The small-scale prosumers’ decentralized cooperation and aggregation in energy communities are essential to increase renewable energy penetration and to ensure a successful energy transition. Despite their potential small-scale prosumers are not motivated to participate in local energy value chains due to a lack of trust and decentralized cooperation models for capturing local sustainability preferences, most innovation efforts are focused on financial incentives that are anyway very low. In this paper, we propose a solution for prosumers’ decentralized coordination using a cooperative game on top of a blockchain overlay by considering their complementary energy-related features and flexibility for self-sufficient energy communities. We define a governance model based on cooperative games and blockchain-sharing mechanisms reinforce the prosumers’ trust to support the decentralized self-organization in coalitions to balance the renewable generation and demand. Self-enforcing smart contracts are used for the blockchain integration of the governance model to allow the decentralized creation and management of prosumers’ coalitions for optimized payoff distribution towards self-sufficiency and using tokens capturing the beyond-financial community level exchanges. The evaluation results show our solution’s effectiveness in enabling prosumers to cooperate and create self-sufficient coalitions in a decentralized fashion with low gas consumption and transactional time overhead.