*1.2. The Significance of Urban Building Energy Modelling*

Energy modelling on the building scale is a mature and complete field, providing reliable decision-support for building energy design [20]. Urban building energy modelling (UBEM) seeks to upscale this field to better understand of new and existing neighbourhoods and assess urban energy systems described by Keirstead et al. [21] as "formal systems that represents the combined processes of acquiring and using energy to satisfy the energy service demands of a given urban area". While research in UBEM has surged [21], it is still yet considered "half-baked" [20] and has tremendous potential.

Sola et al. [22] describes Urban-scale Building Energy Modelling (UBEM) as part of Urban Scale Energy Modelling (USEM). According to them and Allegrini et al. [23] USEM is capable of modelling not just building related, but multisectoral energy flows including grid, mobility, microclimate, therefore accurately model district urban energy systems. Part of this is UBEM which can simulate energy demand of the building stock by combining energy models of standalone buildings into a summarized district-scale model. According to another definition form Reinhart and Davila [24] UBEM is a tool able to simulate energy demand on a city block, district, entire city or even on a bigger scale. Goy and Finn [25] differentiate small- and large-scale energy modelling at five buildings/households in their review [25]. On small scale building energy modelling is where the aim is to obtain data for internal thermal control, or thermal loads, however at large scale energy modelling aim is to predict performance indicators like building energy consumption, CO2 emission and new policy impacts [25]. It is a necessity when considering place-based ECs to have information about the building energy demand, since according to [3] these type of ECs gather on spatial basis and are based on shared ownership, typically in blocks, flats, building blocks or districts. While USEM, as described above vaguely refers to multisectoral energy flows in urban context and examples mentioned in [22,23] also incorporate tools which do not take building energy demand into consideration, for the purpose of this study we considered USEM as tools which can model building energy demand, and other energy flows as well.

UBEM's significance is multifaceted. Simulations promote market competitiveness, which in a liberalized market is strongly tied to the success of a new energy paradigm [26]. Urban scale simulations can provide a better understanding of the optimum combination of building and area specific measures and interchange of energy options [27]. Through benchmarking they can provide transparency [28] in energy efficiency markets, therefore growing trust and increasing investment appetite [29]. Analysing different scenarios can contribute in the development of consumption awareness and therefore raise consciousness for the sustainable environment [27], also capable of helping energy policy formulation since it frequently leans on the evaluation of overall building performance [30].

#### *1.3. Gap in the Research Fields*

The potential of energy communities remains theoretical, and communities themselves exist in niches of a few industrialized, developed nations [1]. Studies setting up the research agenda for energy communities point out an empirical gap in understanding "who the project is for [...] and how do they benefit" [6]. This is a common theme for energy communities, both their design and their research seem ill-equipped to fully map the distributional aspects of the multiple impacts of projects [6]. This is partly due to the convention to take buildings as isolated units of investigation for planning energy [31]. The influence of urban surroundings on their energy performance has not been properly incorporated as well as the interdependencies that may occur amongst them [31].

This means both community energy research and practice lack the tools to incorporate emergent properties on the urban scale such as microclimate, renewable potential or load-curve differences [32]. Regarding practice, this results in major barriers to progress community energy projects, because it means uncertainties are high, participant and supporting networks cannot be established on a performance-basis, regulations, policymakers and financers are more difficult to be convinced [2]. Regarding research, this is evident in calls for more empirical knowledge on the changes community energy delivers [6]. This means that the gap in research—lack of evidence in the distributional multiple impacts of energy communities—can be traced to missing means to produce such evidence, which would also be a trigger for the practice of energy communities. Hypothetically, urban-scale energy modelling could be such a tool, but the two research fields have not yet met, there are no reviews on the potential of UBEM in advancing ECs (see Section 2). Studies of UBEM are technically focused, lacking application-oriented classifications to assess potential in energy communities, while studies on EC do not explore technological triggers to overcome barriers (see Section 2).
