Energy delivery scheduling and realizability in deregulated electric energy market

In the new deregulated electric power market, energy transactions are generally processed in terms of hourly energy delivery. The paper studies the relationship between generation level schedule, energy delivery schedule and physical ramp-rate of a generating unit. It is shown that although ramp-rate constraints are satisfied in traditional unit commitment problems, taking a generation level schedule as an energy delivery schedule may not be realizable. The admissible region of energy delivery is established as a set of recursive equations by using the maximum principle in optimal control theory. This set of equations provides a sufficient and necessary condition to check whether an energy delivery schedule is realizable.