Fantasy time: solar farming

If a breakthrough of solar technology occurs and the cost of photovoltaics came down enough that we could deploy panels all over the countryside, what is the maximum conceivable production? Well, if we covered 5% of the UK with 10%-efficient panels, we’d have 10% × 100 W/m2 × 200 m2 per person ≈ 50 kWh/day/person.

I assumed only 10%-efficient panels, by the way, because I imagine that
solar panels would be mass-produced on such a scale only if they were
very cheap, and it’s the lower-efficiency panels that will get cheap first.
The power density (the power per unit area) of such a solar farm would be 10% × 100 W/m2 = 10 W/m2.

This power density is twice that of the Bavaria Solarpark (5W/m2)