Don’t do this:
Your Prius, unless it is a plug-in hybrid, only TAKES one fuel. Gasoline. That’s not an alternative. Regenerative braking is a more efficient way of using the energy usually wasted when a car slows down. How did it move in the first place ? from electricity stored from regen, which ultimately came from gasoline moving the car above 25 mph.
Unless it has a plug AND a gas cap, or just a plug; its not alternative, its just more efficient. If you drive on CNG, Bio-diesel, or electricity directly, then you can have the plate. It doesn’t belong on a Prius.