Your interesting article ‘Oxford in 2065’ had two sections on transport. The waterbus service is a nice idea; but have Christopher and Wendy Ball done any traffic modelling to estimate the almost certainly tiny effect of such a service on traffic congestion?
As Lord Drayson says, the battery is one major problem with electric cars. Another is that as things stand, they pay very little towards the cost of road maintenance, since by definition they pay no fuel duty.
A proven approach which would address both pollution and congestion, and employ existing technology, is road pricing, as used in London, Stockholm and Singapore. Oxford would be an ideal place to implement it; and contrary to popular opinion, such a solution is acceptable to citizens, provided it is explained and justified.