Energy Communities are increasingly recognised as important actors in the European energy transition, with the potential to support renewable energy uptake, local value creation, and more active citizen participation in energy systems. Despite the progressive strengthening of the European framework for Renewable Energy Communities and Citizen Energy Communities, their practical implementation remains uneven across Member States. In many cases, barriers do not arise solely from the absence of legal recognition, but from the way regulatory conditions are translated into operational rules, administrative procedures, and participation requirements.

This paper proposes a user-centred approach to identifying regulatory barriers affecting EC development in Europe. Building on work developed within the COMMUNITAS project, the study uses 23 User Stories collected through a participatory workshop and analyses them through a process of qualitative coding and thematic clustering. The results reveal four main barrier domains: (i) legal recognition and definitions of energy communities, (ii) energy-sharing rules and flexibility constraints, (iii) administrative, procedural and financial barriers, and (iv) data access, digitalisation and consumer protection. The findings show that barriers are multidimensional and strongly shaped by stakeholder experience, often emerging at the intersection of regulation, institutional practice, and implementation conditions. Obtained results demonstrate that User Stories can provide a valuable methodological complement to conventional regulatory analysis by capturing how enabling frameworks are perceived and experienced by actors engaged in the creation and operation of Energy Communities.

The impacts of climate change are intensifying the need for a transition towards renewable energy sources. However, the intermittency of renewable generation, combined with rising energy demand and the electrification of key sectors, poses significant challenges to grid stability. Load flexibility emerges as a promising solution to support the integration of renewable energy sources. Therefore, a Genetic Algorithmbased Demand Response tool was developed and integrated with a Non-Intrusive Load Monitoring framework. The tool identifies and suggests the optimal operating times for userdependent flexible household appliances, aiming to reduce energy costs. In this paper, the potential of the tool is assessed by analyzing the influence of external factors, namely user acceptability and the presence of photovoltaic systems, on the effective exploitation of residential load flexibility. The results show that the tool achieves meaningful savings even without local generation, although its performance is strongly dependent on the amount and usage frequency of flexible loads available in each household.

Legislative differences between Portugal and Spain regarding energy-sharing mechanisms within energy communities are investigated. In Spain, an ex-ante allocation method is mandated, assigning energy shares before consumption occurs, while Portuguese legislation permits an ex-post approach, allowing allocations after real consumption is measured. To assess these contrasting frameworks, real consumption and generation data from an energy community located in Crevillent, Spain, is considered. This study applies the conditions permitted in each country to this dataset to test each energy-sharing methodology, enabling a comparative analysis of their impacts. Under the ex‑ante framework, collective self‑consumption levels remain limited, not surpassing 70%, even when variable sharing coefficients are applied. In contrast, the ex‑post allocation permitted by the Portuguese regulation increased collective self‑consumption to above 90%, revealing the extent to which regulatory constraints affect key performance indicators of energy communities, such as energy-sharing efficiency and utilization of local generation.