According to US studies fuel alternatives to keep army on the move, the US military is researching fuel alternatives, because the cost of getting fuel to the battlefield is astronomical:
A gallon of modified jet fuel, which is used in tanks as well as aircraft, costs only 84 cents when bought wholesale from multinational oil companies such as Shell and ExxonMobil.By the time the cost of transporting the fuel to the battlefield is added, that sum can rise to hundreds of dollars per gallon.
The US army says that for the campaign in Afghanistan, where there are no reliable or significant sources of fuel, the army depends on fuel flown in by helicopter from ships in the Indian Ocean. The cost per gallon: about $600 ( €557, £381).
The US army estimates it costs about $150 per gallon for fuel used in Iraq. The fuel comes from 23 US military dumps scattered across the Middle East, a number that was doubled in preparation for the current conflict.
They’re developing prototype hybrid vehicles, because, “Much of the US army’s current logistics support system exists for the sole purpose of moving fuel around.”