar do you get from a tonne of biomass?

As an indicative range, a well-run kiln or reactor converts roughly 20–30% of dry biomass weight into biochar, while old-style earth pits yield far less, around 10–15%, at poor quality. Fresh biomass must first be dried — freshly cut material can be 40–55% water — so yields calculated on as-received weight are considerably lower.

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