If we were able to cooperate globally, we would already have an international super grid (loss of only about 1 to 5 percent energy per 1000 km(. And we would already have had huge solar panel parks in China's Gobi desert, in Australia, in India's desert, in the Sahara desert, and n the deserts of the Americas, and connecting them all. So that whenever it's night time in a region, that region imports solar power from regions that are exposed to the sun. Such a super grid would also allow to export excess energy from other renewables, and import when there's, for example, less wind.

Only about 100k km^2 of solar panels are enough to meet today's global demand. But we need two or three times more so they can be placed strategically over the world, and always be producing enough solar energy. Anyway, those 100k km square are about 1 percent of the Sahara Desert, and about 5 to 10 percent of the Great North American Desert). Also, keep in mind that the world would also supply wind, tidal, hydro and geothermal energy, among many others. So we don't even need 100k km square of panels...