Those of us who have been following the enthusiasm surrounding hybrids and alternative fuels have wondered how this move away from typical gas-powered engines is going to affect trucks and SUVs. After all, it's often the case that when a vehicle gains fuel economy, it loses power and capability, and for people who tow, that's an absolute deal-breaker. So how can trucks take advantage of hybrid technology without losing the ability to tug a trailer?

The current answer is to use a stouter gas/electric hybrid system. When done right, it improves fuel economy in the city without sacrificing capability. However, there's another way to use this technology, which could improve towing capacity and would do it with better highway fuel-economy numbers than a regular hybrid: a diesel/electric system. With this combination, the electric motors could power a vehicle at low speed and assist in power around town, using regenerative braking to recharge the batteries. Then on freeways and at higher speeds, the diesel engine would take over, providing the torque truck guys need and the excellent fuel economy diesel fans have come to expect. Clearly, if it were that easy, this system would already exist on every full-size truck and SUV. But there are some hurdles that have to be overcome, the biggest one being cost. Diesel engines are already pricey to produce, as are hybrid systems. Having both in the same vehicle could prove prohibitively expensive.

Believe it or not, research and development of diesel/electric hybrids is already taking place, but it isn't in the automakers' R&D centers; it's happening on school campuses. For several years, General Motors and the U.S. Department of Energy sponsored a competition known as Challenge X. The third such event included student teams from 17 universities who were given the task of designing and building a new-at-the-time hybrid 2005 Chevrolet Equinox, the goals being reduced emissions and, hopefully, improved fuel economy. Entries included hydrogen power, plug-ins, ethanol, ethanol/hydrogen, reformulated gasoline, B20, and regular diesel. After coming up with proposals, the schools that were accepted into the event spent a year working on computer simulations, then each school received its project SUV. Keys in hand, the students had two years to make the theoretical a reality.

We had the opportunity to drive the contest-winning entry from Mississippi State University, which uses a combination of an electric motor and diesel power. What made this vehicle stand out for the judges was its 48-percent increase in fuel economy over stock, how close it is to being production-ready, and that it's stout enough to handle cross-country jaunts (the guys put more than 15,000 miles on their vehicle, which is more than the next four teams did combined).