Shared energy in renewable energy communities: The benefits of east- and west-facing rooftop photovoltaic installations

Renewable energy communities (RECs) offer a promising perspective for decarbonizing the building sector. This is accomplished by enhancing the uptake, among others, of citizen-owned rooftop photovoltaic systems. A key challenge lies in ensuring that photovoltaic generation matches the needs of community members, i.e. maximizing shared energy index. Indeed, the shared energy depends on the consumption habits of individual members and the rooftop characteristics, such as orientation and inclination of available pitches, which influence the production curve. Therefore, clear guidelines on which roof pitches are most suitable for PV generation within RECs might be helpful during the design of such communities. In this paper, we investigate the optimal orientations and tilt angles for PV systems in REC design. We conducted a robust Monte Carlo simulation of an energy community comprising 60 users, 30 of which are equipped with rooftop PV systems for a total of 150 kWp installed. Our analysis revealed that pitches with West and East offer comparable, if not better, shared energy values than those South-facing, consequently mitigating peak power dispatched to the grid. Besides, shared energy remains quite constant across various tilt angles. These findings suggest that buildings with non-South-facing roofs should not be overlooked, but embraced in the design of renewable energy communities as they can contribute significantly to shared energy.