Why Biochar?

Biochar is simply another word for charcoal. It is made by heating plant material without oxygen. This technique is known as pyrolysis.  When heated the plant material decomposes into solid, watery and oily fractions, but it does not burn as there is no oxygen, so the carbon cannot oxidise and become carbon dioxide.

Once the pyrolysis process starts it is self-sustaining, using the volatile gases to heat the reaction chamber. Because no fossil fuels are used to sustain the heating, and because the solid Biochar does not react with oxygen to form Carbon Dioxide, the whole process is carbon negative. This means we capture (sequester) more carbon than is used to operate the pyrolysis process.

Pyrolysis can use a variety of source materials, but our process is based on wheat straw which is typically 42% Carbon. For every 3 tonnes of wheat straw pyrolyzed we capture approximately one tonne of Biochar. The Biochar is not just carbon, it contains some ash and also some valuable plant nutrients such as potash.

The Carbon in Biochar is largely resistant to microbial degradation, meaning  when it is added to the soil only a small portion of the carbon is lost and the majority of the Biochar remains in the soil for hundreds to even a thousand years.

By making Biochar from feedstocks we can take the carbon captured during photosynthesis and place it in the soil. As a result, the air has less Carbon Dioxide, and the equivalent amount of Carbon is locked away in the soil. This process is called Carbon Sequestration.

Carbon sequestration by making and depositing Biochar in soils is a Carbon Dioxide Removal technique recognised by the IPCC, and Biochar is now firmly part of their global plans.

In the past two decades the scientific understanding behind Biochar has developed exponentially. We have seen a transition from the ancient and almost magical wisdom of Terra Preta to a well-researched body of work, much of which is focused on improving soil health and crop yields.

For more information have a look at this Guardian interview with James Lovelock.