How biochar can help protect the climate

Since August 2026, Axpo has been a co-owner of Inkoh, a biochar producer based in the Swiss canton of Graubünden. Together, the partners aim to advance the production of high-quality biochar and the permanent removal of CO₂ from the atmosphere. But biochar can do more than store carbon: it can improve soils, retain water and nutrients, and be used in a range of applications.

Biochar is gaining importance internationally. Studies suggest that the global market will grow significantly in the coming years. Against this backdrop, Axpo is getting involved early in the development of this young and dynamic market in Switzerland. Together with Inkoh, it is developing solutions to use regional biomass efficiently and sustainably.

How biochar is made

Biochar is produced by heating plant-based biomass, such as wood, crop residues or green waste, to high temperatures without oxygen. At around 550 to 900 °C, the material does not burn, it carbonises. This process is called pyrolysis.

The result is a porous, carbon-rich material. The process also releases energy-rich gases and heat, which can be used directly, for example to generate heat and electricity. This allows the biomass to be used as fully as possible.

Biochar as a carbon sink

As plants grow, they absorb CO₂ from the atmosphere. If the biomass is later burned or decomposes, that carbon would normally return to the atmosphere. Pyrolysis instead locks much of it into the biochar.

If the biochar is then used in soil or long-lasting building materials, for example, the carbon it contains can remain stored for long periods. Biochar can therefore act as a carbon sink.

Depending on the feedstock, production process and application, one tonne of biochar can permanently store the equivalent of around 2.5 to 3 tonnes of CO₂.

More than climate protection

Its climate benefits are an important reason to produce biochar. But its porous structure also makes it useful for other applications.

In agriculture and horticulture

In soil, biochar can absorb water and nutrients and release them to plants when needed. It can also improve soil structure, increase aeration and provide a habitat for microorganisms.

One example is Axpo Biomasse’s lawn soil, which contains ten per cent biochar and is used to establish new lawns and renovate existing ones. In a field experiment in autumn 2024, the biochar-enriched growing medium produced stronger grass growth than conventional Axpo lawn soil: 122 per cent more growth for newly sown lawns and 40 per cent more for renovated lawns. An additional benefit is that the carbon stored in the biochar can remain in the soil over the long term.

In agriculture, biochar is also used in animal feed, bedding and soil substrates.

For more resilient urban trees

Biochar can also play a role in cities. As a component of specialised tree substrates, it helps retain water and nutrients around roots, supporting urban trees during periods of heat and drought.

In construction

Biochar can also be used in building materials, for example in concrete mixes such as Inkoh’s Klark climate concrete, or in road construction. Because producing many building materials generates large amounts of CO₂, storing carbon for the long term in durable products is particularly promising.