NOTE: This is the first of a three-part series.

In the arid lands of the Mojave Desert, Marine regimental commander Jim Caley traveled alongside a 24-mile stretch of road and saw trucks, tanks and armored tracked vehicles all idling in the heat and wasting enormous amounts of expensive fuel.

Caley had already led forces in Iraq, and at the time was charged with seven battalions comprising 7,000 Marines. But this was a new and different challenge. Overseeing a major spring 2013 training exercise at the Marine Corps' Twentynine Palms base in southern California, he was struck by how little he knew about how America's war-fighting machine used energy.

"No targets prosecuted, no miles to the gallon, no combat benefit being delivered," Caley, a Marine colonel, says of the scene. "At the time, I had no system to understand what was going on, and what was occurring, and how much further I could go on the same fuel."

The Department of Defense is the single biggest user of energy in the U.S. its energy bill in 2013 was $18.9 billion and Caley now plays a central role in trying to ensure that just one of its branches, the Marine Corps, uses that power in the optimal way. The implications for the military are vast. For instance, the Marines alone have estimated that they could save $26 million per year through a 10 percent energy reduction at their installations and bases, to say nothing of Marine field operations, which used an estimated 1.5 million barrels of fuel in 2014.

But most striking is how these changes are coming about. As head of the Marines Corps' five-year-old Expeditionary Energy Office, Caley is tapping into one of the hottest trends in academic energy research: looking to use psychology and the behavioral sciences to find ways of saving energy by changing people their habits, routines, practices and preconceptions.

"The opportunities that we see on the behavioral side of the house are phenomenal," Caley explained during a recent interview in his Pentagon office. "And they're frankly less expensive than us trying to buy new equipment."

Through behavioral changes alone tweaking the ways that Marines drive their vehicles, power their outposts, handle their equipment Caley thinks he can increase their overall battlefield range by as much as five days, a change that would provide immense tactical benefit by cutting down on refueling requirements (and the logistical hurdles and vulnerabilities associated with them). If he succeeds, the Marines would stand at the forefront of an energy revolution that may someday rival wind or solar in importance: one focused not on changing our technologies or devices, but on changing us. And its applications would touch every corner of our society, from how we behave in our homes to how we drive our cars.

Any change to how the military uses energy has momentous implications simply because it uses so much of it roughly the same amount of power annually as the state of West Virginia. But the behavioral revolution in energy is also highly significant in the civilian sector, where truly Pentagon-sized energy gains could be reaped just by tweaking little behaviors. For instance, here are some published estimates of possible energy savings from behavioral changes. These shouldn't be taken as exact, but rather as ballpark figures:

One 2009 study suggested that American households which account for around 40 percent of U.S. carbon emissions could achieve a 20 percent emissions reduction by changing which household appliances and objects they use, and how they use them. That's greater than the total emissions of the country of France.

Read more:
The next energy revolution won't be in wind or solar but in human behavior