Since you're using the gas anyway, why not convert the heat from your car engine into useful electricity?
That's the basic premise behind the work of Terry Tritt, professor and director of the U.S. Department of Energy's Center of Excellence in Thermoelectric Materials Research at Clemson University.
Thermoelectric generators are currently used to convent radioactive heat into electricity by NASA for deep space probes. The same technology could be applied to the automotive combustion cycle, which wastes more than 60 percent of its energy through heat, according to a paper Tritt delivered at the Alan MacDairmid Memorial Nano Energy Summit in Dallas in early October.
"Even at the current efficiencies of thermoelectric devices, 7 to 8 percent, more than 1.5 billion gallons of diesel could be saved each year in the U.S. if thermoelectric generators were used on the exhaust of heavy trucks. That translates into billions of dollars saved," Tritt said in a statement.
Of course, it's not as simple as stuffing a thermoelectric generator into the trunk of your car. The success of the proposal rests on developing more efficient thermoelectric materials, according to Tritt.
But there are some options on the market for harnessing at least a portion of that unused energy, according to a recent article in Popular Mechanics, even if they are not completely efficient.