Biochar 1: Background


“Biochar is not the miracle cure-for-all that some advocates claim. However, we still consider it a critical technology to be researched for poor countries.

Authors: Jakke Mäkelä, Kalle Pietilä, and Viv Collins. [Originally published in

The production of biochar is being advertised as one of the most important low-cost high-impact technologies. See, for example, Open Source Ecology. The premise is relatively simple: biomaterial such as wood (or, ideally, wood waste) is heated in a kiln which does not let in oxygen.

The wood then breaks down into three components, with ratios depending on the temperature: charcoal, oils, and volatile gases. The gases can be fed into the heater, meaning that the process can keep itself running once it has been started. The oils can be used as clean fuel sources. Overall, the process can thus enable far more energy production than is needed to run it.

Most of the carbon is thus sequestered into the charcoal, with little carbon dioxide emitted. The CO2 that was taken up by the plants is thus fixed in the charcoal, which can for example be buried, never releasing the CO2 into the atmosphere. This can thus be a low-tech solution for carbon sequestration.

The “bio” part of the term comes from the possibility of combining the charcoal with nitrogen-based fertilizers, resulting in a very effective yet stable fertilizer. The theory is that the charcoal binds the fertilizer, preventing it from being leached too quickly by rain. This benefit has so far not been proven adequately, but at worst the charcoal should be a neutral element in the soil even if it does not give additional benefit.

We are doubtful of some of the most wide-eyed claims being made about it, and there are very strong skeptics of the process, especially at larger scales (see e.g. Climate Justice Now). The downsides are fairly obvious: the charcoal production will release particulate pollutants as well as possibly other toxins, unless it is done very efficiently. Also, at extremely large volumes the process would stop making ecological sense, as large plantations would have to be grown just for this purpose. At some size scale, the process would become ecologically completely counterproductive.

However, at smaller size scales the technology could have local health benefits, by providing a cleaner-burning fuel. The burning of unclean wood products in poorly designed kilns produces high indoor pollution levels and can be a health risk (FAO; this article however considers better stove design to be the key, and remains neutral about any relative health benefits given by charcoal).  Others (World Bank) consider that moving to cleaner and inexpensive charcoal would have clear health benefits.

Biochar is not the miracle cure-for-all that some advocates claim. However, we still consider it a critical technology to be researched for poor countries.  Whatever the actual value of the technology is, it would be pointless to allow spurious IPR to slow the progress.

Figure 1. Basics of biochar. Source:


The EFA article above describes a combination of a kiln that carbonizes agricultural waste into biochar, and an energy efficient briquetting machine that makes charcoal briquettes that can burn in ordinary stoves. Some of the biochar is used to make fertilizer and some to make briquettes.

For more on biochar, see International Biochar Initiative.  The current state of the art is described in the IBI production web page. The size scales can vary by a huge amount, from industrial-scale installations producing 1 ton per hour to small installations producing 500 kg a day or less.

The technology is described in the IBI technology web pages. The most critical general comment is this:  “But biochar technology is more than just the equipment needed to produce biochar. Biochar technology necessarily includes entire integrated systems that can contain various components that may or may not be part of any particular system.”

This is something to worry about. From the humanitarian IPR point of view, there is one crucial question: could spurious IPR be used to block development of large-scale biochar burning? In particular, could it block development of such technologies aimed at developing countries?

The IBI technology page mentions five specific goals for future R&D:

  1. Continuous feed pyrolyzers to improve energy efficiency and reduce pollution emissions associated with batch kilns.
  2. Exothermic operation without air infiltration to improve energy efficiency and biochar yields.
  3. Recovery of co-products to reduce pollution emissions and improve process economics.
  4. Control of operating conditions to improve biochar properties and allow changes in co-product yields.
  5. Feedstock flexibility allowing both woody and herbaceous biomass (like crop residues or grasses) to be converted to biochar.

It is #4 that we should be most worried about. There should be easy work-arounds and multiple technologies for the other areas (in which patents can be found just by searching for “biochar”). It is in practice not possible to block the development of new kiln types because alternative designs can always be used. A single troll patent for #4 could, however, stop the whole system. We will be analyzing this area in future postings.