When experts get confused, what hope is there for the rest of us in assessing the potential of biofuels for transport? In a recent publication (of which more later), the Institution of Chemical Engineers (IChemE) points out that "In a very short time environmental lobbyists had moved from being supportive of biofuels to a position where biofuels were not to be tolerated at any price."
When it comes to this change of heart, the IChemE, which should know a thing or two about large chemical engineering plants, pinpoints a paper by PJ Crutzen and others in the journal Atmospheric Chemistry and Physics as a turning point. The paper's title summed up the issue: "N2O release from agro-biofuel production negates global warming reduction by replacing fossil fuels".
http://www.atmos-chem-phys.net/8/389/2008/acp-8-389-2008.pdf
Yet more bad PR came for biofuels in the May–June 2009 issue of Agronomy Journal, which has an article warning that the crop residues that some people see as feedstocks for biofuels also play an important part in maintaining soil quality. Make biofuels out of the straw and other stuff that usually gets ploughed back into the ground and you run the risk of reducing soil fertility and subsequent crop yields.
http://www.newswise.com/p/articles/view/552980/
Around the same time as this warning arrived, researchers at the University of Twente in The Netherlands reported on their studies of bioenergy and its 'water footprint' – "the total annual volume of fresh water used to produce goods and services for consumption". In their paper, in the Proceedings of the National Academy of Sciences, the researchers warn that the water footprint of bioenergy "is large when compared to other forms of energy. In general, it is more efficient to use total biomass, including stems and leaves, to generate electricity than to produce a biofuel."
http://www.pnas.org/content/early/2009/06/03/0812619106
This torrent of confusing stories prompted the IChemE's Energy Conversion Technology subject group to commission a "Biofuels compendium" in the hope that it "may assist in navigating around this most complex of subjects and provide a mini reference at the same time".
http://cms.icheme.org/mainwebsite/general-barafc3d75d.aspx?map=bd6a5b23f4897056bbccae9b030a96d7
By bringing together data from credible sources, the IChemE's report highlights aspects of biofuels that don't show up in the breathless output of the advocates and their critics. For example, one small detail in the review came as a bit of a surprise. In the discussion of well-to-wheels (WTW) greenhouse gas (GHG) performance we read that "biofuels from wood-sourced biomass have very similar WTW GHG performance in conventional powertrains and are very competitive with hydrogen-based technologies and at a significantly lower cost".
In general it seems that hydrogen is less than 'green'. "Several fuels give as good or better performance on a well-to-wheel basis than hydrogen without the high on-costs of infrastructure associated with the use of hydrogen."
A further conclusion is that "biomethane made from liquid manure actually achieves a negative well-to-wheel greenhouse gas contribution".
The document does not try to offer any conclusions on the wisdom or otherwise, of biofuels. It can't hope to in a 40-page booklet. But one thing is pretty obvious: any biofuel economy is going to be very complicated, so much so that today's oil industry looks like child's play. And any complex system is likely to have all sorts of extra costs.
Categories: Commentary ,
24 February 2010
Comments
All comments
You need to be registered with the IET to leave a comment. Please log in or register as a new user.