If you run a palm oil mill, a cashew processing facility, or a timber yard, you probably already know what biochar is not. It is not compost. It is not charcoal for cooking. It is not a fertilizer in the traditional sense.
What it is — and why it matters for your operation — is worth understanding clearly.
The basic answer
Biochar is a stable, carbon-rich solid made by heating plant waste in a low-oxygen environment. The technical name for that process is pyrolysis.
Here is the key difference from burning. When you burn palm kernel shells or sawdust in open air, the carbon inside reacts with oxygen and escapes as CO2 gas. The carbon is gone. When you run that same material through a pyrolyzer — a sealed, controlled heating system — without oxygen, the carbon has nowhere to go. It stays locked inside the solid material that comes out. That material is biochar.
Think of it like this: burning converts solid carbon into invisible gas. Pyrolysis converts solid carbon into a different solid, one that is stable for hundreds of years.
Why palm kernel shells and sawdust are among the best feedstocks
Not all agricultural waste makes equally good biochar. The quality of the output depends on what goes in.
Palm kernel shells score very well. They have around 50% carbon content, 15% moisture, and are concentrated at mill sites in large volumes — typically 300 tonnes per month or more at a commercial mill. Cashew nut shells score even higher: 55% carbon content, only 10% moisture, generating 2.31 tonnes of CO2 equivalent per tonne of biochar produced.
Sawdust works well too, though moisture management matters more since it arrives wetter from active mills. Dried sawdust or mill residue from timber operations performs comparably to PKS.
Feedstocks that do not work well are those with very high moisture content — like fresh fruit bunch residue or mango waste — because drying costs erode the economics.
What the machine looks like in practice
A small pyrolyzer unit fits in a space of roughly 10 metres by 10 metres. It runs on 3-phase power, requires around 5 kilowatts, and sits near the existing processing line. Waste goes in one end. Black, granular biochar comes out the other.
The process runs continuously. There is no open flame, no significant smoke, and no disruption to the factory core operation. The biochar that comes out is dry, odourless, and stable enough to bag and transport.
What the biochar does once it leaves the factory
The biochar produced from your palm kernel shells or sawdust has two commercial destinations.
The first is as a soil amendment. Applied to farmland, biochar improves soil structure, increases water retention, and boosts nutrient availability. Field trials in Cross River State and Kaduna showed yield improvements of 20 to 46% in maize, cassava, and waterleaf when biochar was applied alongside standard fertilizer. In one trial, combining 3.5kg of biochar with 0.25kg of NPK fertilizer produced a 46% yield improvement — compared to just 5% from fertilizer alone.
The second destination is the international carbon credit market. Because biochar locks carbon into soil permanently, it qualifies as a verified carbon removal. Buyers in the US and EU pay $140 to $200 per tonne of CO2 equivalent removed.
For a processor, this means the palm kernel shells or sawdust currently being burned or dumped can generate new annual revenue — without touching the core business.