text: The i3 can be fitted with an optional ‘range extender', which is a small petrol-driven generator that charges the vehicle as you drive.
  For example, a driver can tell the automated charging system to keep the batteries at 90 per cent and, day to day, for short runs to the shop, the range extender won't kick in because the batteries are likely to have been charged overnight.
  However, if driving out of town, when the battery hits the pre-determined level, the petrol engine starts. While it can't fully replace the energy being expended, it can slow the rate at which the battery depletes, giving a top range of around 330 kilometres.
  EV manufacturers speak about the ‘cost of ownership', which is not unlike the way consumers think about their mobile phones. Rather than thinking “can I afford $800 for a phone”, consumers are used to thinking “can I afford $60 a month?”
  In the case of an EV, the cost of ownership is that ‘fridge' level of electricity use), and the resale value of the vehicle.
  There is, of course, the cost of the battery. BMW is guaranteeing the i3's battery for eight years, and the company points out that BMW buyers often upgrade their cars on a three to five-year cycle. And as the battery is made up of eight separate ‘pods', the company can replace faulty pods without touching the others.
  That's all interesting enough from a consumer's perspective, but where EVs start to get really fascinating is in the way they will change existing energy markets. That will be determined by how consumers use EVs in the real world.
  BMW thinks it has seen the future in this respect. As described above, it isn't battery swapping. Surprisingly, it's not even likely to be a national network of charging stations.
  If you drive 300 kilometres to spend a night away somewhere, there is a cable to plug into any normal 10A power plug. It'll take 11 hours to fully recharge, but then you'll probably be eating, drinking, sleeping and so on.