So when you charge them up i guess they dont contribute to green house emissions...
yes or no...
If you plug it into the wall then yes, of course.
But the pollution is less because power stations which use fossil fuels have (or ought to have) effective emmisions control systems in their exhausts.
Charge them at night on low rate.
Partially charge it from a solar panel or wholly from solar panels.
Got a stream? Use a micro or pico turbine and use that to put in some or all of the power it needs.
If there was an electric motorcycle which could keep up with the traffic I'd be down to the shop to get one yesterday - or sooner.
I'll keep my three gasoline bikes as spare.
* It's the quietness that I like more than anything else.