From allocation to trading: A four-stage framework for Portuguese self-consumption communities

Portuguese collective self-consumption communities share locally generated electricity through a regulated allocation layer. This paper asks how much additional value can be captured by a subsequent local trading layer once that allocation has been applied, and who receives it. A four-stage framework is proposed combining behind-the-meter self-dispatch, regulated allocation, residual trading, and settlement. Six fixed, consumption-based, hierarchical, and dynamic allocation mechanisms relevant to the Portuguese setting are compared. The analysis examines how savings are distributed among members and applies a budget-balanced adjustment to prevent participants from ending up worse off than under the baseline case. The framework is tested on a Portuguese cooperative using measured fifteen-minute demand from ten households, simulated solar generation from local weather data, and scenarios with and without energy storage. More adaptive mechanisms can absorb all locally matchable energy before trading occurs, whereas less adaptive rules leave residual opportunities for subsequent exchange. In the studied hybrid configurations, however, the final community bill is the same because residual trading clears the matchable energy left by the upstream allocation. The allocation choice therefore affects where the economic value is realized and how it is distributed among members, with adaptive mechanisms producing less even benefit distributions. Without storage, community sharing and trading reduce the bill by 7.0%. With storage, the additional community-level benefit falls substantially because it captures most of the available solar value beforehand. Communities already using fixed shares can therefore recover the residual economic opportunity through an additional trading layer without changing their existing allocation structure.