Impact of local capacity investments in energy communities on national decarbonization pathways

This paper investigates the impact of local capacity investments in energy communities on national decarbonization pathways. This study uses a long-term energy system model (POLES), enhanced by an energy system modeling framework (Backbone), to optimize the national transmission and distribution grids. This model is further enhanced to account for local capacity investments in energy communities. The results show that energy communities could accelerate the integration of renewables and alleviate distribution grid constraints by more closely aligning production and demand geographically. However, overly extensive integration of energy communities also has drawbacks: they alter the residual load that the main system must supply, but not uniformly. This means that the peak demand remains high, whereas demand could be divided by two during low-demand hours. This could lead to suboptimal use of nuclear plants, which are required to meet peak demand but must reduce their production, leading to lower revenues during midday hours. Moreover, the deployment of energy communities requires control and exchanges between power system actors, as large-scale integration of uncoordinated local investments results in higher capacity requirements, particularly for solar (+100%) and batteries (+130%). A moderate development of energy communities could nevertheless be cost-effective, especially if community members align their demand with the renewable energy production.