Optimal Scheduling of a District Heat System with a Combined Heat and Power Plant Considering Pipeline Dynamics

Abstract

This paper presents two new mixed-integer linear programming (MILP) models for more flexible operation of a combined heat and power (CHP) plant connected to a district heating load by a pipeline. The optimization models consider the heat-storage capabilities of the pipeline to better react to volatile energy prices and heat demands, varying both the flowrate and temperature of the hot water coming out of the CHP plant. They rigorously account for varying time delays, in a simpler (linear) way than previous works. The new scheduling formulations achieve a very good computational performance by relying on either a discrete-time or hybrid discrete/continuous-time representation, where all time slots of the grid are preassigned to a given period with constant price and demand (e.g., an hour of the day). Results for a motivating example inspired by a German system show additional revenues of 345 k€/year for a 10 km pipeline with a diameter of 0.7 m (3850 m 3 ), compared to operating the pipeline at a constant temperature. This value is strongly dependent on the storage capacity, increasing to 1415 k€/year for a volume of 10,000 m 3 .

Industrial Demand Side Management of a Steel Plant Considering Alternative Power Modes and Electrode Replacement

“…Due to the strong time-dependence of these energy-related concerns, effective scheduling is essential in DSM, and it has been identified as a key challenge in industrial deployment of scheduling solutions, especially when a complex manufacturing process is involved. , Therefore, many recent studies have looked at various aspects of DSM applied to a variety of industries including air separation, − cement making, − combined heat and power plants, , and pulp-and-paper …”