Biofuels get drafted

According to the Defence Energy Support Center (DESC), which is responsible for managing all US defence-related energy supplies, the US military consumed 132.5 million barrels of petroleum-based fuel in 2007 at a cost of $12.61 billion. Now while this represents less than 2% of total US fuel consumption, it does equate to the total fuel consumption of a modern European country such as Portugal or Sweden.

Given this massive fuel use, together with the importance of ensuring that US forces have access to a secure supply of fuel, it’s not surprising that the US military is beginning to turn its attention towards biofuels.

But there is a stumbling-block. For although some sections of the military already use ethanol and biodiesel blends in their ground vehicles, current biofuels tend to be unsuitable for many military applications, such as for use as a jet fuel.

This is because current biofuels often just don’t have the right set of properties required by military vehicles. For example, ethanol and biodiesel possess an energy density that is around 25% lower than the kerosene-based jet fuel used in fighter planes, known as JP-8. In addition, unlike ethanol and biodiesel, JP-8 is able to perform at temperatures as low as -50°C, which planes can experience at high altitudes.

So for biofuels to make a greater contribution to the US military’s fuel supplies, the military will need to develop its own. This is what the US Defence Advanced Research Projects Agency (DARPA) is now doing through its Biofuels program.

Launched in 2006, the main aim of this programme is to fund the development of an affordable and highly efficient process for converting plant oils, such as soybean oil, into a substitute for JP-8. To this end, in July 2006, DARPA called for the submission of research proposals.

DARPA was looking for a process that could achieve a conversion efficiency of 60%, meaning that 60% of the energy content of the plant oil must end up in the JP-8, with the potential to extend this efficiency to 90%. At the end of the project, the research partners must deliver 100 litres of the JP-8 substitute for testing.

In November 2007, DARPA extended the scope of its call for research proposals to processes that could produce substitute JP-8 from cellulosic materials and algae.

One of the organisations that subsequently received funding under this program is UOP, the energy technology subsidiary of the US industrial conglomerate Honeywell. In June 2007, it received almost $7 million from DARPA to develop a JP-8 substitute based on its ‘green diesel’ production technology (see Biofuels take flight).

A joint group from the University of North Dakota and the Energy and Environmental Research Center received funding to develop two new processes for producing a JP-8 substitute, one based on thermal cracking and one based on catalytic cracking. While General Electric Global Research used its funding to develop an optimised catalytic process based on hydrotreatment and isomerisation.

As a result, DARPA has received a number of fuel samples that have met all its key first-level specifications.

But the potential advantages of biofuels for the military go beyond cost and environmental concerns. For biofuels offer the US military the potential to produce its own fuel while out on manoeuvres, rather than having to go through the difficulty of taking its entire fuel supply with it through often hazardous and dangerous territory.

To this end, at the beginning of October 2008, the DESC announced that, together with the US Army, it was testing seven new biomass units that are able to turn biodegradable waste into fuel. Designed by the US biofuel developer Bell Bio-Energy, these units employ a suite of genetically-modified bacteria that can break down organic waste material and transform it into diesel and a range of useful by-products, including potting soil.

‘These units will be able to use mess hall and latrine waste as feedstock and the fuel produced from this waste can then be used in back-up generators or other diesel equipment,’ a DESC spokesperson told BioFPR. ‘The idea is to reduce the amount of fuel delivered to Forward Operating Bases and keep the quality diesel/jet fuel for tactical vehicles.’

So, to paraphrase Napoleon, in the future armies will not only march on their stomachs, they’ll also be able to drive and maybe even fly on the leftovers.

The views represented here are solely those of the author and do not necessarily represent those of John Wiley and Sons, Ltd. or of the SCI.