Impact of grid tariff design and prosumer flexibility investments on peak load reduction — Participation in multiple renewable energy communities

The increasing electrification of energy systems, combined with inelastic and uncontrolled consumer demand, leads to an increasing peak–base load spread. This challenge requires a grid tariff adjustment to incentivize investments in flexibility, thereby enabling demand response to smoothen the overall load profile. Renewable energy communities offer some flexibility potential. However, the current grid tariff design creates disincentives for grid-friendly behavior. The core objective of this work is to model the impact of different grid tariffs on investment in flexibility and peak load reduction within multiple renewable energy community participation. A mixed-integer linear programming model is developed, providing a unified framework that integrates grid tariff design, multiple renewable energy community participation, and investment in flexible technologies. The results of an Austrian case study indicate that multiple participation and grid tariffs based on a power-component with a linear cost function result in increased flexibility reinvestment of up to 51%, compared to single participation in the same tariff design. Power tariffs can reduce maximum peak load by up to 65%, while peak frequency changes vary widely. To support grid-friendly behavior, we recommend that multiple participation should be paired with a power-based grid tariff, incentivizing higher flexibility reinvestment and peak load reductions.