Demand-side energy flexibility (DSEF) is emerging as an effective measure to stabilize the renewable power-based grid operation and reduce building greenhouse gas emissions and energy costs. An aggregated quantification function that can effectively capture the technical and non-technical aspects related to buildings and building energy systems is still needed. This paper presents the formulation of an inclusive DSEF quantification function, termed as building energy flexibility potential function (BEFPF), by using fuzzy multi-criteria decision analysis and domain knowledge. The DSEF quantification function developed can consider the dynamic nature of buildings and building energy systems by simultaneously incorporating several factors such as system performance, charging/discharging percentage of storage systems, grid support, the cumulative energy consumption of mix, load/power shifting potential, price elasticity, acceptable delay time, temporal fluctuations, occupants behavior and comfort, rebound energy, emission control, and self-generation and self-consumption potential of the building. Each factor was assigned a weight by using the fuzzy analytical hierarchy process. The BEFPF was then used to evaluate the flexibility potential of a grid-connected building integrated with an air source heat pump and a thermal energy storage system through a simulation exercise.
Keywords Buildings, flexibility function, thermal energy storage, quantification, demand-side flexibility