NetZero started as a family story over three generations. Guy Reinaud, the grand-father, was running Pro-Natura International, an NGO that pioneered biochar production and use in the 2000s, with a strong focus on developing countries. In 2020, Axel and Olivier, father and son, took advantage of the Covid-19 lockdown to build on Guy's ideas and developed a model capable of bringing biochar at scale, using carbon credits as a key lever and the tropics a the target geography. NetZero was born!

When the project was still at the idea stage, three other key people joined Axel and Olivier as co-founders: French climatologist Prof. Jean Jouzel, former vice-chair of the IPCC; Cameroonian agro-industrialist Aimé Njiakin, who provided the location to build NetZero's demonstration plant; and Brazilian engineer Pedro de Figueiredo, a former senior manager at Vallourec with deep expertise in industrial pyrolysis processes.

The company was officially incorporated in January 2021 in France. Very soon after, a group of 23 pioneer business angels provided the necessary seed funding to launch NetZero's activities.

Biochar can be produced from a wide range of biomasses. However, there are three main types of considerations when choosing the feedstock:

• Sustainability requirements – the biomass needs to be residues, not puropose-grown feedstock, and needs to be deforestation-free.
• Physio-chemical parameters – the dryer, more ligneous, and more homogeneous the biomass, the better, with ideally relatively small granulometry.
• Logistical aspects – the more centralised the biomass is, the easier and cheaper it is to used it for biochar production.

At NetZero, we have chosen to focus on residues from tropical agriculture. They currently have little valorisations schemes, are very abundant, and are a way to make sure they do not come from deforestation.

During biochar's production process (pyrolysis), significant amounts of flammable gases (syngas) are generated. As they come from the thermal degradation of renewable biomass (crop residues), these gases are renewable energy. NetZero's production process recovers the syngas and uses them for two puroposes:

1. Self-sustain the pyrolysis process, which requires temperatures of 500–600°C. Only when starting a production run does the pyrolysis process require an initial energy input.
2. Use the extra syngas to co-generate renewable energy, both as electricity and heat, that can be made available to local users (companies, mini-grids, national grid, etc.).

Carbon credits have long been rightfully accused of greenwashing. They were cheap, poorly certified, focused mostly on emission avoidance (i.e., avoiding putting more carbon in the atmosphere, as opposed to removing carbon from the atmosphere), and with no permanence guarantee. Companies were buying these low-quality credits to claim they had offsetted their emissions, with little to no actual effect.

NetZero's carbon credits are very different and therefore do not suffer from the abovementionned issues:

• They are very expensive for companies to buy (3-digit price per credit in euros). These high prices ensure that only unavoidable, very hard-to-abate emissions are offsetted by companies using carbon credits, and that the vast majority of climate efforts are focused on reducing emissions at the source. To be noted that, incidentally, such prices also allow to subside the agricultural use of biochar, making the product affordable for farmers.
• They only account for carbon removal, meaning that quantification of their climate benefit is much more reliable that theoretical calculations of avoided emissions. In the case of carbon removal, the carbon is literally weighed at the production facility.
• The methodology and standard used to certify them are extremely stringent and exhaustive, accounting for all value-chain emissions of the project and asking for full traceability, from biomass sourcing to biochar's final use.

By convention, carbon capture refers to filtering greenhouse gases at a source point (e.g., the chimney of an industrial facility), where flue gases are concentrated. This filtering technique can be combined with a subsequent step of underground storage of the gases; the process is then referred to as carbon capture and stored (CCS). CCS prevents adding more carbon to the atmosphere, and is therefore an emission-avoidance solution.

Carbon dioxide removal (CDR) on the other hand targets carbon already released and diluted in the atmosphere. CDR methods allow to take this carbon out and sequester it so that it no longer creates greenhouse effect. This approach is much more complex than CCS as CO₂ makes up only 0.04% of ambient air.

Biochar is one of the most energy-efficient CDR solutions available, as it does not require technology to take the carbon out of the atmosphere; instead, plants do it naturally through photosynthesis. Only the sequestration part (extraction and stabilisation of the carbon from the biomass) requires human intervention (pyrolysis technology + biochar burial) to make sure the carbon will not go back to the atmosphere.

