I was reading an article in Road and Track last week, and found a very interesting feat accomplished at Nurburg , a 911 GT3 R led the 24 hours of Nurburgring, against 198 other production based race cars, for at least 8 hours and was surmised to have won if the flat six 4.0 liter hadn't seized up with two hours of the race remaining.
The car was sponsored by a Porsche factory supported team Manthey Racing, and held two combustion engines a battery and each front wheel held a eclectic motor. (The same model of hybrid Porsche used in the race on the Green Hell, no. 9 was the Manthey car used in the race.)
Now lets talk Green.
Now this in itself kinda proves the technology is certainly there to expand into new fields. But the question remains in this instance, if you can do this on the track for the first time and perform relatively well. (Starting on a good test frame, such as this Eagle or similar vehicle might prove good results similar to those at Nurburgring, understand modern war maneuvering and GT racing are two different planets entirely, but then again, so was hybrid technology in racing just a short time ago.)
What about improving vehicle endurance and applying this technological innovation to military vehicles. Modern Armies hold a vast array of military vehicles, but what you may be thinking of is hybrid tanks...I don't think the world is quit ready to accomplish that feat. However from support vehicles, trucks and even supply vehicles, it would be difficult. However starting small with for say utility vehicles (standard four wheel people movers). Would be a great place to start. As with any new technological innovation in warefare, reliability and sustainability would have to be paramount if this innovation is to work.
Having a hybrid vehicle that can still move loads, and conquer terrain that current military vehicles face today would have to be a must, and the hybrid system mustn't require a boat load of field techs to keep it running, and increase vehicle endurance enough to make the endeavor worthwhile.
The goal? Extend vehicle range and make less fuel, do more, and this would snowball (in rough theory) into having to burn less fuel to move fuel to the field, and cut down on numbers of personnel (even if slightly) needed to insure this, all knowing that personnel costs, being the most expensive component in the design in any modern Military force.
Even like the GT 3 R, which was pitting an average every 10 laps, while competing Audi R8s, and even an interloping F 430 on average every 8 laps. It's only a short walk in the thought process to imagine the benefits of applying this technology to certain military vehicles, still don't be expecting solar powered tanks anytime soon.