CO₂ emissions need to be reduced drastically to fight climate change and minimise the further increase of average global temperatures. The decarbonisation of the energy system aims at reducing CO₂ emissions and is thus urgently needed. This transition is facilitated by inter alia switching to renewable energy sources and more efficient technologies. In the past, the energy transition has mostly focused on supply-side measures. However, at least since the publication of the 6th IPCC assessment report, demand-side measures have gained attention. Thereby, the roles individuals play in achieving this transition is recognised as important. This Special Feature is dedicated to exploring the roles of individuals within the energy transition. The nine thematically featured articles provide insights on this topic using different foci and angles, such as the information to guide individuals' behaviour, the influence of media in framing roles, and technology acceptance. To contextualise and synthesise these diverse contributions, this editorial introduction outlines three different, complementary clusters of roles: technology adoption, lifestyle choices, and political action. By theorising users as participants in transitions through diverse practices, we widen the basis for future research to address and incorporate the roles users play in engaging with and shaping these transitions.

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Technological innovations are a key part of the energy transition. However, the social sphere as a force to facilitate the energy transition must not be neglected. While the socio-technical transition theory provides a framework to connect the technological with the social sphere, the role of the individuals within the transition process remains limited (Upham et al. 2020). Individuals are reduced to the role of consumers and technology users (Avelino and Wittmayer 2016; Nijhof et al. 2022), and the social sphere is subject to change rather than an instigator of it (Kivimaa et al. 2021). Potentially alternative concepts need to be developed and employed to understand the role of the individual within the energy transition. With a focus on the energy transition, this special feature is dedicated to compiling scientific contributions that provide insights into how the individual is embedded within the larger system and how individuals are facilitating the energy transition. Thus, the role of the individual is not limited to the consumer or the user of technology. Rather special feature contributions identify how individuals are agents of change within the energy transition. Furthermore, the seed of change is not limited to technological or market innovations but includes, for example, social innovations contributing to the energy transition. Scientific articles will also provide insights into how individuals are embedded within the larger system. To shed fresh light on interconnections and the role of individuals in the energy transition, alternative approaches to socio-technical or socio-economic transition theory are welcomed.@en

Community-based energy systems are gaining traction among policymakers and practitioners as promising models for implementing a low-carbon energy transition. As a result, there has been a proliferation of concepts in the scientific literature, such as community energy, energy communities, community solar, and community wind. However, what scholars mean by “community” in these contexts is often unclear and inconsistent. This paper provides further conceptual clarity in the field by analyzing how the term of community is conceptualized in the scholarly literature on energy systems, through a systematic review of 405 articles. We combine an author keyword network analysis of this corpus with an in-depth analysis of 183 definitions extracted from these articles and systematically coded across three dimensions: meanings, activities and objectives of communities. Our findings show that the meanings attached to the notion of community and the alleged objectives pursued by communities vary substantially across concepts and over time. In particular, there has been a shift away from a notion of community understood as a process that emphasizes participatory aspects toward a notion of community primarily referring to a place. Furthermore, there is a growing focus on communities' economic objectives rather than their social or political goals. These findings suggest a weakening of scholars’ attention to “transformative” notions of community emphasizing collective and grassroots processes of participation in energy transitions, to the benefit of “instrumental” notions. This trend runs the risk of placing the sole emphasis on the market value of communities, thereby diluting their distinctiveness from more commercial actors.

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Recent developments in concrete technology with high potential include ultra high performance concrete and self-compacting fibre reinforced concrete, which have a flowable consistency and can transport relatively high fibre dosages. Flowability is achieved by adopted mix design and both the mix design and flow affect the distribution and orientation of the fibres, which affect the post-cracking behaviour and accordingly the structural performance. With new materials also come new manufacturing and design approaches. The prediction of fibre orientation with computational fluid dynamics (CFD) simulations can be an important instrument to predict, understand and influence fibre orientation. With better understanding the mix design and casting process can be optimized.

This paper reports about a study executed to determine the applicability of the software package Autodesk Moldflow for fluid dynamics simulations of flowable fibre concrete. After a discussion of relevant literature, two reference cases address stretching and shearing flow conditions in a qualitative and quantitative way. Concrete was modelled as an incompressible Bingham material with addition of a fibre orientation model that was developed by Folgar and Tucker. A third case, a square panel, was used as a reference and structural element for flow simulations. Parameters varied were among others rotary diffusion, wall-slip and duration of casting.@en