That’s probably it. I thought maybe the US Dept. of Energy or one of the National Labs (Los Alamos or Livermore) were funding the buses.
A hybrid form of flywheel technology is now in operation on one small section of the UK railway network. Called the Parry People Mover it’s operating on the Stourbridge branch line. One unit is now in operation, with two more on order. Here is the press release from the railway company and the Parry’s web site
Here are details of the actual technology behind the People Mover
I think one of the proposed advantages of using fiber composites was that instead of blowing up, the material “frizzes” (my word), decomposing into a relatively harmless, self-braking fuzzball. That’s pretty old information, though, I never heard how well it worked.
Recently the idea of flywheel energy is also getting interest for large, fixed installations used to buffer the power grid.
There’s an article about this in a recent Science News:
Registered subscribers only: Spinning into Control (5/19/2007)
High-speed flywheels could replace batteries in hybrid vehicles and help make the electrical grid more reliable.
Again, sorry for the subscriber link. Among other things, the article says the higher speed allowed by composites more than compensates for the lighter material. One way they increase effeciency is to encase the wheel in a vacuum chamber.
This thread starts out talking about “ordinary” electric cars and after a couple of posts switches to a discussion of flywheel cars. IMHO, don’t look for them any time soon. If ever.
For cars, I agree heartily. It seems to me that the practical efficiency of a flywheel system increases with its mass, so using a flywheel to store and release the momentum of something as light as a car just doesn’t make sense. It makes more sense, or will make sense sooner, in applications like mass transit where you have to start and stop a heavy train or bus frequently.
Flywheels aren’t so great for long term storage. What they’re great for is load leveling, soaking up energy that you’d otherwise waste in braking, and then releasing it relatively soon when you start up again.
It’s analogous to the batteries in smaller electric vehicles, which for long trips are only as efficient as your power source (which might be quite good), but can actually save energy (through regenerative braking) in downtown start and stop traffic.
This is why flywheels are so attractive for power grid storage. Power plants can work more efficiently if they don’t have to vary their output much. You don’t need or want to store enough power to back up the system for any length of time. But it can help a lot to level out peaks and slumps in demand.