Black is the New Green: Why the world needs Biochar Carbon Removal

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“What is that, biocarbon? And you are sure the carbon stays trapped? And there’s enough feedstock for that? And if this technology is so powerful, why does nobody talk about it?” – those are just some of the questions that I repeatedly asked my co-founder over the first weeks of our collaboration as we started to build ecoLocked. Today, 1.5 years later, I must have answered them about 1,000 times myself. And indeed: while the concept behind biochar carbon removal (BCR) – trapping carbon sequestered by plants – is amazingly simple, building a scalable and sustainable BCR venture is not trivial at all.

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The carbon removal imperative

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But let’s start with the basics – why are we so enthusiastic about a technology that turns biomass into something that looks like charcoal for your barbecue? The answer is simple: It can help us prevent massive amounts of natural emissions. And that is now needed more than ever, as targets for reducing anthropogenic emissions are consistently being missed. Take the ever-growing construction sector: Buildings are directly and indirectly responsible for 37-40% of all greenhouse gas emissions. With raw material use for construction predicted to double by 2060, there is no other sector where the target conflict between economic growth and decarbonization is so evident. And still: construction emissions hit an all-time high in 2021.

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That is why scientists’ warnings are getting more alarming by the day. In fact, the latest IPCC report shows how none of the remaining 1.5° scenarios are any longer feasible without additionally removing CO₂ from the natural carbon cycle. For a 1.5° world, we need to deploy carbon dioxide removal (CDR) technologies starting now and increase volumes to 10-20 Gt of CO₂ removed per year by 2050.

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For that, we need long-term carbon removal technologies that prevent the release of the captured carbon for as long as possible – ideally for centuries to millennia. This distinction is important to understand why just planting a billion trees won’t do the job. For those who want to learn more about the breadth of available CDR technologies as well as their permanence, we recommend the recently published State of Carbon Dioxide Removal report.

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Principles of Biochar Carbon Removal (BCR)

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What’s clear is that significant resources must be invested in the exploration of all long-term CDR technologies – so that industrial-scale carbon removal will soon be a reality. But funding is limited, and a ton of CO₂ saved today is worth more than a ton of CO₂ saved tomorrow. So, in addition to longevity, CDR technologies must be evaluated by their potential to deliver significant removals in the near future. Three distinct criteria are commonly used for this purpose: 1) Technological readiness, 2) Economic viability, and 3) Global scalability.

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Now here’s where BCR comes into play – because it ticks all the boxes. In essence, biochar is a carbonaceous solid, created by concentrating (‘locking up’) more than half of the carbon contained in organic matter through a high-temperature, oxygen-deprived thermal conversion process (most often pyrolysis; and for simplification we will refer to pyrolysis although other technologies exist). We like to refer to the material produced by BCR as biocarbon to highlight its chemical qualities, which include a particularly high internal surface area. Depending on the carbon content of the input material, one ton of biocarbon can lock up to 3 tons of CO₂. Coming back to the tree example: while trees sequester CO₂ throughout their lifetime via photosynthesis, BCR is how we can ensure that the very same CO₂ does not get released again into the atmosphere at end-of-life – which would usually happen via combustion or decay.

So let’s take a look at how BCR fares in our three categories:

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1. ‍Technological readiness: As we approach climate tipping points, the time-to-market – or time-to-impact – of a CDR technology becomes a key factor. Biocarbon production is, in fact, an ancient concept that dates back to the creation of charcoal through controlled wood burning. Nowadays, pyrolysis technology is capable of producing more than 1,000 tons a year, handling diverse biomass inputs of varying moisture, and capturing pyrolysis oil and syngas as byproducts. This makes many systems net energy generating as they require only a small amount of starting energy and, once up and running, reuse the syngas for operating heat or electricity. Over the last decade, BCR technology has been optimized for industrial scale and now leads other CDR methods in terms of near-term removal potential.
2. Economic viability: BCR is one of the most beneficial ways of recycling biomass residues as it effectively converts all substances contained into valuable outputs: biocarbon, pyrolysis gas, and sometimes pyrolysis oil. Biocarbon itself is a highly versatile material that can, for example, be used as a fertilizer-enhancer for regenerative crop farming, as activated charcoal to filter wastewater, and to replace virgin and/or fossil resources in the production of materials. Meanwhile, pyrolysis gas could serve as a source of biogenic CO₂ and hydrogen for fuel production or as an energy carrier to power close-by industries and communities. Revenue streams from those products cross-subsidize the carbon removal costs from a pyrolysis plant, which are estimated at anywhere between € 10 and € 345. With declining Capex and increasing monetization of material outputs, we expect costs to level out at € 30-120 per ton of CO₂ at industrial scale. Note that these figures are different from BCR credit prices in the voluntary carbon market, which is primarily driven by supply and demand.
3. ‍Global scalability: BCR can use any organic matter as feedstock, as long as sustainable sourcing and additionality are guaranteed (stay tuned for our next article!). This ensures scalability, as production plants are able to accommodate locally available biomass waste. Studies estimate the global availability of biomass residues at 2-100 Gt per year, translating to multiple gigatons of natural CO₂ emissions that could be prevented. In addition, biocarbon can be used profitably in multiple global markets, which makes its production and storage financially viable. However, as we will see in our next articles, versatility comes with its challenges, since end users must be able to tolerate variability in quality and in production costs as created by different BCR feedstocks and production processes.

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Opportunities and challenges for BCR at scale

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Given the maturity, economic attractiveness, and scalability of BCR it does not come as a surprise that production capacity is increasing fast – in Europe by an astonishing 70-80% per year. And it has to: according to the first annual review by cdr.fyi, a global carbon removal market initiative, both (pre-)purchases (40%) and deliveries (87%) of carbon credits are dominated by BCR. Buyers seem to value that, with BCR, they can achievable a verified impact within just a few months to one year after investing in a project. Fueled by this momentum, the European Biochar Industry Consortium (EBI), which forms the umbrella for a new industry that is fundamentally driven by climate impact, is calling for members to maintain current growth and remove 6 Mt of carbon per year by 2030 and 100 Mt by 2040.

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Time for a thought experiment: if we turned all the unused biomass residue in the world into biocarbon and safely stored it, what is the positive climate impact we could achieve? Based on the above considerations and in line with academic meta-studies (e.g. Fuss et al., 2018, Slade et al., 2014, Lee & Day, 2012), we expect a total climate impact potential of no less than 1.5 to 3 Gt per year. A significant portion of the 10-20Gt required by 2050 – and, along with the potential of other promising CDR technologies such as direct air capture and mineralization, providing a glimpse of hope that a 1.5° future may still be a practical possibility.

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And that's why we are on this journey: to accelerate the global roll-out of BCR and unlock value-adding use cases for biocarbon, in particular in developing markets where biomass residue is abundant and 80% of future global urban development is expected to take place.

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But a key question remains: How can we effectively leverage all that climate potential and avoid adverse side effects? We will explore that question across our next articles and along the following requirements for sustainable BCR at scale:

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• ‍Sustainable sourcing of biomass residue at gigaton scale, homogenous and in controllable quality.
• ‍Continued progress in pyrolysis technology to drive unit costs to <€500 per ton of biocarbon.
• Scalable end uses that provide predictable revenue streams for producers and simultaneously serve as stable (i.e., secure and permanent) carbon sinks.
• The ability to accommodate (or productively use) variation in biocarbon chemical and physical properties as it arises from differences in feedstock availability.
• The development of hyperlocal value chains that minimize transportation and ideally co-locate BCR facilities with biomass sources and biocarbon end users.
• A reliable carbon accounting system that ensures proper measurement, verification, and certification of carbon removals and enables a fair distribution of rewards to all parties involved.

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In the next edition, we will explore sustainable sourcing of feedstock for BCR as well as the global availability of biomass residues – stay tuned!

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 By Mario Schmitt

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