To be noted that, in order to reach net-zero emissions by mid-century, it will be necessary to combine all solutions, so no working technology should be put aside.

As for every practice related to agronomy, biochar's effects can vary depending on soil type, crop type, agricultural techniques, weather, and more.

However, scientific studies unanimously conclude that biochar has significant positive effects when adequately applied in tropical soils. Compared to baseline agricultural practices, biochar raises yields by a double-digit order of magnitude when applied in the range of 1 kg/m².

These benefits are mostly explained by the following three physio-chemical characteristics of biochar:

1. Its high porosity (specific surface area) allows to greatly improve soil's water-holding capacity, making crops much less subject to hydric stress and overall improving farming resilience.
2. Its negatively-charged surface (cationic exchange capacity) allows to retain nutrients at plant root level, allowing the plant to grow more. This also means that nutrient leaching is greatly reduced, which can allow to reduce the use of fertilisers without compromising yields.
3. Its high (alkaline) pH allows to rebalance soil acidity – a key issues with virtually all tropical soils. pH has a direct incidence in nutrient assimilation by plants: by making soils less acidic, biochar maximises plants' feeding and also allows to build on organic matter in soil, which in turn provides more nutrients for plants.

Biochar should preferably be used after an agronomic diagnosis assessing soil quality and baseline farming practices, in order to determine the optimal dosis and application method. However, here are some general guidelines:

• Biochar should always be buried in the soil, not just spread over. It behaves as a sponge that retains water and nutrients, so it should be applied at plant root level.
• Its application should be homogeneous accross the treated zone, meaning it is necessary to mix soil and biochar together, not just cover the biochar with soil.
• Biochar works best when combined with fertilisers, whether natural or synthetic.
• Biochar is most effective on seedlings and young plants. For trees, the ideal scenario is to apply biochar during nursery and at the transplanting stage.
• Unlike conventional fertilisers, biochar is to be applied only once. This is because biochar is not made of nutrients but is rather a physical compound that remains in the soil and becomes part of its structure.

Biochar has been extensively studied by scientists since the 1990s, both for its agronomic benefits and its climate impact. Over 15,000 publications have explored biochar's properties, use, impact, life cycle analysis, and more.

Some of the most recent, comprehensive, and best-regarded studies include Joseph et al. (2021) on agronomic aspects and Lehmann et al. (2021) on climate aspects.

NetZero's model differs from other industrial biochar producers in many aspects:

• Geography – We are the first biochar pure player to operate at industrial scale in the tropics. Virtually all other industrial producers are based in Europe, North America, and China. We believe our positioning is strategic given the very large amounts of unused residual biomass available in the tropics.
• Feedstock – We only use residual biomass from agriculture as a feedstock, whereas virtually all other producers use forest residues. Our choice is driven by our willingness to make sure we do not contribute to tropical deforestation.
• Circularity – We operate an extremely local and circular model whereby our feedstock suppliers are also our biochar clients, all within a 30km radius from our production facility. This model differs from most biochar producers, who source the biomass somewhere and sell their biochar somewhere else, with the product usually having to travel significant distances. Our circular model allows to ensure maximum adhesion of farmers, to guarantee long-term biomass supply, and to ensure full traceability of our biochar use.
• Integration – We operate an end-to-end model, from sourcing the biomass to distributing the biochar, from producing to conducting agronomic trials, from R&D to certification. To our knowledge, no other biochar player is fully integrated.
• Ambition – NetZero's raison d'être is scale. We are not interested in doing just a few projects, but rather thousands of them. Our model (i.e., all the above-mentionned points) was built for that, and we are working relentlessly to converge to a franchise model that will allows to maximise scale and impact.

NetZero's model was built for the tropics since the beginning. This geography gives access to massive amounts of unused crop residues, maximise the agronomic benefits of biochar, and maximises social co-benefits. It is therefore an ideal geography to scale biochar. Some tangent areas such as Sahel and some parts of the Southern Mediterranean could also work, but it would be a case-by-case approach and such locations would anyway not represent a significant potential.