Sometimes referred to as ‘black gold’, biochar stores carbon for thousands of years as well as provides a host of agricultural and environmental benefits.

What is Biochar?

Biochar is a black, solid substance which bears a strong resemblance to charcoal that is produced during pyrolysis(burning at high temperature without oxygen) of biomass. It is lightweight, fine-grained and very porous, which are all properties that are useful in its primary usage as a soil amendment.  

Biochar qualities infographic.

Biochar's many properties make it an excellent soil additive, but it can also be used for a variety of other applications

Biochar is a recalcitrant which means it can endure in soils for hundreds of years

Biochar diagram

Biochar applications

Soil improver – Either applied directly, or through mixing with compost, biochar improves water retention, increases beneficial bacteria and enzymes, and reduces the need for chemical fertilisers. Effects are long-lasting and can result in 15% greater crop yields.

Animal feed supplement - When ingested by livestock, biochar improves nutritional intake delivering health and growth benefits, and by increasing nitrogen compounds in the manure, makes it more effective as a natural fertilizer.

Low carbon building – Biochar is being considered as a replacement for aggregates in building materials due to its ability to create carbon-negative buildings, as well as its high porosity.

Industrial uses - Biochar can be used in water filtration to remove heavy metals and pollutants, or as a reductant in metals manufacturing.

As a catalyst – High electrical conductivity, high porosity and high stability mean biochar makes a versatile, cost-friendly catalyst. Processes such as biodiesel production, tar removal and anaerobic digestion can all utilise biochar to optimise their operations.

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Biochar feedstock

Biochar can be made from all kinds of biomass feedstocks. Each type of biomass has its own physiochemical characteristics which influence the biochar produced, meaning a biochar production facility can tailor their process to create “designer” biochar.

Biochar feedstock diagram.

Biochar properties

Biochar with different physical, biological and chemical characteristics will have different applications. Biochar users focused on optimal carbon sequestration will choose a biochar with high fixed carbon content, whilst those using it for soil remediation will prioritise other attributes like water holding capacity (WHC) and specific surface area (SSC). Most applications make the most of biochar’s versatility by utilising more than one of biochar’s properties.

Biomass and biochar infographic.

Want to know more about biochar?

We can customise your biochar output and identify the best applications to suit your needs.

Want biochar?

Visit the Onnu Biochar Marketplace for product information and sales.

Onnu Biochar products.

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Our Green Energy Hubs produce large amounts of excess heat which can be delivered as a fully sustainable, carbon negative energy source for your business.

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Carbon removal

Pyrolysis is the only practical and available carbon removal technology available today, and is a critical tool for the world's journey to Net Zero.

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Biochar is a long-term store of carbon, and an effective soil additive improving plant yields and health. We are committed to producing it on a large scale to make a real difference in the fight against climate change.



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