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Biochar is an important CO₂ sink

Swiss Post aims to be carbon neutral by 2040. The goal is to avoid emissions as far as possible and to neutralize any residual emissions. For this reason, Swiss Post is focusing on the innovative technology of using pyrolysis to manufacture biochar, as has been produced by the company Inkoh AG in Maienfeld since 2020. Inkoh’s Managing Director Gion Willi explains all about this form of carbon in our interview.

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Portrait Gion Willi

How do you see the role of biochar in the fight against climate change?

Biochar’s ability to store the carbon present in wood on a lasting basis makes it an important CO2 sink that can help us achieve global climate targets. A key requirement for this is that the carbon contains no harmful residues. The production process must be continuous and process-oriented, as is the case in Maienfeld, so that it can be used anywhere without a second thought. In addition to acting as a carbon sink, biochar can also contribute towards reducing water consumption. Biochar enables high-grade materials such as activated charcoal to be produced locally, reducing reliance on international suppliers.

What plants are used to produce biochar?

In principle, biochar can be made from any organic materials, including straw, grass cuttings and nutshells. In Maienfeld, we exclusively use high-grade, untreated wood timber − in other words, wood chips from branches and wood waste from sawmills. Wood is especially suited to biochar production because of its carbon content and quality.

How does CO2 end up in the wood, and how is it stored?

Trees need CO2 to grow. As trees grow, they absorb CO2 from the atmosphere and convert it into carbon and oxygen. The oxygen is released back into the air, and the carbon remains in the wood. It’s only when the wood is burned or decomposes in forests that the carbon is converted back into CO2 and released back into the atmosphere. 3 tonnes of wood can produce approximately 1 tonne of biochar. About 90 percent high-grade carbon is stored on a lasting basis in the biochar.

Vegetable coal on one hand

How is biochar made?

The wood chips dried with the waste heat from the pyrolysis process are fed into a pyrolysis plant, where they are heated up in a low-oxygen environment at a temperature of between 400 and 900 degrees, depending on the use. The gases that are generated then burn. The controlled heating process and the low-oxygen environment cause the wood to start glowing, and the high temperatures convert the carbon present in the wood into a more stable substance, namely biochar.

What are the properties of biochar?

Biochar is like a sponge and can absorb five times its own weight in water and nutrients. This means it can be used as a source material for numerous environmentally friendly products.

What are the uses of biochar?

One of the main uses of biochar is the agricultural sector: it improves the fertilizer and water capacity of the soil. A tonne of biochar per hectare can be put into the soil without any issues, but more would also be possible. However, this isn’t conclusively backed up by scientific evidence. When mixed with animal feed, it has a positive effect on the animals’ health and digestion. There is also a lot of potential for using biochar in the concrete manufacturing industry. A leading example of this is KLARK “Klimabeton” (climate concrete), which, having been mixed with Inkoh biochar, is able to store and capture carbon on a lasting basis. There is also a great deal of potential in its use as activated carbon, which is currently undergoing a very promising test phase in Switzerland.

As an enterprise affiliated with the Confederation, Swiss Post wants to play a leading role in climate protection. For this reason, Swiss Post resolved last year to become carbon neutral in its in-house operations from 2030 and to achieve net zero across its entire value chain from 2040. The wheels for achieving this have been set in motion in recent months, and a whole host of future-oriented measures have been agreed upon. By taking these measures, Swiss Post will avoid approximately 90 percent of its emissions by 2040, whilst the remaining emissions will have to be removed again from the atmosphere and stored on a long-term basis. At present, there are only a few options for removing CO2 from the atmosphere in a lasting manner that have the required degree of maturity. Inkoh AG, a Swiss company based in Landquart, is one of the pioneers developing a technology that produces high-quality biochar from biomass.

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