The private sector isn't alone in its pursuit of mean-and-green, energy-conscious technologies. All branches of the U.S. military have thrown their hats into the race.
For one thing, our dependence on foreign oil has been acknowledged by the military as a strategic disadvantage. Some 80 percent of the military's energy consumption comes from oil products, according to a 2011 report on green initiatives in the armed forces by the Pew Charitable Trusts.
In other words, the military can hardly fly a jet, propel a ship or move a troop without guzzling gas. The sooner our armed services quit their 375,000-barrel-a-day binges, goes the argument, the sooner they can free themselves from the crap-shoot of oil market fluctuations and perilous entanglements with hostile regimes.
"Militaries that fail to innovate lose strategic advantage. Nations that fail to innovate lose economic edge. Clean energy innovation is an essential strategy for making the United States and its service men and women safer, stronger and more successful," wrote the authors of the Pew report.
Of course, the military is also under orders from Congress and from their commander-in-chief, President Barack Obama, a fact not lost on critics of the administration's environmental policies.
Regardless, the military is continuing to explore new ways - by land, by sea and by air - to wean itself off the oily teat of fossil fuels. Here are 10 examples of technologies and habits employed by the U.S. military that officials hope will turn out to be both environmentally sound and strategically advantageous in the long run.
1. On-Base Electric Vehicles
The military is beginning to make use of small electric cars on base. These are made from recycled plastic and can reach speeds of 25 mph. The military will be slower in rolling out "green" combat vehicles, since performance is paramount to troops' safety.
2. Soldier Conformable Rechargeable Batteries (SCRB)
Thin enough to conform to soldiers’ protective chest plates, these "batteries" (not pictured) actually use a small 25-watt fuel cell and can support a 72-hour mission before recharging is necessary, according to the Pew report.
3. Rucksack Enhanced Portable Power System (REPPS)
This backpack solar power system can be unrolled and used to recharge batteries in five to six hours or act as a continuous power source.
4. Solar Power Shades
This solar shade helps to cool the tent below while 72 panels absorb sunlight to produce two kilowatts of power a day in Djibouti.
A microgrid is a closed system that may or may not be linked to the commercial power grid and can combine a number of separate energy sources - "smart" generators that link with one another to intelligently manage the power supply. This one, a 1-megawatt microgrid, went through seven training rotations at Fort Irwin, Calif. from August 2010 to March 2011.
6. FED - A Greener Humvee
The Fuel Efficient Ground Vehicle Demonstrator, or FED, would have the same capabilities as the M1114 Humvee but with about 70 percent greater fuel efficiency. Displayed here in the Pentagon courtyard for an Energy & Sustainability Technology Fair, a solar-collection panel can be seen on the rear hatch of the vehicle.
7. Hybrid-Electric Ships
The amphibious assault ship USS Makin Island is the only Navy ship with a hybrid-electric propulsion system, but the goal is to switch more of the fleet over to "green" engines.
8. The "Great Green Fleet"
The Navy hopes this summer to demonstrate a "green" carrier strike group, much like the one pictured. It will feature a nuclear carrier, as well as surface ships and aircraft powered by biofuel. The Navy's goal is to demonstrate the "Green Strike Group" in local operations in 2012 and then sail it by 2016.
9. Adaptive Versatile Engine Technology (ADVENT)
This new breed of engine, part of the Versatile Affordable Advanced Turbine Engine program (a joint program under the military and NASA), is designed to switch intelligently between two modes: one for high performance, the other for fuel efficiency. Think of it like the hybrid engine in your car - when you're idling or cruising at low speed, the gas engine turns off, but when you put the pedal to the metal, the combustion engine kicks in.
10. Biofuel-Powered Aircraft
The Navy and Air Force have already demonstrated that they can fly fighter jets on a 50/50 mix of biofuel and standard jet fuel. The Navy's F/A-18 Super Hornet flew on a blend derived from camelina seeds. The jet (pictured above) was dubbed the "Green Hornet." Another familiar sight, the Blue Angels, have also flown on a biofuel blend (pictured below).