Long-term Operation Planning of District Heating and Cooling Plants Considering Contract Violation Penalties

Urban district heating and cooling (DHC) systems operate large freezers, heat exchangers, and boilers to stably and economically supply hot and cold water, steam etc., based on customers demand. We formulate an operation-planning problem as a nonlinear integer programming problem for an actual DHC plant. To reflect actual decision making appropriately, we incorporate contract-violation penalties into the running cost consisting of fuel and arrangements expenses. Since a yearly operation plan is necessary for check whether the minimum gas consumption contract is fulfilled or not, we need to solve long-term operation-planning problems. To fast and approximately solve long-term operation-planning problems, we propose a decomposition approach using coarse (monthly) approximate operation-planning problems.