Re: 50 miles???
"you'd need a 2sq.km field per charger just to replace power used in one hour"
Most of the big solar installations I've seen do seem to be just that. Solar panels in fields. Even with dense coverage, you could still use the field to graze sheep. But I wonder if it's possible to share space with crops that are normally hand-picked? Leave larger gaps between the panel rows to allow machinery to plant or do what needs doing to crops happy to grow at least partially shaded by the panels. I'm sure farmers or solar panel installer type people could come up with ways to co-exist and more or less double the productivity of the land and still keep the panels safely wired together such that they don't get cut off by ploughing or hungry sheep.