The Forum Network is a space for experts and thought leaders—from around the world and all parts of society— to discuss and develop solutions now and for the future. It aims to foster the fruitful exchange of expertise and perspectives across fields, and opinions expressed do not necessarily represent the views of the OECD.
To turn away from the alarming development towards an uninhabitable planet for humans caused by climate change, it is not enough to only decrease our emissions; we already have a debt that we need to repay. This is where the creation of long-term carbon sinks is the key. Biochar is scientifically proven to create a carbon sink for hundreds up to thousands of years, the technology is available now and it can be financially lucrative. So why isn’t biochar getting more attention and growing faster on a global scale?
For any city project, the question of potential replicability is always important: how can others learn from and reproduce the original idea?
The Stockholm Biochar Project was the first of its kind in setting up biochar production in an urban context. As one of the winners in Bloomberg Philanthropies’ innovation competition Mayor’s Challenge in 2014, a collaboration between the city of Stockholm, the municipal waste company Stockholm Vatten och Avfall and the energy company Stockholm Exergi got financing to realise an idea. The city’s garden and park waste was turned into biochar and heat. The heat was distributed via the district heating network and the biochar was used to significantly improve the health and survival rate of the urban trees in Stockholm. This was Sweden’s starting point towards becoming one of the leading users of biochar in urban environments. Handling waste, producing renewable energy, creating carbon sinks as well as making urban greenery more resilient—all in one!
For any city project, the question of potential replicability is always important: how can others learn from and reproduce the original idea? In 2023 the Stockholm Biochar Project is now replicated in different countries around the globe; Germany, Norway and the United States to mention a few. Bloomberg Philanthropies are funding and supporting seven city projects around the world to develop their own city biochar project and engage residents in the fight against climate change. Meanwhile, in Sweden the biochar industry continues to develop. The project Rest till Bäst (“Residues for Best Use”) aims to identify local biomass residues and waste streams that can be used for biochar production. And a wide range of biomass is suitable, such as tree clippings and residues from agriculture—as long as it has been sustainably obtained and regulations regarding the degree of pollution in the biomass are followed.
But what is biochar? Biochar is a carbon-rich material, similar to charcoal, and one of the end products of pyrolysis (heating organic materials in the absence of oxygen). The carbon structure in the biomass transforms, becoming stable and therefore not easily degraded by microorganisms when the biochar is most commonly used as soil amendment. And with a stable carbon structure a reliable carbon sink is created! The excess energy from the production can be used for climate-positive district heating, and techniques to produce electricity are under rapid development. The biochar itself can be used in soil, animal feed, food, building materials, cosmetics, electrical appliances and clothing etc. So, if biochar and the production of it is so great, why isn’t it getting more attention and growing faster on a global scale?
More on the Forum Network: The Secret Superhero: Harnessing the natural power of moss with IoT for cleaner and smarter cities by Peter Sänger, Co-Founder and CEO, Green City Solutions
First, there is a lack of knowledge. The power of biochar production is also its biggest threat. If you explain biochar production to an energy producer, their immediate reaction will be that it is a waste to carbonise biomass instead of combusting it since that would generate more energy. Biochar production has four legs to stand on: waste management, energy production, biochar production and the creation of carbon sinks. To see the purpose of it, you must understand the value of each separate leg, which can obviously be challenging since there are potentially four different markets to consider.
When considering all its positive effects, the greatest potential for biochar is perhaps the agricultural sector.
Second, biochar production is available in a range from completely manual production methods to medium-sized industrial machines. Today, most of the production units are small to medium-sized pyrolysers; critics say that this is an obstacle for making biochar climate relevant. What you should remind yourself of is that to create carbon sinks from biochar, the physical biochar must be used as soil amendment (or in other applications that make sure the biochar does not return to the atmosphere as carbon dioxide any time soon). From a climate perspective it is better to minimise transports of both biomass and biochar by creating circular biochar systems locally. Also, by having small- to medium-scale production machines, one can benefit from the biomass that is available in the local area. Combined with other methods of creating carbon sinks, biochar production forms a perfect complement to future, large-scale and more costly technologies.
Photo: Jacqueline Hellmann/Ecotopic
When considering all its positive effects, the greatest potential for biochar is perhaps the agricultural sector. Using biochar as soil amendment on agricultural land can generate lots of positive effects on soil health, drought resistance, nutrient leakage, greenhouse gas emissions, soil compaction and, not least, on the harvest. At the same time, the financial conditions for farmers to pay the full cost of producing biochar is often not possible. These are available in many other business sectors, but without the possibility to off-set biochar.
By making biochar from biomass that has captured carbon dioxide from the air and adding it to soils that are rapidly depleting, we may have a chance to restore ecosystems for a more pleasant place for us humans to live long term.
This is where the carbon sink allows for money transfer from sectors with the demand to buy trustworthy, traceable carbon sinks to sectors that need for the physical biochar product. To support this financial migration, we need a trading system for carbon sinks from biochar that is traceable through the entire process, from biomass to biochar. The good news is that these kinds of systems have just been developed and taken into use. Carbon sink trading platforms allow for companies that wish to climate compensate to convert their input into seed capital for new biochar producers. This will greatly impact the number of biochar producers and users, and carbon sink creators—not just in Sweden but worldwide.
Today, we have too much carbon in the atmosphere, too little carbon in our soils and biomass being treated as waste instead of resource. By making biochar from biomass that has captured carbon dioxide from the air and adding it to soils that are rapidly depleting, we may have a chance to restore ecosystems for a more pleasant place for us humans to live long term. Biochar may not be the only solution, but let’s not make that an argument against it.