It would be nice if it took 1 or 2 minutes instead of 3 to restore an energy. Considering you start off with 80, that's FOUR HOURS you'd have to wait for it to restore (not including the free 30 energy from the ad, and the lottery). It's the same for the events that use their own energy. There's no ads or lottery for those, so when you're out, you gotta wait a while.