Monday, 27 October 2008

Cheaper Biofuel

Biofuels have had a bad rap recently over  the concerns over food prices, and rightly so.

However, not all biofuels are created equal. The "easy" biofuels such as those from sugarcane sugar*, seed oils or corn starches impact food prices because they use the portion of the crop that would otherwise be used in food production. No surprise, because food is our fuel, so it is pretty obvious that this aspect would be the easiest or only part of a plant to be usable as fuel for machines.

However, this ignores the woody matter: leaves, stalks, bark. Wood is made of lignin, which, to many peoples' surprise, is in fact a very stable, complex polymer of glucose. Yep, it is, under all that, sugar. Because it is a very stable polymer, our digestive tract cannot extract meaningful energy from it. Bacteria can. Anyone on a high fibre diet will know that bacteria can convert woody material, the fibre, into methane gas...

Mankind has harnessed bacteria to break down lignin, but it has needed high temperatures and has not been highly efficient. 

However, the guys at Cobalt Biofuels appear to have devised a process to reduce the cost (and by that it means energy and waste) of biofuel production using the woody waste matter. Not only have they reduced the cost, but they have produced Butanol, which has a higher energy density, is more compatible with existing infrastructure and is far easier to handle than the more common biofuel output, ethanol. Ethanol is a bit scary, actually, as it is a colourless, odourless and transparent liquid. It looks, smells and, who knows, tastes like water - drink it and you will be unlikely to live long enough to discuss the merits of its complex lingering finish.

In all of this there remains, for me, a nagging doubt. If the process is developed, biomass may be removed from the cycle, even if it is usually burnt on site. To  me that suggests a change in the cultivation process, an impact. Such changes need to be understood and all the implications thought through - e.g. the need for more fertilisers etc. If biomass is removed entirely and not used elsewhere (this I doubt!) then biomass waste for biofuel production should have little impact. Alas, a cheaper process could mean more land turned over to switchgrass or other biomass crops, thus reducing potential food yields.

One good thing about biofuels is it has shown how Government meddling can create problems that would never have occurred. Governments have been subsidising biofuel crop production and up till now this has meant diverting food production into fuel production. We have seen how this can destabilise food prices, as it is an unnatural distortion. 

If biofuels are to make any sense, it would be produced from land otherwise not used for food production, not used for anything in particular, in fact. Biofuels can also be used first in places where their cleaner, less carcinogenic products of combustion may be at a premium, e.g. in domestic generators, food delivery vehicles and taxis**. In such cases I would wish it to just power a backup generator in a series hybrid, but then who expects common sense from ricebowlers who wish to keep their job at Toyota or GM designing cam lift profiles, eh?

* the distinction is important here.
** why we permit cities to be polluted by diesel vehicles is a mystery to me given all the other wibble going around. Taxis can easily be electric or plug-in series hybrid and B100 biodiesel produces hardly any particulates (soot), no sulphur and a far better balance of the other gasses.


Kit said...

Slight catch to this cunning plan and it is our friend unintended consequences.
Just because we cannot eat "woody material" doesn't mean it has no uses. A US research program using husks and straw was canceled because of topsoil depletion. The woody matter would normally be dug back into the ground. Farms taking part in the project were losing 1cm of topsoil each year.

Roger Thornhill said...


Exactly, which is why I flagged my concern if the woody material is normally left on the fields or burnt and not removed.