The 100 km^2 aka solarcity's "blue square" is US electrical output, not world and not total energy. There's a 36x difference between the two. US insolation is

The 100 km^2 aka solarcity's "blue square" is US electrical output, not world and not total energy. There's a 36x difference between the two. US insolation is around 5.5 kWh/m^2/day. For a non-tracking array in Arizona it's about 6.5-7 [1]. Total energy collection would be almost 10^20 joules with 100% efficiency. US electricity consumption is about 1.4 * 10^19 J [2] so it would only require solar panels with 15.5% efficiency. Average is around 17%. [1]: https://www.nrel.gov/gis/solar.html https://www.nrel.gov/gis/solar.html [2]: https://en.wikipedia.org/wiki/Orders_of_magnitude_(energy) https://en.wikipedia.org/wiki/Orders_of_magnitude_(energy)