Summary

Residual biomass from coconut palm trees is used for the sustainable production of biochar and applied as fertilizer on the plantations

Together with our partner Kisiwa Farming, atmosfair co-develops and finances a biomass pyrolysis facility on the Tanzanian island of Mafia that transforms surplus coconut wood residues into durable biochar. Kisiwa Farming operates the plant and supplies the feedstock from its own coconut plantations, while atmosfair provides project financing, supports carbon credit certification, and purchases the resulting carbon removal credits. Kisiwa Farming applies the biochar back onto the soils of the coconut plantation, creating a long-term carbon sink while simultaneously restoring soil health. We aim to remove 3,600 tCO₂ per year by applying 1,600 tonnes of biochar to the degraded plantation soils.

Giving value to residues

The island of Mafia off the coast of Tanzania with its 60,000 inhabitants is characterised by fishing, tourism and agriculture. Around the time of German colonial rule, the first coconut plantations were established here.

In the meantime, the company Kisiwa Farming Limited, has taken over the operation of the coconut plantations and is restarting cultivation. To keep up the production of a variety of coconut products, Kisiwa Farming needs to regenerate and rejuvenate the 2700 hectares of coconut plantations. Coconut palms that are more than 70 years old and no longer bear fruit will be replaced by young trees. The old trees are processed into timber.

In 2021, atmosfair and Kisiwa Farming Limited set up a pilot biomass power plant on the island to utilise the surplus coconut residual biomass to reduce CO₂ emissions and dependence on diesel generators. However, due to contractual difficulties in feeding the green electricity produced into the grid, less residual biomass can be used than planned.

Atmosfair and Kisiwa Farming will now use the surplus residual coconut biomass for the sustainable production of biochar. The non-recyclable pruning residues from the coconut palms and other biomass residues from the restoration of the plantations are used to operate the pyrolysis plant. We use the heat generated internally for drying coconut wood and apply the biochar mainly on the plantation itself. By incorporating the biochar, we permanently store CO₂ while improving the soil quality at the same time.

Our partner

Our partner Kisiwa Farming Limited (KFL) is a Tanzanian social enterprise that aims to combine sustainable coconut cultivation with renewable electricity and biochar production on Mafia Island. KFL was founded by Darius Boshoff, who has already implemented numerous energy projects on the African continent with his engineering company Energidrop (Pty) Ltd.

KFL was founded in 2019 and is operational with an established team of employees, the majority of whom are from Mafia. The expansion of the project, including the production of biochar, will create more local jobs. It is intended to act as a catalyst to creating a truly sustainable economy on the island that embraces the principles of a circular economy that benefits all the island’s stakeholders and is likely to ensure that future development on the island is aligned with these principles.

Background information biochar

Plants absorb CO₂ from the air through solar energy and incorporate carbon into their cell structures. In doing so, they naturally remove CO₂ from the atmosphere. Humans can process plant biomass into biochar before decomposition begins, preventing the release of CO₂. The carbon remains stored in the earth for centuries in the form of biochar, even when it is simply applied to the topsoil or plowed under. Biochar resists biological decomposition in the soil due to its unique structure. To ensure its effectiveness, the ratio of hydrogen to organic carbon in the composition of biochar must fall below a certain threshold, as outlined here (Persistence of biochar in soil). This can be conclusively tested in the laboratory. When this ratio is achieved, science indicates that a maximum of 0.3% of biochar is decomposed annually, as stated in the following document  (Senkenpotenzial), resulting in minimal CO₂ emissions. After 100 years, at least 74% of the carbon is securely bound in the soil. This calculation subtracts all emissions generated during the project when determining the negative emission.

Biochar has many other positive effects. In addition to binding CO₂ in the soil, it can also be used as a carrier material for nutrients and thus to enrich the soil. In tropical soils, particularly, it can lead to increased crop yields. The biochar absorbs the water from heavy rainfall in the monsoon and releases it back to the plants over a period of weeks. As a water reservoir, it prevents nutrients from being flushed out of the soil. Other important factors also come into play: the basic cycles of the ecosystem are maintained. The biochar is returned to the soil exactly where the plants grew. Important minerals and trace elements are retained and the soil does not leach out. Biochar thus combines carbon storage with sustainable agriculture.

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