and recharging that to 80% full in 30 minutes is going to need a 1MW supply.
It's fine. Musk also said that the truck's Arc-Chargers will be powered by solar. So say, 5,000m^2+ of panels per charge point. Batteries not included. But I guess trucking is an application where careful planning could combine charging with mandatory rest breaks. If it can't, then the economics will be tricky, especially with just-in-time deliveries and contract penalties. ISTR a number of freight customers insist on specific and narrow time windows for deliveries, or penalties are applied.
I'm also curious about the Roadster's performance and range claims as those seem to suggest significant advances in batteries, drive train, aerodynamics or all three.. Which could be easily challenged on any race track.