I don't know if y'all have such things on that side of the pond, but here in the States many of the large cities have "ozone alert days."

A bad brush in one of those electric motors can start producing plenty of ozone (with every arc), and even if they never have a mechanical or electrical fault, they're still going to emit tons of lead-acid, or some similar heavy metal toxic soup, over the course of their lifetime. Where are people going to dispose of all those batteries?

As for fuel cells, I'm not sure about catalyst consumtion, but at least the normal daily exhaust is plain old potable water. Now there's an idea worth chasing down. Energy use that produces (or at least restores) a commodity instead of consuming one. What are the economic implications of that?