Fuel is my word for time, energy, money and anything else that runs out. Everyone has a different sized tank, and camp empties all of them faster than any other job I know. A leader has to track the levels across the whole team and make room for people to refill. That includes your own tank, which camp people are famous for ignoring.
This is the short version. The full lesson, with the story behind it, is in the book.
Take The Summer Camp MBA with you, or get the field notes by email while you work through the lessons here.