The story in the soil: Meet the start-up trying to pioneer a UK market for biochar CO2 removals

The story in the soil: Meet the start-up trying to pioneer a UK market for biochar CO2 removals

DarkBlack Carbon was only officially founded four months ago, but believes it is already primed to be a market leader for biochar in the UK

“It’s got everything, hasn’t it?” says Liz Casely, co-founder of UK start-up DarkBlack Carbon. “It’s got the climate angle, it’s got the exponential potential to be profitable, it’s got the interest, and it’s a good story down the pub. In fact, that’s why our angel investor got involved – because he wants to tell his mates that he’s doing something that no one else has done.”

Casely is telling BusinessGreen why she believes her carbon removals venture has garnered such an enthusiastic response during its very short existence, and she has a point. The UK start-up manufactures biochar from woody biomass waste and compost for use as an agricultural soil enhancer, and hopes to sell the CO2 sequestered from the process in the form of credible and “ethical” offsets. It is a business model that appears to tick all the above boxes, and friends, associates, and stakeholders have all been keen to lend a hand in getting it off the ground, she says.

“The exciting thing is that people want to come on the journey with us,” Casely continues. “People want to know ‘How can I help. How can I get involved? What do you need?’ which is a lovely, lovely thing.”

Biochar is itself nothing new – there is evidence pre-Columbian Amazonians produced the carbon-rich substance, an ashy charcoal-like residue, by covering burning biomass with soil in pits – but DarkBlack Carbon takes a very modern approach to its production.

The company was officially founded just four months ago by Casely and her business partner Rob Palmer – although the two had been collaborating on soil based carbon projects for a couple of years – and they are already convinced DarkBlack is shaping up as a leader in the UK’s nascent biochar carbon credit market.

That is in part due to the admittedly sparse field of British competitors in this still fairly-niche sector, but the two co-founders claim it is also testament to the quality of the pyrolysis machine they have built, and the rigorous carbon measurement process they have embedded into their offering. Moreover, the potential climate benefits of the biochar itself are hugely compelling.

They claim biochar can comprise up to 75 per cent carbon, whereas the typical organic carbon content of dryland agricultural topsoil stands at less than three per cent. Moreover, studies have shown that adding it to agricultural land can further amplify the carbon storage capacity of surrounding soils. That, and biochar can help improve soil health, boost agricultural yields, and bolster resilience to flooding and chemical run-off into waterways.

Biochar is, in short, a climate and environmental action multiplier, and one that could in future open up further avenues for farmers that move into regenerative practices to bolster their income through carbon sequestration, according to DarkBlack Carbon. It estimates every hectare of land farmed regeneratively with biochar can remove over 10 tonnes of CO2 per year, and every one per cent of soil organic carbon restored per hectare can hold 23,000 gallons of water.

“It is a catalyst for helping to restore natural balances,” explains Casely.

It is therefore easy to see how a thriving market for this natural biomass material could spur opportunities across multiple segments of the green economy, from agriculture and regenerative farming, to the circular economy and nature-based climate solutions. DarkBlack Carbon is also eyeing up the potential use of biochar as a sustainable construction and insulation material, and for helping to clean up contaminated land on former industrial and construction sites.

“Biochar is going to open so many other avenues for investment, for carbon, and for planet-saving, because of all the exponential benefits that we haven’t even accessed yet,” Casely predicts. “Someone is going to see the value in that, and see that by coming on that journey [and investing in biochar carbon removal credits], they are going to get the kudos for it.”

For now, though, the company is largely focused on producing biochar in order to create and sell carbon removal credits to organisations looking to offset their own emissions and invest in building a broader market for this early-stage climate solution.

On the gloomy late February morning that BusinessGreen visited DarkBlack’s site in rural Leicestershire, populated by large piles of compost, wood waste and bags full of biochar, the company was celebrating the approval of its very first CO2 credit through carbon removal standard and credits registry So far, it has made 2,000 carbon credits available for pre-sale to interested organisations and investors, each one representing a tonne of CO2.

As Casely points out, the added selling point is that biochar is a tangible product, not just a carbon offset certificate. “It’s easier to get money for a thing, than it is for a concept,” she says.

The Blackbird

The pyrolysis machine itself, which has been christened Blackbird, is capable of producing 1,500 tonnes of biochar – and 3,500 tonnes of carbon removals credits – each year at full capacity. It is already in full operation, and while the team is still tweaking and further optimising its efficiency with a view to building bigger, more commercial-scale machines in future, the team expects to be able to initially offer 2,000 carbon removal credits this year.

That may not sound like a great deal, and the Blackbird is far from being a major industrial operation at present, but DarkBlack believes that should the domestic market for biochar take off in the coming years it will be in prime position to capitalise.

Optimising the machine has been a complex process because the best biochar requires a precise recipe. It all begins with council-collected compost and woody waste offcuts from hedges, tree trimmings and pallets, which the company chips and screens to ensure it has the optimal mix. That is then fed into the pyrolysis machine, which heats up the material to temperatures upwards of 500C in order to thermally accelerate the decomposition process, thereby permanently changing the structure of the carbon and locking it up for hundreds if not thousands of years. Essentially, the process creates a material that is more or less immune to the short-term natural decay that occurs with most organic matter – decay which releases greenhouse gases such as methane and CO2 into the atmosphere.

While a small amount of propane is needed to kick-start the Backbird machine, once it has been on for a short while and the temperature stabilises, it is then entirely self-sufficient in its energy requirements, harnessing its own heat to meet its needs. The company is also exploring how it can make more use of the wasted heat energy from the machine, perhaps by in future piping it to other industrial operators to help drive down their bills and emissions.

