The tooth to tail ratio describes the amount of support available to sustain combat soldiers. The equation used to be straightforward: more support (tail) makes for a more effective combat force (teeth). DARPA - the Defense Advanced Research Projects Agency - aims to stand the equation on its head, in part by stripping energy-related support requirements to the lowest possible levels. One way to do that is to reduce the military's dependence on conventional batteries, which can weigh up to 125 pounds per team for a one-day radio recon exercise. In effect, DARPA is approaching the tooth to tail ratio as a standard for reducing the U.S. military's carbon bootprint, rather than adding to it.
DARPA's robust power program is just one piece of the portable power puzzle. U.S. military fuel cell research has been covering several other more sustainable configurations, including photovoltaic. Genetically engineered viruses and silicon are pushing the envelope for lithium batteries, and a green makeover is in sight for old lead-acid technology, too.
The military concept of sustainability is as old as war itself. It's a matter of life or death.
As the U.S. military relies on ever more power-hungry gear to support its teeth, it's going to need a far more efficient, portable, and logistically sustainable power supply than conventional fuels and batteries can offer. Just one statistic reveals the urgent need to change: according to DARPA, about 70% of the trucks in a typical military convoy are used for transporting petroleum fuels.
As for the rest of us, despite the kicking and screaming from global warming deniers and the "clean coal" shills, alternative energy is no field exercise. Survival is the stakes. Whether we like it or not, we live in a mechano-electronic world that drags a heavy tail, and it's only going to get heavier. Our ability to sustain that world depends entirely on the new kinds of energy we develop to power it.