"I think there will be a demand for hybrid engines in SUVs, larger cars and large trucks, because people like the space and utility of a larger vehicle, but they don't necessarily like getting lousy gas mileage," says Joe Lorio of Automobile Magazine. 

A hybrid is a traditional gas engine working in concert with a battery-powered electric motor. So how does a hybrid save gas? By capturing the energy a car generates while it's slowing down -- what's known as regenerative braking. 

"When you decelerate and lift your foot off the accelerator pedal," says Mario Maiorana of General Motors. "We use the vehicle's momentum or the kinetic energy of the vehicle to feed the system that turns the motor generator, creating electrical energy that we can then store in the 42-volt pack for use at a later point." 

That potent 42-volt battery runs many of the vehicle's systems formerly dependent on the gas engine for power, saving fuel and more. 

"When you come to a stop, the internal combustion engine will shut off and therefore you're not burning fuel at that point in time," says Maiorana. "In this case this vehicle saves between 10-12% fuel economy benefits over the base trucks similarly equipped. Also if you're not running in idle you'll see a drop in greenhouse emissions." 

Today, you can already find hybrids on smaller cars. Next year GM and other manufacturers will begin offering hybrid engines on larger vehicles and those of us who need the extra room can feel a little less guilty.