Industrial application of a model predictive control solution for power plant startups

This paper reports on the development and a successful MPC implementation for startups of combined-cycle plants. Minimizing startup times is important for energy utility companies to reduce operating costs due to lower fuel consumption and lower emissions. The new controller regulates the gas turbine loads while keeping the main operating constraints (steam turbine stresses) within their allowable ranges. The real-time implementation has been particularly challenging since the MPC required solving an optimization problem with more than 3000 variables and 4000 constraints at every control step. The critical enablers for this technology were the development of efficient algorithms to solve large scale quadratic programming problems with highly structured problem data, and the use of an advanced control platform and software application tools that provided the flexibility for a seamless prototyping. The MPC solution was implemented in the 480 MW 9H combined-cycle plant at Baglan Bay, South Wales The first trial of the MPC startup controller showed time savings of 52 minutes, fuel savings of 62900 pounds-mass (Ibm) and emission reductions of 117 pounds-mass, with respect to the previously existing startup controller.