The Pentagon – which gave the world the gas-guzzling, 68 ton M1 Abrams tank, which does just over half a mile to the gallon – is leading the charge. But Britain's own Ministry of Defence, responsible for 70 per cent of all the government's carbon dioxide emissions, is not far behind. And the prestigious Royal United Services Institute is to hold a conference this year on what other Nato countries are doing.
The US military – the country's largest single energy consumer – has embarked on a drive to save fuel, and thus lives. Half of its wartime casualties are sustained by convoys, which are mostly carrying fuel and are a favoured target for enemies. It estimates that every 1 per cent of fuel saved means 6,444 soldiers do not have to travel in a vulnerable convoy.
One simple innovation – insulating tents in Iraq and Afghanistan with a layer of hard foam, reducing the need to heat and cool them – has saved 100,000 gallons of fuel a day. The Pentagon aims to get a quarter of its energy from renewable sources by 2025. It is to buy 4,000 electric cars (the world's largest single order) for use on its bases, and is developing hybrid armoured vehicles for the battlefield.
It has saved fuel by cutting the weight of aircraft – removing floor mats, redundant tools, loading thick manuals on to laptops, and using lighter paint – and within seven years plans to fly them on a 50/50 blend of ordinary fuel and biofuel, probably made from algae.
Five weeksago the MoD identified "reducing dependency on fossil fuels" as a main object of its research. It has already reduced carbon dioxide emissions from its buildings by 10 per cent this decade. All RAF planes, apart from the Battle of Britain Memorial flight and a few training aircraft, have been certified to fly entirely on biofuels, when they are available, and researchers are looking into solar-powered unmanned attack aircraft.
Scientists hope that the massive spending power of the military will spin off environmental technologies into civilian life, as jet engines, microchips, and global positioning systems did in the past. "We can be a test bed for a lot of things that normally would not seem to make powerful economic sense," said the US Assistant Army Secretary, Keith Eastin.Reuse content