Credit and Criticism for Biochar

Check out the on-going debate in the Guardian about Biochar, which was sparked from Monbiot’s article (see posts further down).

In particular see Prof. Michael Hayes’ (CCSN Advisory Panel) response below.

Some aspects of George Monbiot’s article (Woodchips with everything. It’s the Atkins plan of the low-carbon world, 24 March) have merit. I would prefer, however, to be guided by the experts it refers to. To grow biomass merely to provide biochar may well not be a viable option. To grow it as a feedstock for second-generation biorefining to yield products such as furfural, hydroxymethylfurfural, levulinic acid and formic acid has merit. These chemicals can give rise to a green chemistry industry through which we can make most of the products now sourced in petroleum. We call this a “renaissance of the carbohydrate economy”.

The value does not end here. The biorefinery residuals include lignin components and polymeric materials which, when pyrolysed, can produce syngas, bio-oil, and biochar. It is not necessary to dwell here on the value of syngas. The bio-oil can be upgraded to a diesel additive, and biochar is considered to have conferred enormous fertility to the Amazon region’s terra preta soils.

We have recent experience in these areas. Our biochars have produced an amazing effect on the germination of maize seeds, and the growth of the emergent plants. We have observed a huge proliferation of fungal mycelia associated with the roots in the char-amended soil, and these may influence plant growth. However, we believe the early germination results from a hormonal effect from bio-oil products sorbed by the biochar.

To us so-called organic wastes are assets. We regret that consideration is given to incineration of these. We have calculated that the biorefining of Irish organic wastes could provide up to half of the fuel additives scheduled for 2010, and to grow energy crops to provide the remaining additives would need an insignificant amount of the nation’s agricultural land. In addition we could expect huge benefits from the syngas, bio-oil, and biochar products.

Professor Michael Hayes
University of Limerick, Ireland