I'm not sure how to unpack this. If there isn't energy scarcity, why does petroleum cost money? Scarcity isn't just a question of production, but also one of consumption. With some goods (e.g. food), we could reach a point where the entire population of the world cannot consume more. With others (energy is a salient example), there seems to be no upper limit on consumption. There will always be a finite amount, and people want to use it differently. This is exactly the problem markets are purported to solve.