This paper presents a modular and generalizable framework for assessing the integrated energy, economic, and environmental performance of renewablebased Energy Communities combining photovoltaic generation and battery energy storage systems (BESS). The framework includes four analytical modules — energy, economic, environmental, and break-even analysis — each designed to quantify specific Key Performance Indicators related to efficiency, profitability, and sustainability. The proposed approach enables the evaluation of how battery integration impacts local self-consumption, energy autonomy, and CO2 emissions, while identifying the maximum sustainable battery cost that ensures economic feasibility for end users. The methodology is applied to different scenarios, showing that the inclusion of BESS enhances energy self-sufficiency by up to 56% and reduces annual CO2 emissions by more than 50 tons for a 1 MW capacity system. Although the payback period and ROI remain constant across scenarios — by design, as the maximum sustainable battery cost is determined for a fixed payback target — annual savings increase significantly, demonstrating that storage becomes economically viable as market costs decline. The framework provides policymakers and stakeholders with a transparent decision-support tool to evaluate investment feasibility and to design incentive mechanisms for a just and economically sustainable energy transition