Flexibility potential of energy intensive industrial processes

Abstract

The power system is undergoing a significant change in power generation. As the integration of renewables increases, thus do the temporal and spatial variations in power generation. Also electrification of industrial processes due to decarbonization goals increases demand and therefore the strain on the power system. These require solutions that partly come from the demand side. By controlling energy consumption, the volume difference between production and consumption can be lessened, and therefore the stability of power system increases. This thesis focuses on energy intensive industries, and their flexibility potential. First, flexibility as a concept is introduced and its role in the power system. Then the focus shifts to flexibility of industrial processes. Flexibility can be categorized into flexibility resources, services, and products. Flexibility resources can produce flexibility services that can be traded as flexibility products. This thesis also presents typical flexibility services of industrial processes and methodology on finding flexibility resources within energy intensive industries. The purpose of the thesis is to demonstrate how industrial energy management system and process optimization system exchanges information about flexibility potential of an industrial process with high energy consumption and what kind of flexibility services such industrial process can produce. The energy management system receives information about flexibility potential in the form of a matrix, of which rows represent different durations of different kinds of flexibility services. The total number of rows depends on the types of flexibility services and their duration. The total number of columns represents the time resolution of flexibility services. Elements in the matrix contain information about upward and downward capacities of the process within a timestep and service represented by column and row respectively. The information exchange is demonstrated with a demonstration case consisting of aeration process of a wastewater treatment plant. The demonstration case shows that there is a significant amount of energy flexibility potential (hundreds of kWh) available in this process, which is evaluated with different flexibility criteria.