Quantification of the energy flexibility of residential building clusters: Impact of long-term refurbishment strategies of the italian building stock

A major refurbishment of the building stock is necessary to achieve the objectives of the energy transition. In addition to decreasing the overall energy demand, the energy efficiency of buildings can create a non-negligible reserve of flexibility and resilience for the entire energy system. Long-term refurbishment strategies can have an impact on such potential of the building sector that is still not widely exploited. In this work the objective is to quantify the influence of long-term refurbishment strategies, planned until 2050, on the energy flexibility reserve of the entire building stock. Reference clusters of residential buildings have been modelled to represent the current and future scenarios of the Italian building stock. Lumped parameter models representing archetypes of residential buildings are implemented to represent the Italian building stock. Current statistics on the composition of the building stock have been combined with European refurbishment targets to 2050 to define the current and future scenarios of the Italian building stock. Since the topic of quantifying the energy flexibility of clusters of buildings is still rather open, this study proposes an analysis based on a combination of different indicators derived from the literature and proposed ad hoc by the authors. They include flexibility curves, that correlate the demand of the cluster to the penalty signal (e.g., a price signal), and flexibility indicators for the comparison between the scenarios with and without activation of energy flexibility. The results quantify the impact of Italian building stock refurbishment strategies on flexibility reserve and efficiency targets. It has been estimated that the maximum electrical power shiftable (both upward and downward) by activating the energy flexibility of the whole building stock can reach 17.9 GWe in 2050. While in terms of energy, the following amounts of average daily shiftable energies have been obtained: from −34.4 to + 13.6 GWhe in 2030, from −75.4 to + 16.2 GWhe in 2040 and up to −113.5 to + 45.8 GWhe in 2050, that represent around 2% of the present Italian electricity demand.