Closing the energy flexibility gap: Enriching flexibility performance rating of buildings with monitored data

Quantifying and rating energy flexibility in existing buildings will become increasingly important as building energy services become electrified. Flexibility ratings based on building design specifications have shown potential to complement energy performance certificates and enable the comparison between buildings. However, relying on physical models and standard boundary conditions could lead to a ‘flexibility gap’: a difference between predicted and actual flexibility. This article investigates the incorporation of monitored data into design-based flexibility ratings, using an existing rating methodology and two UK case study domestic buildings. We firstly examine whether the current rating methodology can accept monitored data, and find it is able to apart from the final step of rating. We then devise two methods of calculating the metrics required for the flexibility rating, based not on physical models but on data. Using these methods, we examine the impact of the standard operational modelling assumptions on the flexibility metrics compared to using data-informed inputs, which highlights some discrepancies and some concepts in the flexibility rating methodology for which monitored data may be very difficult to obtain (e.g. recovery time). Finally, we suggest how to improve the usefulness of flexibility ratings by incorporating additional information based on monitored data.