I recently returned from 3 weeks vacation in the UK, where electric bikes seem quite popular. In addition to the price of petrol (about $4.50 per US gal), traffic congestion in the towns and the lack of car parking facilities are factors that favour their use.
The most popular model that i saw was like a ladies bike with a split upper downtube, which made a space to carry the battery. The battery could be removed when it was parked.