Gasoline, short of nuclear, packs about the most energy per pound!

That's why it is so valuable, and why nations spill blood over it.
There's no easy 1 to 1 replacement for it.

That's why hybrids are a good step.
Gasoline is the superior, portable fuel... so we need to make it last.
We need cars that are light, effecient, and get 250 MPG.
This is possible. Think about this:

1 horsepower ( literally ) can move a 2000 pound wagon 5 miles per hour.
( Pioneer Days )

1 horsepower should move a 2000 pound car, 5 miles per hour.
2 horsepower should move a 2000 pound car, 10 miles per hour.
4 horsepower, 20 miles per hour.
8 horsepower, 40 miles per hour.
16 horsepower, 80 miles per hour.

You get the idea.

As soon as people get it in their head that we CAN have a 2000 pound car that goes 80 miles per hour and needs say, 20 Horsepower when you add accessories... then you can get 250 MPG, or you could cut out the gasoline, and solar becomes feasible.

A 200 HP solar car is not impractical, it is mathmatically, impossible.
One square meter ( 39" x 39" ) of sunlight only has 1500 watts.
One square meter of sunlight has 2 horsepower.
But solar cells only convert about 15% of the energy to electricity.
So now you need 3.3 square meters ( about the entire car roof ) to get 1 horsepower of "live" solar energy.
There are physical limits, that no amount of technology can overcome.