An Optimal Operational Planning Method for Energy Supply Systems in Consideration of Equipment Startup/Shutdown Costs.

Abstract

A method of determining the operational strategy for energy supply systems in consideration of equipment startup/shutdown costs is proposed. This operational planning problem is formulated as a large-scale mixed-integer linear programming problem, in which the on/off status and energy flow rates of equipment are determined so as to minimize the sum of operational and startup/shutdown costs over the period considered. By utilizing a special feature of the problem, an algorithm for solving the problem efficiently is proposed, in which dynamic programming is adopted to determine the most cost-effective path regarding on/off status, the branch and bound method is modified to enumerate multiple candidates for on/off status, and a strategy is incorporated to reduce the number of candidates by using lower and upper bounds for the objective function. Through a numerical study on the operational planning of an energy supply system for district heating and cooling, the effectiveness of the proposed algorithm is ascertained in terms of computation time, and the effect of startup/shutdown costs on the operational strategy and cost is investigated.