Greentech company announces first of 16 pyrolysis hubs that will form the UK’s biggest carbon removal initiative

ONNU, which transforms biomass into valuable biochar that acts as a carbon sink, has announced plans to build the first of 16 pyrolysis hubs in the UK’s Wye Valley as it continues its mission to realise the potential of biochar to facilitate the net zero transition.

The company says that disposing of poultry litter has become problematic and expensive due to public outcry about the impact of phosphorus run-off on local ecosystems and stricter regulations around spreading waste on land. It plans to buy waste biomass produced by local poultry farmers to produce biochar.

Giles Welch, CEO of Onnu, said that using the waste as a pyrolysis feedstock will turn a problem into a revenue stream for farmers. The biochar produced will be used as a “safe and transportable organic fertiliser forming part of a circular economy in UK agriculture”. Welch went on to describe it as “the only genuinely sustainable solution to the problems facing the Wye Valley”.

Onnu has already identified four potential locations for the site, which it expects to start operating in April 2024. It plans to open an office in Hertfordshire later this year with six staff, including two land acquisition experts.

The hub will form part of a multi-million-pound investment spread over four years expected to create more than 100 greentech jobs and “end the land-spreading that has caused well-documented damage to the River Wye and surrounding areas”, according to Onnu.

More to come

Onnu will build 16 hubs across Hertfordshire, Shropshire, and Powys by 2027, which will be strategically located a few minutes’ drive from several dozen poultry farmers. Each hub will comprise two pyrolysis units and be able to process 10,000 t/y of waste biomass.

Welch said the hubs will be no larger than a typical barn, and completely self-contained, self-sustaining units with underground storage. He added that they “will create no discernible noise or odours so their operation will have no impact on the surrounding areas”.

Once all 16 sites are complete, they will be capable of processing 1.6m t/y of waste, which Onnu says is sufficient to account for all the poultry litter produced in the Wye Valley catchment.

In addition, the hubs will collectively sequester more than 500,000 t/y of CO2 that would otherwise be released into the atmosphere, potentially making it the UK’s biggest carbon removal initiative.

Explaining how biochar production enables CO2 removal, Onnu says that when biomass grows it absorbs CO2 from the air via photosynthesis, which remains sequestered throughout its lifetime. However, the carbon is typically released back into the end of the biomass lifetime. Producing biochar from waste biomass prevents the carbon from re-entering the atmosphere. Due to the stable nature of biochar, it can remain in soil for thousands of years, making the method an important carbon removal technique.

Onnu expects the biochar it will produce will qualify for CO2 removal certification by Puro.earth, a crediting platform for engineered carbon removal. The greentech company predicts that after the Wye Valley hubs have been operating for ten years they will have generated 350,000 t of biochar and 580,000 CO2 removal certificates, with Onnu planning to sell the biochar along with the credits.