Leading RRI researchers and practitioners, together with policymakers and stakeholder organisations, discussed the state-of-the-art and future perspectives for RRI at the ‘Pathways to Transformation’ conference in June 2019, an event which was extended beyond Brussels, for instance by ca. 330 original tweets and ca. 840 retweets from ca. 160 unique accounts. In the conference, many participants expressed their concern about an uncertain future for RRI in the EC. As a result, numerous large-scale EU-funded RRI projects signed a Joint Declaration, urging the European Commission to make RRI a key objective of the upcoming framework programme, Horizon Europe – a plea to both mainstream the approach across the programme and provide specific resources for strengthening the RRI knowledge base. As the Horizon Europe programme is being forged, it is timely to present the Declaration for a broader audience.

The concept of intermediate band solar cell (IBSC) is, apparently, simple to grasp. However, since the idea was proposed, our understanding has improved and some concepts can now be explained more clearly than when the concept was initially introduced. Clarifying these concepts is important, even if they are well known for the advanced researcher, so that research efforts can be driven in the right direction from the start. The six pieces of this work are: Does a miniband need to be formed when the IBSC is implemented with quantum dots? What are the problems for each of the main practical approaches that exist today? What are the simplest experimental techniques to demonstrate whether an IBSC is working as such or not? What is the issue with the absorption coefficient overlap and the Mott’s transition? What would the best system be, if any?

The concept of "intermediate band solar cell" (IBSC) is, apparently, simple to grasp. However, since the idea was \ud proposed, our understanding has improved and we feel now that we can explain better some concepts than we initially \ud introduced. Clarifying these concepts is important, even if they are well-known for the advanced researcher, so that \ud efforts can be driven in the right direction from start. The six pieces of this work are: Does a miniband need to be formed when the IBSC is implemented with quantum dots?; What are the problems of each of the main practical approaches that exist today? What are the simplest experimental techniques to demonstrate whether an IBSC is working as such or not? What is the issue with the absorption coefficient overlap? and Mott's transition? What the best system would be, if any

The use of photovoltaic (PV) systems for powering heat pumps (HP) leads to an economic, energy efficient and environmentally friendly alternative for heating and cooling generation. A technical solution developed by the authors permits stand-alone configurations to operate without batteries, mitigating up to 75% of the solar power fluctuations resulting from cloud-passing. Once its technical feasibility has been demonstrated, the economic potential of this innovative solution should be assessed (avoiding a battery system is a significant advantage). This paper presents a comparative economic assessment of this autonomous (AU) solution and a self-consumption (SC) solution, that would substitute a grid-powered HP system for the space heating and cooling of two livestock farms located in Spain. Results show that PV-HP systems are economically feasible regardless of the technical solution: the Profitability Index (PI) is in the 2.23–2.97 €/€ range, the Internal Rate of Return (IRR) is in the 8.1–10.9% range, the Payback Period (PBP) is in the 9.2–11 years range and the savings in terms of the Levelized Cost of Energy (LCOE) are in the 57–70% range. The AU solution offers a higher economic profitability, because it permits larger savings in the electricity bill. The SC solution presents lower LCOEs because of its greater electricity production.

With the emergence of energy communities, this paper explores their operationalization as a tool with which to create large and stable citizen science and education hubs focused on energy, where citizens can have the chance of exploring a first-hand approach to the energy transition. We present the rationale behind an energy community, whose purpose is to generate systemic and transformative changes in local environments. The concept of an energy community is used to reflect the legally recognized union of citizens, which is much stronger than any associative mechanism yet without such a structure. While the latter’s actions and interests align with those of energy communities, its operation mode differs in terms of the priority assigned to each of them. The developed model has been submitted for feedback to three European university communities. The feedback received has highlighted the acceptability of the model and encouraged us to move forward with its implementation. Approximately 90% of the participants in the study would partake in this type of energy community in very diverse ways, which shows the capacity of the model for inclusiveness and universal access to energy experiences. The barriers and drivers expressed by the participants of the study were analyzed to identify the aspects that foster or prevent citizens’ participation. This approach will allow us to define a more responsible action plan when turning these models into reality.