This research raises the possibility for households in energy poverty to participate in shared photovoltaic systems in renewable energy communities (REC) to reduce their energy costs, with investment costs covered by public institutions. It begins by evaluating the current solution for vulnerable households, which relies on public subsidies to lower energy costs without addressing root causes or improving environmental impacts. The study compares traditional subsidies with REC participation for vulnerable households. By simulating a REC composed of such households, the results indicate that REC participation is more cost-effective for public institutions than energy subsidies. At the economically optimal size of 31 kWp, the cost of subsidies decreases by 58,000 €, a 50% reduction, with household savings increasing by 6%. At 58 kWp, the need for additional support checks is eliminated, increasing household savings by 65% but with a lower NPV of 22,500 €. The largest viable system, 75 kWp, increases average household savings by 82%. This approach also leads to a net reduction in GHG emissions, engaging previously excluded households in the energy transition.

This research raises the possibility for households in energy poverty to participate in energy communities to alleviate their energy costs, having their investment costs paid by public institutions. The study starts from the current solution for vulnerable households based on public subsidies to reduce energy costs, which neither addresses the problem's causes nor improves the residential energy systems' environmental profile. It compares the business-as-usual solution, energy checks, with the participation of vulnerable households in energy communities. We simulate a renewable energy community composed of vulnerable households to calculate the usefulness of this solution. he chosen vulnerable households are doubly vulnerable because they are older people experiencing social isolation and loneliness. The results show that participating in energy communities can be a better economic option for public institutions than paying energy subsidies. Moreover, most households increase their savings, and in all cases, it results in a net reduction of GHG emissions, engaging households unable to participate in their current situation in the energy transition.

This research aims to diagnose the energy performance of buildings in València and identify areas where energy efficiency can be improved. The energy performance results of all 129,487 EPCs in the city were mapped and compared to socioeconomic variables to gain insights into the reasons behind the results. The study reveals that the city's building stock has poor energy performance, attributed to the lack of building standards during the city's expansion in the 1960s and 1970s. The worst energy performances are observed in the peripheral districts, particularly in the city's northern half, where low-income and low-renting rates are common, resulting in reduced investment capacity for individuals to retrofit their homes. To promote quick dissemination of measures to retrofit households, they must be adequate, economical, and replicable, avoiding social, administrative, and economic barriers. The study highlights the importance of EPCs as an objective tool to diagnose the energy efficiency of a city's building stock. Policymakers can use the findings to identify areas that require improvements and evaluate the appropriate actions to improve the building stock's energy performance. This study presents significant potential to reduce buildings’ energy demand and achieve climate goals through EPCs.