This study explores the implications of technology availability constraints on the decarbonisation pathways of the EU power sector, drawing on scenario results from five European energy supply models: MEESA, LIMES, ENERTILE, ACSG, and OSeMBE. The analysis evaluates how limiting the deployment of key low-carbon generation technologies, namely carbon capture and storage (CCS), nuclear power, bioenergy, solar photovoltaics, and wind energy, affects the electricity generation mix, emissions reduction, investment needs, and power system costs by 2030 and 2050. Results within the model ensemble indicate that variable renewable energy sources (VRE), wind and solar, are indispensable for deep decarbonisation. Constraints on solar or wind power substantially increase electricity generation costs and require major shifts in technology portfolios, often resulting in greater reliance on remaining renewable options or fossil fuel generation with CCS. The unavailability of CCS leads to higher system emissions and increased investment in renewables and storage. In contrast, removing nuclear or bioenergy has a more moderate impact, though some regional effects are significant. All models show that achieving ambitious emission reductions in the power sector remains technically feasible under individual technology constraints, but the mitigation effort shifts across generation technologies, and system costs rise considerably in low VRE futures. Policy implications include the need for robust support for wind and solar deployment, cross-border system integration, flexible technologies, and backup capacity. The findings underscore the value of a diversified technology portfolio, strategic infrastructure investments, and EU-level coordination to preserve cost efficiency and ensure stable power system performance under uncertainty in future technology availability.

A fast-paced policy context is characteristic of energy and climate research, which strives to develop solutions to wicked problems such as climate change. Funding agencies in the European Union recognize the importance of linking research and policy in climate and energy research. This calls for an increased understanding of how stakeholder engagement can effectively be used to co-design research questions that include stakeholders' concerns. This paper reviews the current literature on stakeholder engagement, from which we create a set of criteria. These are used to critically assess recent and relevant papers on stakeholder engagement in climate and energy projects. We obtained the papers from a scoping review of stakeholder engagement through workshops in EU climate and energy research. With insights from the literature and current EU climate and energy projects, we developed a workshop programme for stakeholder engagement. This programme was applied to the European Climate and Energy Modelling Forum project, aiming to co-design the most pressing and urgent research questions according to European stakeholders. The outcomes include 82 co-designed and ranked research questions for nine specific climate and energy research themes. Findings from the scoping review indicate that papers rarely define the term 'stakeholder'. Additionally, the concepts of co-creation, co-design, and co-production are used interchangeably and often without definition. We propose that workshop planners use stakeholder identification and selection methods from the broader stakeholder engagement literature.

: The understanding of the transboundary impact of Climate Change on hydropower is not well-established in the literature, where few studies take a system perspective to understand the relative roles of different technological solutions for coordinated water and energy management. This study contributes to addressing this gap by introducing an open-source, long-term, technologically-detailed water and energy resources cost-minimisation model for the Drin River Basin, built in OSeMOSYS. The analysis shows that climate change results in a 15-52% annual decline in hydro generation from the basin by mid-century. Albania needs to triple its investments in solar and wind to mitigate the risk of climate change. Changing the operational rules of hydropower plants has a minor impact on the electricity supply. However, it can spare significant storage volume for flood control.

Abstract Worldwide, cities are implementing circular economy (CE) strategies to reduce the resources they consume and their environmental impact. However, the evidence of the intended and unintended social consequences of the transition to “circular cities” is scattered. The lack of a coherent overview of the evidence on the subject can hinder effective decision-making in policy and practice. This study examines the extent to which the current literature addresses the social impacts that a transition to a CE produces in cities. We used a methodological approach related to systematic mapping to collate the evidence published over the past decade globally. The study finds that social impacts have rarely been considered in studies of circular cities, and where they have been discussed, the scope has been quite limited, only covering employment (mostly of informal sector workers) and governance practices. This scoping review highlights the need to further analyse and integrate social impact considerations into decision-making connected to transitions towards circular cities.