From the official website of the U.S.M.C.  

Marines are modern-day Spartans – our ethos demands that we change the way we think about energy as we train, equip, and lead our expeditionary force

Marines in Afghanistan use about 200,000 gallons of fuel a day to power our warfighting capabilities and sustain our forces. While we have proven lethal fighting in rugged environments for nearly a decade now, we've dramatically increased our energy consumption. Because of our thirst for liquid fuel, we're not as light and agile as we once were, putting both our Marines and our expeditionary capabilities at risk.

The Marine Corps Expeditionary Energy Strategy, spanning Bases to Battlefield, centers on changing the way we think about energy – that our warrior ethos equates the efficient use of energy and water resources with increased combat effectiveness.

Our priority is to save lives by reducing the number of Marines at risk on the road hauling fuel and water.

Our objective is to allow Marines to travel lighter -with less -and move faster by reducing the size and amount of equipment and dependence of bulk supplies.

The key elements for success are to aggressively pursue innovative solutions to reduce energy demand in our platforms and systems, to increase our self-sufficiency in our sustainment, and to reduce our expeditionary foot print on the battlefield.

Transforming the way we use energy is essential to rebalance our Corps and prepare it for the future. The strategy calls for, by 2025, Marine Expeditionary Forces capable of maneuvering from the sea and sustaining C4I and life support systems in place; the only liquid fuel needed will be for mobility systems, which will be more energy efficient than systems are today.To this end, by 2025 we will reduce by 50 percent our battlefield requirement for energy. By 2020 50 percent of our bases and stations will be net-zero energy consumers.

Source:   USMC Expeditionary Energy