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The building sector is crucial in all of the possible net zero scenarios suggested for the European Union. In this area, the Italian situation is exemplary. Italy suffers from an aging and low-performance building stock and needs to increase its annual rate of energy retrofits in order to achieve its 2030 and 2050 targets. Even though since at least 2007, several different incentives schemes intended to stimulate energy-efficiency interventions have been in place, Italy has not been sufficiently able to promote deep retrofits. In 2020, in order to help the economy recover after the lockdowns that were introduced to face the first phase of the COVID-19 pandemic, the existing incentives were increased to up to 110% of investments for interventions that improved the energy class by at least two grades. This so-called “Superbonus” was also extended to the public social housing sector thanks to a credit assignment scheme. Given the results of this provisional phase, a possible policy roadmap for the energy renovation of the residential and educational building stock in Italy is presented in this paper through an analysis of data related to the implementation of current instruments in terms of number of interventions, investment needed, energy savings and evaluation of potential benefits and costs that can derive from an increase in the current deep-renovation rate. Through definition of a long-term renovation strategy, this paper illustrates how market barriers and other issues in instrument design can be tackled and how policymakers can help to develop a sustainable long-term roadmap for energy-efficient buildings. Beyond the residential sector, public buildings, particularly educational buildings, are taken into consideration as well, as they are places of collective use that represent the social values of fairness and sustainability and can therefore have an exemplary role for private initiatives.

The Energy Performance of Buildings Directive 2018/844/EU introduced the smart readiness indicator (SRI) to provide a framework to evaluate and promote building smartness in Europe. In order to establish a methodological framework for the SRI calculation, two technical studies were launched, at the end of which a consolidated methodology to calculate the SRI of a building basing on a flexible and modular multicriteria assessment has been proposed. In this paper the authors applied the above-mentioned methodology to estimate the SRI of the Italian residential building stock in different scenarios. To this end, eight “smart building typologies”, representative of the Italian residential building stock, have been identified. For each smart building typology, the SRI was calculated in three scenarios: (a) base scenario (building stock as it is); (b) an “energy scenario” (simple energy retrofit) and (c) a “smart energy scenario” (energy retrofit from a smart perspective). It was therefore possible to estimate a national average SRI value of 5.0%, 15.7%, and 27.5% in the three above defined scenarios, respectively.

This paper proposes an analysis methodology that can be applied by governments and local administrations to evaluate energy retrofit programs that involve entire building categories. Through a simulation based approach, that combines detailed energy modelling and algorithmic optimization, the analysis methodology is aimed to assess the magnitude of achievable energy savings for various retrofit levels along a cost-optimal path towards achieving net zero energy operation conditions. The proposed approach allows to identify the most cost-effective energy efficiency measures (EEMs) for building retrofits and their required investment costs. The retrofit potential benefits of the Italian office buildings stock is used as a case study to illustrate the application of the proposed analysis methodology. The results of the evaluation analysis for the Italian office building stock indicated a potential primary energy savings of 54% (i.e., 8000 GWh), when retrofitted through optimal combinations of EEMs and rooftop integrated photovoltaics. The optimal set of EEMs showed strong dependency on building typology and climate. In general, the cost-optimal combinations of EEMs and rooftop PV systems did not allow to reach net-zero energy operation conditions for any Italian office building type and climatic zone. [ABSTRACT FROM AUTHOR]

• The flexibility reserve due to long-term refurbishment strategies in buildings has been quantified. • Representative clusters are modelled to represent the current and future scenarios of the Italian building stock. • Increasing refurbishment improves the ability of the building stock to respond dynamically to price signals. • The share of the flexible demand increases as the number of dwellings with high thermal inertia increases. • From −113.5 to 45.8 GWh e can be daily shifted by activating the energy flexibility of the whole 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 GW e in 2050. While in terms of energy, the following amounts of average daily shiftable energies have been obtained: from −34.4 to + 13.6 GWh e in 2030, from −75.4 to + 16.2 GWh e in 2040 and up to −113.5 to + 45.8 GWh e in 2050, that represent around 2% of the present Italian electricity demand. [ABSTRACT FROM AUTHOR]

The concerted effort to collect earthquake damage data in Italy over the past 30 years has led to the development of an extensive database from which vulnerability predictions for the Italian building stock can be derived. A methodology to derive empirical vulnerability curves with the aforementioned data is presented herein and the resulting curves have been directly compared with mechanics-based vulnerability curves. However, it has been found that a valid comparison between the empirical and analytical vulnerability curves is not possible mainly due to a number of shortcomings in the database of surveyed buildings. A detailed discussion of the difficulties in deriving vulnerability curves from the current observed damage database is thus also presented. [ABSTRACT FROM AUTHOR]

Abstract: The objective of this work is to implement a simplified calculation procedure for building net energy need, based on a quasi-steady state model and on a monthly data set. In particular, it is intended to supply a formulation of the dynamic parameters and to adapt them to Italian climatic, typological, constructive and user data. The method was validated by determining the numerical correlations of the gain/loss utilization factor, through a comparison with a detailed building energy simulation software (EnergyPlus). The simulation was run on some test rooms defined by CEN (European Committee for Standardization) and on some real buildings that are representative of the Italian building stock, assuming weather data from different Italian locations (Torino, Roma, Palermo). The work shows that the accuracy of results is greatly affected by nonlinearities in the determination of the heat transfer and that the dynamic parameters are sensitive to some building features which are not taken into account in the CEN correlations. [Copyright &y& Elsevier]

The Energy Performance of Buildings Directive 2018/844/EU introduced the smart readiness indicator (SRI) to provide a framework to evaluate and promote building smartness in Europe. In order to establish a methodological framework for the SRI calculation, two technical studies were launched, at the end of which a consolidated methodology to calculate the SRI of a building basing on a flexible and modular multicriteria assessment has been proposed. In this paper the authors applied the above-mentioned methodology to estimate the SRI of the Italian residential building stock in different scenarios. To this end, eight "smart building typologies", representative of the Italian residential building stock, have been identified. For each smart building typology, the SRI was calculated in three scenarios: (a) base scenario (building stock as it is); (b) an "energy scenario" (simple energy retrofit) and (c) a "smart energy scenario" (energy retrofit from a smart perspective). It was therefore possible to estimate a national average SRI value of 5.0%, 15.7%, and 27.5% in the three above defined scenarios, respectively. [ABSTRACT FROM AUTHOR]