That's a lot of solar generators. So the sooner we start, the sooner we'll get there. The interesting thing is, just as better computers help us design and build still better computers, increasingly available energy will drive the cost of existing energy down, reducing the cost of energy used to build and maintain new capacity.
If we can only power the world half the day with solar, then that's a large fraction of our power that we don't have to burn oil or coal or biomass (food) for. If we can only power half the world half the day, it's still a win. If we can only make it through part of the night before lighting up an oil generator, it's still a win.
It astounds me that we're living in a blowtorch and we do essentially nothing with it, fight wars over oil, spew oil and emissions all over the world, and watch the elderly and poor die from lack of heat or cooling.