You're still left with the problem of where the power comes from.
While EV is a fringe technology it is easy to have a few running about. But if 20% of cars were replaced with EVs you'd need to find a lot more electricity than is available now.
Most countries don't have surplus electrical generation and indeed many already have a shortage.
I hate to be so pessimistic when it comes to new energy sources, but I do not see the viability /benefit of a recharging system that requires interchange of an energy storage vessel. Would anyone feel safe with energy tanks that may present a safety hazard? The mechanism that would allow a quick interchange, would be very likely the failure mechanism during collision.
Drones are, in essence, flying autonomous vehicles. Pros and cons surrounding drones today might well foreshadow the debate over the development of self-driving cars. In the context of a strongly regulated aviation industry, "self-flying" drones pose a fresh challenge. How safe is it to fly drones in different environments? Should drones be required for visual line of sight – as are piloted airplanes? Join EE Times' Junko Yoshida as she moderates a panel of drone experts.