What I can't understand is why our cars can't have as many power sources as possible. I think engineers seem to think inside of boxes. For many years I was telling my friends that hybrids were the way to go but I always envisioned the electric motors being the primary source of propulsion (instead of being just an assist to the gas motor) with batteries powered by a turbine generator. It amazes me that the current crop of hybrids still rely on internal combustion engines. When used for the primary means of propulsion, internal combustion works well because it performs solidly over a wide range of rpms.

The few experiments with using gas turbines for direct propulsion didn't work out well because turbines generally are much more efficient and trouble-free when run at high and steady rpms. However, they are hugely efficient for electrical generation when you hook them up to generators and alternators. It's what you see in aircraft auxilliary power units (APU's). One other great benefit you get using turbines for your power generation is that they can run perfectly well on a wide variety of fuels. You can feed them fuels such as alcohol, propane, methane, gasoline, generally anything that will burn and they just purr along without the expensive modifications IC engines require.

So here's my perfect vehicle - a lightweight turbine hybrid with it's primary propulsion driven by individual electric motors on each wheel, running off of a battery pack consisting of numerous generic nickel metal hydride D cell batteries in an easily replaceable grid. Each electric motor provides regenerative braking through electronic circuitry. An aircraft style APU is inside the car to keep the battery pack topped off or for running the accessories. The entire horizontal surface of the car is solar cells for charging batteries on sunny days. The car has multiple fuel tanks including gasoline as well as a compressed source such as propane or CNG. A small tank will also receive alcohol so, in case you're out in the middle of nowhere with only a bottle of tequila you can get home.

Oh, and just for the heck of it, the passenger seat floorboard contains a set of pedals that you can pump to generate supplemental power and get a little exercise while on long trips.

Why not?