Late last year the Board of the International Biochar Initiative (IBI), of which I am honored to be a member, decided it was high time to get ambitious when it comes to biochar production. We set a goal to help try to build an industry capable of producing 1 G [i.e. one billion metric tonnes] of biochar within the next 50 years. This is what’s known in the business world as a BHAG – a big hairy audacious goal. Given the recent alarming elevation of both temperatures and atmospheric CO2 levels, we felt that it was time for the biochar industry to step up and show the world how and how much biochar can help rebalance carbon.
Since that time the notion of how to reach that goal has been on my mind a lot. There is an ever increasing variety of new technologies coming on line that can carbonize all sorts of organic material including fast and slow pyrolysis, gasification, hydro-thermal carbonization, low tech kilns, and even micro-wave pyrolysis (just attended a ribbon cutting event on one of those today at RIT). From small, nearly free kilns, to multi-million dollar industrial furnaces, the industry finally seems poised to pyrolyze plenty of organics. The ‘how’ is no longer the constraint to reaching 1G.
The ‘what’ still needs to be identified and quantified, at a global, country, state and local level. After a very (and I stress VERY) preliminary look at just a few potential feedstocks, I’ve come to conclude that 1G is not going to be a problem based on available supplies of unloved biomass. The world has more than enough organic matter that is currently being landfilled, burned or otherwise underutilized which, if carbonized, could bring many benefits beyond rebalancing carbon (as I’ve recently blogged about here).
Let’s look at the residues from just 2 of the world’s biggest crops: rice and corn. According to the USDA Foreign Agricultural Service, preliminary reports show that global milled rice production in 2016/17 was 481.5M tonnes. Rice has two distinct residues: rice straw and rice husks. The amount of rice straw produced (by weight) as compared to the amount of milled rice produced is variable from 1.0 – 4.3 the weight of milled rice. Much of this straw is burned in-situ so that farmers can get on with the business of planting their next crop, even if this practice is banned! Nowadays, thanks to small, mobile kilns like the Kon-Tiki and Warm Hearts Trough, carbonizing rice straw can be done in fields which would not only reduce air pollution but would prevent enormous amounts of CO2 from becoming airborne. If, by some miracle, we were able to carbonize all of this straw it could produce from 157M – 675M tonnes based on a typical yield for this particular feedstock of 32.6%. The rice husks could generate an additional 44M tonnes of char based on typical yields from this particular feedstock.
Corn is an even more ubiquitous crop with an estimated 1,065Mt produced per year. As with rice, corn also has two residues; stover (stalks, leaves, etc. which weighs about the same as the harvest corn) and cobs which weigh about 15% of the corn. Corn residues amount to 1,225Mt of underutilized biomass which could produce more than 350Mt of char. Combined these two crop residues alone could potentially sequester more than 400Mt of carbon (or 2.776Mt of CO2e), and that is only looking at the carbon in the char and excludes the reduction in GHG that the production of biochar could provide if heat is harvested or electricity produced, or soil or manure-generated GHGs that could be lowered if biochar is sequestered in soils or added to manure compost or lagoons.
Obviously carbonizing 100% of these residues is a highly unlikely scenario, but this does show that the world produces enormous amounts of biomass every year that could be used to generate not just biochar but heat and/or electricity at the same time. Crop residues are but one big bucket of biomass. Forestry by-products (thinnings, culling, branches, sawdust, papermill waste, etc.), excrement (both human and livestock), urban waste (e.g. municipal solid waste, industrial, etc.) and invasive species also provide enormous opportunities to help us reach and surpass 1 billion tonnes of biochar. Imagine how far that could help countries (or apparently in the US it will be up to States, Cities and companies!) reach their Paris Agreement goals. Once the collective ‘we’ sharpen our pencils and calculate each of these available categories, I suspect biochar could be one of the best tools for not only reaching their climate mitigation targets, but also helping to improve soil resiliency, food security, while also providing renewable energy and boosting local economies.