The research focuses on adapting production expansion planning for local energy communities composed of small and medium-sized enterprises (SMEs) with specific market designs. Renewable Energy Communities (RECs) enable consumers and prosumers connected to the public electricity distribution network to exchange energy locally, bypassing the traditional wholesale market. RECs promote local investment in renewable energy and improve self-consumption and self-sufficiency through resource mutualization and coordinated investments. The large-scale implementation of RECs impacts technical, economic, regulatory, and legal aspects, which require accurate quantification. This project aims to develop innovative techniques for aggregating time series data for production and consumption models of community members, informed by optimal planning model results, rather than standard ex-ante clustering measures.