So if the French population switched to electric, we would need 38m x 800W = 30 gigawatts. We have 58 nuclear cores of ~1GW each as a comparison (80% of our energy) - with the upside that nuclear plants produce by night as much as by day, which causes a lot of issues, therefore 800W between 10pm and 6am might allow a much more efficient (and ecological) use of our nuclear energy.