In this installment of the backyard biochar series, I want to reflect a little on scale. In amongst the genuine fun of making and writing about BiocharBiochar is a carbon-rich material created from biomass decomposition in low-oxygen conditions. It has important applications in environmental remediation, soil improvement, agriculture, carbon sequestration, energy storage, and sustainable materials, promoting efficiency and reducing waste in various contexts while addressing climate change challenges. More, you can often forget about the reasons you are doing what you are doing. I had this over the last week. I have been experimenting with my burners over the past few months and I feel it has enriched my knowledge in a way that desk based research couldn’t. However, the actual environmental benefits of these experiments is less apparent, and this prompted me to think more about the role of small scale pyrolysisPyrolysis is a thermochemical process that converts waste biomass into bio-char, bio-oil, and pyro-gas. It offers significant advantages in waste valorization, turning low-value materials into economically valuable resources. Its versatility allows for tailored products based on operational conditions, presenting itself as a cost-effective and efficient More in carbon sequestration and beyond…

A Climate Tool With Promise

Biochar has been heralded by many as a “negative emissions technology” (NET), capable of drawing carbon out of the atmosphere and locking it into stable, soil-enhancing carbon for hundreds to thousands of years. The IPCC has recognised biochar as a viable method for carbon removal, and some projections suggest that globally, biochar could sequester between 0.3 and 2 gigatonnes of CO₂ per year if widely adopted (Lehmann & Joseph, 2015; Woolf et al., 2010).

But these are global figures. Gigatonnes. Industrial scales. What happens when we zoom in – to the scale of a person with a trailer, a few barrels, and a pile of organic waste to make sense of?

The Limits and Logic of Small-Scale

Here’s a rough calculation to illustrate a realistic operation scale for one person. An individual burn might yield somewhere in the region of 10-15 kg of Biochar per burn, using a double barrel system or a Kon-Tiki system (with the double barrel being more convenient in terms of burn regulation). Then, assuming you set a burn 3 times a week, for a year, you will have produced 2,340 kg. As I am typically working with woodier feedstocks, I assume this to have around 80% carbon content – amounting to around 1,800 kg. 

The biomassBiomass is a complex biological organic or non-organic solid product derived from living or recently living organism and available naturally. Various types of wastes such as animal manure, waste paper, sludge and many industrial wastes are also treated as biomass because like natural biomass these More used as feedstockFeedstock refers to the raw organic material used to produce biochar. This can include a wide range of materials, such as wood chips, agricultural residues, and animal manure. More would have been burned, so there is still a positive climate impact to these endeavors. But at 1,800 kg of carbon (= 6,600 kg CO2), with all the assumptions for consistency in place, this is comparable to driving a car for 16,000 miles, 2 round trip flights from New York or half of the energy use of an American home.

So why bother?

Because this work sits at the intersection of climate action and land management. And in that intersection, scale isn’t always about numbers – it’s about networked effort, habit-forming, and integration.

Small-Scale vs. Centralised Solutions

While small-scale systems are accessible, they’re not always efficient. High-tech pyrolysis machines – like continuous flow or gasificationGasification is a high-temperature, thermochemical process that converts carbon-based materials into a gaseous fuel called syngas and solid by-products. It takes place in an oxygen-deficient environment at temperatures typically above 750°C. Unlike combustion, which fully burns material to produce heat and carbon dioxide (CO2​), gasification More reactors – can handle wetter and more complex feedstocks, but they’re often expensive, stationary, and high-maintenance. These systems can cost anywhere from £10,000 to £100,000+ (often looking well beyond the latter), depending on size and capability. That’s not viable for someone managing a waste pile on an acre of woodland, with a hand axe and a lighter.

Could there be a middle ground?

Some models have proposed regional biochar hubs – facilities that collect and process feedstock from local estates, community groups, or conservation bodies. This is already happening in places like Kenya, where decentralised biochar stoves are used in rural households for both cooking and soil improvement. One 2022 study found that a single village-scale unit could sequester up to 50 tonnes of CO₂e annually, while improving food security (Gershenson et al., 2022).

More Than Carbon

I’ve come to believe that the true value of small-scale biochar production isn’t just the carbon numbers – it’s the systems thinking it invites. Every time I gather feedstock, decide which materials to store, coordinate burns, or speak with people, I’m participating in a different kind of economy – one based on stewardship, relationships, and local loops.

Yes, the impact per person is modest. But if we frame biochar less as a silver bullet, and more as a gateway to regenerative practice, its role becomes clearer. It’s an action that links waste to value, land to knowledge, community to care.

We need large-scale solutions for a planetary-scale crisis. But we also need millions of small systems doing the right thing, embedded in place, informed by experience, and adjusted through trial and error.

References

• Lehmann, J., & Joseph, S. (2015). Biochar for Environmental Management: Science, Technology and Implementation (2nd ed.). Routledge.
• Woolf, D., Amonette, J. E., Street-Perrott, F. A., Lehmann, J., & Joseph, S. (2010). Sustainable biochar to mitigate global climate change. Nature Communications, 1(56), 1–9.
• Forestry Commission UK (2020). Managing Woodlands in England: Opportunities for Productive Use of Low-Value Biomass.
• Gershenson, D., Mendum, R., & Nartey, E. (2022). Village-scale biochar systems for sustainable agriculture and carbon mitigation: Field data from East Africa. Journal of Cleaner Production, 360, 132072.