Before revision:  We show that the classical no-arbitrage relationship between spot and forward prices holds through the well-posedness of an expected profit maximization problem for an agent producing and storing a commodity while trading in forward contracts. A consequence of this is that the forward price of energy can be seen as  risk-neutral expectation of the spot price at maturity .
After revision:  We show that the classical no-arbitrage relationship between spot and forward prices holds through the well-posedness of an expected profit maximization problem for an agent producing and storing a commodity while trading in the associated futures contracts. In this framework, the relation between the spot and the futures prices holds through the well-posedness of the maximization problem. We show that the futures price can still be seen as risk-neutral expectation of the spot price at maturity .