Biochar: How to make the market work

In short, it's darn-near impossible:

“Biochar Will Save the World!” proclaims a group page on Facebook. Popular Mechanics writes of an “ancient charcoal” that can “put the brakes on global warming.” More than its prospects as a carbon sink or a fuel, it has massive prospects for development (the economic kind) for developing countries and emerging markets. A very wise Finance professor* once told me, “Anytime anybody tells you they have a market for that, be very suspicious.” It’s not that biochar couldn’t work, but that the market to make it work would have to be nuanced and highly regulated.


“One of the dangers of a biochar industry in developing countries is that you can divert your biochar to fuel or that you can somehow create more of a demand for wood which would be completely counterproductive. What is a more sustainable system is to use agricultural and wood wastes,” explains Dr. Simon Shackley, at the UK’s Biochar Research Institute in Edinburgh.

Biochar as a fuel is in the middle of a hierarchy of fuels commonly used in developing countries. Dr. Shackley explains that the poorest tend to use wood, then charcoal, then propane. In developed countries charcoal is a luxury fuel, and it would be “absurd” for people in developed countries to all of a sudden switch to heating our homes with it. There in lies the problem: biochar is viable on the market as both an agricultural tool and as a fuel in developing countries.

The best strategy then, according to Shackley, is to find sustainable feed stocks. He gives an example, “if you’ve got a rice paddy system... the rice husks are thrown into the paddy field and they decompose for methane, which is a very powerful greenhouse gas. So in that case, it’s much more efficient to put the rice husk into a pyrolysis or gasification machine, carbonize it, and put that into the field and you’re returning the nutrients to the soil.” And then you get a carbon negative process. Depending on the machine, the pyrolysis process itself can produce energy that can be used as well.

Sounds great, right? In principle, sure.

Few problems:

In terms of accounting biochar is only carbon neutral or negative if the biochar is replanted into the soil right away and not used as a fuel. More likely is that it is stored. Shackley says that common practice is not to count pyrolysis process in the CO2 footprint. Pyrolysis does produce CO2. And if the biochar isn’t planted but used as a fuel then it is carbon positive. Sure it emits less carbon than fossil fuels, but using it as a fuel would distort its price as an agricultural input.

This leads to the second problem: logistics. Shackley describes the process, “You’ve got a lot of movement of material: you’ve got to grow it somewhere, you’ve got to use quite a lot of land to grow it, you’ve got to move it [left over wastes], you’ve got to store it, you’ve got to process it, you’ve then got to store the biochar before it goes onto the field. And if you’re talking about very large volumes, you’ve got to store it somewhere.”

In biochar manufacture and use there is a temporal delay: Shackley says often the feedstock waste from agriculture will come from the end of a harvest, but the most useful time to use it would likely be the following spring or summer. Logistics are a huge part of the process but those details are often glossed over.

Only loosely mentioned is a third problem: no one is entirely certain of the optimum composition of biochar for maximum temporal carbon sequestration. An article about biochar on MNN mentions in passing, “Plowing biochar into soil sequesters the carbon for a long time -- biochar fields have been found in South America dating back thousands of years and still full of their carbon solids.” A long time sure, but it depends on what it’s made of.** Scientists may be able to test terra preta to see what it’s been made of in the past, but other materials will be used to create modern biochar.

So why not only make biochar from certain specific materials? Simplistically: Soil contains bacteria and mineral nutrients that help plants grow. Biochar contains minerals as well that are beneficial to plant growth, which makes it beneficial as a fertilizer. Different biochar compositions could provide optimum minerals depending on the soil composition. It’s common sense that in order to be sustainable, biochar be composed of native organic materials. So, wherever it’s used its make up will vary.

Biochar can be made of almost any material and some materials, according to Dr. Saran Sohi, a soil specialist at the UK Biochar Research Institute, are more stable than others. Stability determines how long carbon will be trapped (sequestered) in the soil. There’s not yet been enough research to determine how long certain materials will sequester carbon.

“When you pyrolyze material you end up with a complex substance. And some of that is volatile,” explains Shackley. Any biochar used as an agricultural fertilizer (carbon sink) will have to be stable for well over 100 years, “Ideally we want to keep 75-80% of carbon in a stable form for hundreds of years. If it all comes out as CO2 after 100 years, in my view, it isn’t worth it.... Because if we haven’t solved the problem, and it all comes out again in 100 years time ...you could get billions of tonnes of carbon dioxide back in the atmosphere and we might be having a severe climate crisis and it could be disastrous.”

Forth, the market model is uncertain on several levels: Sohi says that more research must be done on biochar composition so that the benefits to farmers (i.e. increased crop yield) can be clearly enumerated. Until then a market price for biochar as a fertilizer will be hard to pin down. It will also be difficult to displace traditional chemical fertilizers with this “natural” alternative, where the added yields are certain. Any market in developing countries where charcoal is used as a fuel (even as a low-carbon alternative) and an agricultural input must be heavily regulated: in order that charcoal remains cheap enough to be used as a low cost agricultural input, to prevent people trading the biochar at profit to be used as fertilizer (rather then fuel too), then from turning to another fuel that might degrade the environment.

After years of colossal f-ups, the development community has to come to an agreement that aid must be nuanced-- that is, designed specific to the environment in which it’s implemented. The financial crisis(es) have shown us that we need heavy market regulation, not just of financial markets but commodities as well. In order to address climate change we need to use all of the technology at our disposal, which includes biochar. But unless we take our time, and correctly implement its use, biochar could do more harm than good. The US’s biochar bill might be something to be weary of. Shackley points out that such a bill will drive more investment into research and make certain that regulators ask the right questions about safety and benefits. On the other hand, history has shown that governments dolling out money must be monitored to make certain processes are safe. More research must be done on biochar, its use should not be rushed into, and the market must be heavily regulated.



* Dr. Paulo dos Santos, SOAS.
**For example manure, palm tree litter are more volatile.