Not so sure about
the environmental disaster bit Rodger, as certainly where my brother lives in Scotland, leccy comes mainly from renewables. The coal fired power station near him recently closed its doors after 45 years of operation. Ok, I'm not entirely convinced either, but I do know that when coal and oil run out and become prohibitively expensive in this country, there will always be alternative such as nuclear etc. Nuclear could be doing the job right now, but it's too much of a political hot-potato. In a few years time when the tree-huggers are freezing their arses off at home and suddenly forget their 'ideals', then sources such as nuclear can be introduced on a wider scale.
Battery power - might be the case that you buy the vehicle but lease the battery as used to (maybe still does) with certain brands of hydrid cars. Does the Renault Twizzy not do this? So your running costs won't be quite as cheap as you anticipated once you factor in the cost of the battery lease, but at least you'll never have an expensive battery to buy, which will help the used bike/car market and residual values.
Silent running... do cars drivers ever pay attention anyway? Perhaps the ability to sneak up on them by stealth and zip by them is an advantage.
My best mate is a highly qualified electrical engineer. Chatting to him one night about it all, he is absolutely convinced that electric vehicle fit the bill for most people's needs and will be big news. Reckoned hybrids will be the way forwards for those needing to cover longer distances - with the electric motor being supplemented by a small capacity tubo-charged petrol/diesel engine. Spelling out the benefits of electric motors, their simplicity, lack of maintenance required, reliability etc, I think they have a lot to offer motorcyclists in the future - particularly when battery development means greater distances.