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It's also unrealistically good as you don't get high noon insolation for 9 hours a day.

You do however get some power for more than 9 hours per day. Also, panels can go well past 200w/m at a theoretically possible 600w/m the numbers look rather different. Cars are only going 12-15k miles a year so hit 40miles a day and you generally stop needing charging stations.

The amount of power incident from the sun is roughly 1000 W/m^2 in a sunny area. Good Silicon PV panels will capture 20% of that power generating 200 W/m^2 at peak. Getting anything more than that is going to be too expensive for a car application.

Pulling 600 W/m^2 from a PV panel may be theoretically possible, but the world record efficiency for a PV device is still less than 50%. To get above 40% efficiency you need to use very expensive multijunction devices and solar concentrators (i.e. not going to work on a car).

I generally agree today, but that says little about the long term.

As solar panels have gotten cheaper installation costs have become more important which has pushed up panel efficiency. Cheap but good panels are up to ~23% efficiency where they where ~18% fairly recently. What’s interesting is these trends seem to be continuing with serious research into various affordable multi junction cells going on.

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