The small unit CARBO+ carbonises biomass such as green cuttings, wood or branches and converts it into high-quality plant charcoal. The charcoal serves as an aid for allotment gardens, community, or private gardens. Its key feature, though, is its ability to bind and hold CO₂. It is possible for any organic material to become carbon. Raw materials that would otherwise be disposed of are especially suitable as feedstock for the production of pure plant carbon on site. Potential raw materials include rough shrub cuttings, weeds that seed or form rhizomes, sections of plants affected by disease, and many others. The low-emission carbonised material can be used as a soil conditioner and for the production of one’s own terra preta. When following this method, the bound CO₂ is retained for thousands of years, the water storage capacity of the soil is increased, and humus build-up is stimulated. Applied in the long term, the process could play a climate-positive role.

For this project, an oxygen and gas management system was developed that permits the implementation of a minimal starter fire. This fire is fuelled and maintained by the expelled pyrolysis gases. The gases that are specifically directed into the annular space maintain the level of heat and therefore also the pyrolysis process. The system ceases to be when no more synthesis gases escape.