This year’s drought in the US – said to be the worst for 50 years – has, according to Marie Brill, senior policy analyst with ActionAid, an international development charity, re-ignited the food versus fuel debate, bringing the merits of biofuels once again to the political agenda.
But despite the controversy, Environmental Protection Agency (EPA) regulators have announced that diesel fuel refiners must blend 1.28 billion US gallons (6.2 billion litres) of biodiesel into the country’s overall diesel supply in 2013 – a 28% increase on this year’s requirement.
This year’s drought in the US has re-ignited the food versus fuel debate, bringing the merits of biofuels once again to the political agenda
Biodiesel is more costly to produce than regular ultra-low sulphur diesel (ULSD), to the extent that American Trucking Associations have estimated an increased cost for diesel consumers of around US$476m. The estimate has to be approximate because of the varying blend ‘strengths’ of biofuel in the product supplied in bulk to truck and bus users and that sold at public filling stations.
At some truckstops there are now three or four diesel pumps, typically dispensing ULSD, B10, B20 or B100 blended fuel, those numbers indicating the percentage bio content. Vehicle operators are constrained in the blends they can use – not just by cost, but also by conditions laid down by the engine manufacturers. The fuel systems of most truck and bus diesel engines built in the last five years or so, meeting EPA 2007 or 2010 emission regulations, will tolerate B100 biodiesel without damage to seals or otherwise jeopardising engine durability. But many older engines are subject to manufacturer warnings about reliability risks, or the terms of maintenance contracts being invalidated, if diesel with more than 10 or 20% bio content is used.
As the percentage of total US diesel fuel with bio content is increased, it is likely that, at some point, demand for ULSD – driven by its lower price, the need for its use in older engines and by availability – will outstrip supply. The only truck and bus operators welcoming biodiesel are the environmentally-minded, including those keen to project a green image to their existing and potential customers.
As the percentage of total US diesel fuel with bio content is increased, it is likely that, at some point, demand for ULSD will outstrip supply
The lower calorific value of biodiesel – up to 9% less than ULSD in the case of B100 – can be seen as adding insult to injury from a cost aspect: poorer consumption and a higher cost per gallon/litre. Elsewhere in the world, biofuel prices are government subsidised. But there is no such federal incentive in the US. And from an emissions point of view, although biofuels contribute to a net reduction in global greenhouse gases, while also cutting diesel particulates, they tend to increase NOx (oxides of nitrogen) emissions.
An issue which, surprisingly, appears not yet to have been addressed is engine certification to EPA 2010 standards when running on different biodiesel blends. In North America, as in Europe, official emission level certifying tests are carried out only using a standard ULSD fuel with no bio content.
The opinions expressed here are those of the author and do not necessarily reflect the positions of Automotive World Ltd.
Alan Bunting has a background in engineering, and has been writing on commercial vehicle and powertrain related topics since the 1960s. He has been an Automotive World contributor since 1996.
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