1) In the American bases in Iraq and Afghanistan, about 40% of fuel is used to run electricity generators. Energy consumption has been reduced by coating military tents with a thick layer of commercial insulation foam, the kind used for cavity walls in homes, covered with sealant to protect it from ultraviolet light. This treatment halves the energy needed for air-conditioning and pays for itself within three to six months, depending on the price of fuel. If the various generators on a base are connected in a "smart grid" system, which optimizes their operation and distributes power to priority areas, such as communication equipments, a further 20% saving is possible.
2) A battalion of about 500 men typically produces about a ton of waste every day. A machine called Tactical Garbage to Energy Refinery (TGER) heats solid waste to produce syngas (synthetic gas, a mixture of carbon monoxide and hydrogen), ferments food slops to produce alcohol, and chemically processes the two to make biodiesel that powers a generator. TGER produces as much as 64 kilowatts of power - enough to run the command post of a battalion.
3) By 2016 the American air force seeks to use a 50:50 blend of synthetic and ordinary jet fuel for half of its aviation requirements.
4) The American navy has tested a biofuel made from the camelina plant in its F-18 Hornet jet. Later the biofuels will be tested for ship turbines. It is also installing stern flaps on its amphibious vehicles that can reduce fuel use by 2-3% and developing better coatings to prevent the growth of algae and barnacles on hulls that cause drag and increase fuel consumption. In October 2009, the USS Makin Island, an amphibious assault ship, was the first of 12 hybrid-powered ships to take to the water. It saved nearly $2 million in fuel costs on its maiden voyage alone.
Source: "Greenery on the march." The Economist, December 12th 2009.