Still, if building and optimising the machine has been a technical challenge, unlike longer term forms of nature-based carbon sequestration – be it through peatland, forest or mangrove restoration – turning woody biomass into biochar takes minutes. And the firm argues the biochar carbon content is also much easier to keep track of, making it a far quicker and more reliable way to create a supply of carbon credits. On its website, DarkBlack Carbon describes biochar as “the fastest and most easily-available source of carbon removal certificates”.

Palmer is also adamant about the accuracy of his company’s biochar carbon measurement, which involves taking readings and adding up the CO2 costs throughout the process from start to the finish, and beyond. “We are as accurate as we possibly can be, not just for the buyer, but for ourselves,” he explains. “We want to make sure that we are doing the right thing. Integrity is the heart of this game. No one wants to get caught out – morally that would just be the wrong thing to do.”

In addition, although it does not form part of its certification for biochar carbon credits, the company is taking soil carbon samples where the material is spread on land in order to further understand its impact. “We’re partnering with some industry experts in soil organic carbon and also with universities to better understand this last part, which we’re really interested in,” explains Palmer. “It’s not the end of the journey just because the biochar goes in the soil, we should see what its true impact is.”


The Blackbird machine in action – Credit: Michael Holder


Scaling the UK market

Still, if DarkBlack Carbon’s proposition sounds almost too good to be true, there remains a huge, critical barrier to biochar projects in the UK: the market simply is not there yet.

In future the company hopes to sell its biochar for around £200 per tonne for use in regenerative agriculture, which would add another income stream to its sales of carbon removal credits. But the company is currently giving its biochar away for free to farmers – who have little incentive at present to invest in such measures – in the hope of boosting awareness and understanding of the benefits it provides.

Even giving it away faces restrictions, as the Environment Agency allows only one tonne of biochar to be put on land per hectare. DarkBlack Carbon, however, believes agricultural lands can easily accommodate a lot more, potentially 20 to 30 tonnes of biochar per hectare, and that such restrictions are prohibitive to the development of a thriving, negative emissions biochar market in the UK.

Palmer argues lifting restrictions to allow more biochar to be spread on land could significantly increase the climate and environmental benefits of the material, and that by fastidiously tracking the carbon content of these soils, farmers could even derive revenues from the “additionality” of CO2 sequestration the biochar can foster in surrounding soils.

“We know that biochar can act way better, at a far higher density, but we’re hindered by the fact that the Environment Agency just doesn’t allow us to do it,” he explains. “So there needs to be a policy shift to be allow us to scale. The problem is we’re going to get to a bottleneck at some point once – we hope – there are other UK biochar project developers and loads of use cases, yet no demand because the regulations aren’t there.”

Contrast that with other parts of the world where supportive policies and regulations are allowing biochar producers to comparatively thrive, such as in the US, which already boasts a multi-million dollar market for the material. Finland is another market where biochar can fetch prices of up to £400 per tonne, and the market for certified carbon removals credits is also more advanced, according to Palmer.

“If you want to do biochar, go to Finland,” he says, only half-jokingly. “It’s probably the place with the most regulatory freedom for biochar.”

It is a depressingly familiar story for many green innovators in the UK, who will have seen the size of the multi-billion-dollar clean tech push being made by the US through its Inflation Reduction Act, and the corresponding response from the EU Commission, and wondered whether Britain risks being left behind thanks to its desperately slow planning system and recent political instability.

However, Palmer remains committed to the UK, partly because it is his home, but also because the way he sees it “trying to get biochar going in the UK rather than taking the easy route and shipping it off somewhere else – I think that’s the right thing to do”.

But as ever for a start-up, there is also an investment challenge. Aside from DarkBlack Carbon’s initial, undisclosed angel investor, the firm knows that further backing – whether through direct investment or the sale of carbon removals credits – could be key to scaling up its vision, which includes the development of 10 to 20 further Blackbird machines across the UK.

Corporate interest in carbon removals credits is certainly growing significantly as net zero targets proliferate across the economy, but it is still very early days for the sector, and for DarkBlack Carbon which has yet to see interest in biochar turn into tangible sales in the UK. There is plenty of enthusiasm, but as ever, few investors want to take the risk of being the first to make the decisive move in support of an emerging field.

In the meantime, the US is speeding ahead with its biochar market, warns CEO Antti Vihavainen, who set up the Finland-based carbon removals credit registry in 2018.

“The US is red hot due to the Inflation Reduction Act,” Vihavainen told BusinessGreen while visiting DarkBlack Carbon’s site in Leicestershire. “There are various other reasons as well, but there’s just entrepreneurial activity there like nowhere else.”

But he is optimistic that as awareness of the climate crisis deepens, investment and capital will soon begin flowing into the nascent carbon removals credits market, including for start-ups such as DarkBlack Carbon. “It seems many buyers and purchase facilities that have had a pile of money sitting on the table are starting to deploy that,” Vihavainen says. “They are ready for that. So that’s another radical shift.”

To overcome the huge market and investment challenges facing the biochar market a certain mindset is required, according to Casely. She enjoyed a distinguished career in finance and investment before becoming a green entrepreneur, and contends that challenges – such as scaling biochar as a business proposition – attract her and Palmer “like magnets”. “I think the thing with both of us is we have a bit of passion, but we can also make things happen that look too difficult to other people,” she says. “It’s like, ‘that’s difficult, I’ll give it a go!'”

Palmer, meanwhile, previously worked in bomb disposal in the British Army, before moving into the comparatively safer sector of carbon removals innovation several years ago. In his day job, he is now head of innovation at another British carbon removal venture, UNDO, which locks up CO2 through an enhanced rock weathering process, while working to build up DarkBlack Carbon.

“We’ve taken a huge risk – a genuine leap of faith,” he says. “Maybe this will stoke the market and other people will see us and go ‘oh it is doable’, but we’re not there yet.”

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