One carefree summer day in California, a few college students went for a joy ride. It was the perfect day to don the shades, roll down the windows, and crank up the tunes.

But then someone noticed all the bumps in the road. These were engineering students from the Massachusetts Institute of Technology, and the group got to thinking: Isn't there energy in that?

So they rigged up a bunch of small sensors. They strapped them onto rental cars and took them for a spin. Sure enough, they found that just by bouncing over potholes and bumps, the cars were losing considerable energy through their shock absorbers. To minimize the bouncing, they compress air or liquids, which generates heat.

Zack Anderson and Shakeel Avadhany were in those cars. Two and half years later, they're MIT graduates with a company built around the idea of bouncy cars. Levant Power builds a gadget called GenShock, a shock absorber that doesn't dissipate the energy from a rocky ride but retains it.

GenShock isn't a "breakthrough" in the colloquial sense. It doesn't eliminate fossil fuels or shatter the price levels of other clean technologies. In fact, their tests show that depending on the type of vehicle and the way it's driven, gas savings will range between 1 and 6 percent.

But spread that device across millions of jittering vehicles, and the numbers become staggering. In 2007, medium-size and heavy trucks used 34 billion gallons of diesel fuel. According to E&E analysis, trimming 1 percent of that fuel would have saved 3.4 million tons of CO2.

Analysts of the trucking industry said they hadn't seen something like GenShock before. Some said previous energy-generating efforts, using electromagnets, never caught on.

Anderson and Avadhany are meeting with truck manufacturers and one of Detroit's Big Three carmakers. Transit operators have called, too, suspecting GenShock would reap huge fuel savings in their bus fleets. Levant keeps regular contact with military clients, whose vehicles navigate the roughest terrain there is. The technology isn't just for new vehicles, either -- it can also replace an old car's shocks.

Just two years ago, the idea was a contraption in a dorm room.

Feeding the battery through shock absorbers
After returning from California, Anderson, Avadhany and some friends began to think about their bumpy drive. They realized most shocks are designed to waste energy.

They started designing their own shock, one that would store the energy from those bumps but resemble a normal shock in every other way. Instead of radiating heat, their shock would use the bumpy motion to turn a small turbine, which would connect to a generator that feeds power to the car's battery.

In hybrid cars, that juice can immediately help power the car ahead. In standard cars, the juice can help power the onboard electronics -- the dashboard, the air conditioner, the radio. Since these usually get their volts from the gasoline engine, GenShock lets the engine focus on driving, which boosts miles per gallon.

Early designs were messy.

"In the bathroom, we had hydraulic fluid leaking down the drain," Anderson said. "It looked like a nuclear fusion project. I mean, you had tubes going all over, it looked really ridiculous. But it was that first working prototype."

Even though it worked, Anderson and Avadhany were college students -- not seasoned businessmen. They knew little of founders' agreements, marketing, management, or how to incorporate a company and make a sales pitch.

So they took their results around campus, where rich resources awaited their invention.

From the battlefield of ideas to the proving ground
MIT's technology licensing office, for example, researched where the device could fit in the market. They found the biggest bang in the biggest vehicles: heavy-duty trucks and military vehicles. A separate group, the Venture Mentoring Service, offered advice from industry "mentors" who had spotted and nurtured early-stage technologies before. Then, in 2008, the students started Levant Power to steer their idea.

Their first gig came from an old professor with industry connections. Ned Thomas, Avadhany's mentor and the head of the materials science department, knew someone at AM General, the company that builds the Humvee. Soon, the students were meeting with the company to see whether GenShock would be a fit.

Thomas said it's a very common way for MIT students to expose their work to the big leagues. MIT professors often consult with industry, as well as serve on professional committees that keep them plugged into the field. When they see a good idea, they know whom to call.

"You get to know a lot of people. Those people know people. At MIT, you're probably two phone calls away from the world authority on anything technical," he said.

To the military, Anderson and Avadhany learned, fuel economy was vital. Powering a Humvee in the field meant more than just buying the fuel; it also meant transporting it there and bringing a protective escort. Anderson said the Marines, incorporating all these costs, price a gallon of fuel at $400.

Moreover, heat loss presents a vulnerability to enemies who have infrared cameras that can spot panting Humvees in the field. "The fact that we're not dissipating energy in those shocks ... means that even something like that, fingerprinting the vehicle, is going to get tougher," Anderson said.

And, of course, there was the all-terrain element: As the ultimate SUV, the Humvee's shocks would surely pulse with energy.

Spending the summer with a Hummer
AM General sent over a Humvee, requesting a retrofit. Anderson, Avadhany and some friends rented a warehouse in south Boston and set aside a summer.

"This was street-legal. There wasn't any gun or anything on top of it," Anderson said. "They could have sent us one of those, but we wanted to do road testing around the city, which we wouldn't have been able to do."

The vehicle's returned to AM General now, where the company is inspecting it and sharing feedback with Levant. Meanwhile, in their offices just up the street from their alma mater, an improved prototype is whining and groaning through more tests.

They're watching the device to see how it fares in different conditions. In 18 months, they want to have a completed product that's ready to take to market. They think the product can have mass appeal, particularly in the military, where the high fuel cost means GenShock could literally pay itself off within weeks.

The payback period stretches longer for transit and long-haul trucking, but since fuel makes up such a large portion of their costs, Levant hopes they'll take a long look.

David Nguyen, an automotive engineer for the American Trucking Associations, said the idea of capturing energy from a suspension isn't new, but he hadn't seen anything like GenShock before.

"I think it hasn't been done this way, or it's another attempt that hasn't been widely used or widely tried," he said. "Conceptually, there's no reason I see why it wouldn't work."

Reprinted from Climatewire with permission from Environment & Energy Publishing, LLC., 202-628-6500