Doug Miller wrote:
I think the wave of the future is going to be in electric vehicles, using the
emerging "ultra-capacitor" technology. Capacitors have three advantages over
batteries for use in powering vehicles: they charge in seconds instead of
hours, they're able to deliver power more rapidly when needed (e.g.
accelerating from a dead stop, passing, or climbing hills), and the
ultra-capacitor shows promise of attaining a much higher energy density (power
to weight ratio) than is possible with any current battery technology.

I don't know anything about these "ultra-capacitors" BUT I have had
lots of experience with various electrolytics and if the construction
is suitable for high energy output and a failure, such as a major
penetration were to occur there would be a VERY LARGE release of
energy. :-)
...lew...