This column was published in the Waikato Times on 20 January
A couple of months ago a young company called Carbonscape opened a new plant in Marlborough. It makes charcoal from wood waste, hardly an exciting matter one might think. But beyond its traditional use as a fuel, charcoal may hold enormous potential for a sustainable future, for several reasons.
Soil fertility is one. Charcoal added by humans to the soil in pre-European times in the Amazon region has produced a much higher level of fertility than normal in the relatively poor soils of the region. Modern experiments indicate that at least some soils benefit greatly from having porous charcoal added to them. Our neighbour Australia is finding this in soils which are lower in carbon content than optimal. The biochar, as it is called, seems to act as a catalyst to increase soil fertility. Less fertiliser is required. Microbial and fungal activity is increased. Water retention is improved. Leaching of nitrate and phosphate to waterways is reduced. Crop growth is greater, sometimes considerably so. And the biochar itself lasts for many centuries, being a very stable form of carbon.
It has a second beneficial effect. Biochar incorporated into the soil becomes a carbon sink and lowers greenhouse gas levels. The CO2 used by the growing tree is not returned to the atmosphere by decay or burning. Instead biochar stores it in the soil where it remains sequestered for many centuries. Additionally, the soils in which it is incorporated appear to be giving off less CO2than normal and much reduced levels of nitrous oxide. On a large scale biochar thus appears to have enormous potential in fighting global warming by removing CO2from the atmosphere. Well-known Australian scientist Tim Flannery has become an enthusiastic advocate: “It will change our world forever, and very much for the better.”
A third benefit lies in the by-products of the process of charcoal-making. They include bio-oils which can be refined for transport use and syngas which can be used to power the charcoal-making process itself.
To return to Carbonscape. The company is breaking new ground in the way it makes its charcoal, using a world-first industrial mocrowaving process, not the traditional method of burning under restricted air availability. Microwaving is expected to use less energy, and the conversion rate of the raw material to charcoal is at the top end of the range by comparison with other methods.
The idea came from the experience of Chris Turney, one of the directors of Carbonscape. Years ago, as a teenager, he set out to microwave a potato and, not knowing how, set the timer to 40 minutes. The result was a dead microwave and a glowing black lump where the potato had been. The teenager has become a geologist, a professor at Exeter University and successful author of popular science books on the past, particularly past climates. (I recently reviewed his latest book for Hot Topic here.) Years later that charred potato opened up a line of thought for him: could microwaving plant material help get the amount of greenhouse gases in the atmosphere down?
It is early days in the company’s life, and so far their activity is limited. They have a strategic relationship with Lincoln University for research into biochar effects on NZ soils. They are experimenting with feedstocks from a variety of waste streams, not only wood. They are also experimenting on perhaps being able to produce high-value biochemicals as by-products. International links are being established. Work has begun on a second larger version of their plant, which will mean continuous production.
Carbonscape is a welcome addition to companies in New Zealand developing new technologies for a sustainable economy. Two of its directors are also directors of Aquaflow, another Marlborough company which has become a world-first group in creating biofuel from wild algae grown in waste water. These and others in the country are small beginnings, and no one can guarantee what may come from them, but their technological enterprise is worth a great deal for the sustainable future we desperately need.
Postscript: Since writing the column I heard from someone attending a recent talk in Cornwall by The Revenge of Gaia author James Lovelock reporting that he spoke approvingly of the possibility of biochar providing the kind of massive carbon sequestration we need – even if he went on typically to doubt that the world would get its act together sufficiently to put it into operation.