nDimensional technology is used to help optimize the operations at two combined cycle power plants, where the total capacity of the gas turbine and steam turbine, including additional power generated from duct firing, is bid into the energy market. The goal is to determine the most efficient possible firing regime (i.e. loading across combustion turbines, HRSGs, duct burners, and steam turbines) while meeting the maximum capacity and load-following commitments bid into the Regulation Ancillary Services Market.
Solution: Prediction models estimate the near-term plant demand and available generating capacity given grid and ambient weather conditions along with a plant equipment response model. These inputs are then used in real-time by optimization models to determine duct burner operation. The optimizer has been allocating fuel across plant blocks and sub-systems to minimize fuel costs while meeting capacity and ramp-rate commitments. It is estimated that leveraging the optimizer to more closely follow predicted demand saves between $875,000 and $1.2 million in fuel costs per year. The models integrated in the new control applications have resulted in more efficient dispatch of duct burners and an overall fuel savings.