How does energy work?

Tapping a generator costs energy (1 per tap on most chains, 2 on premium chains). Merging and delivering are always free. Energy refills by itself: 1 point every 2 minutes, up to your cap. Refill pauses while you're at the cap — so playing down your energy before a break means nothing is wasted. Honestly: energy is limited on purpose. The game is designed for a few relaxed sessions a day, not one long grind.