Second-Level Renewable Energy Cooperatives for Closing the Governance-Economics-Decision Support Gap: A Systematic Review and MCDM/A Governance Model

Renewable energy communities (RECs) are legally recognised instruments of decentralised energy transition, but their scaling remains limited by a separation between governance design, economic appraisal, and multi-criteria decision analysis (MCDM/A). This systematic review applies a conservative explicit-reporting coupling diagnostic to 322 REC studies from a 2014–2026 corpus. The diagnostic identifies 267 unilateral studies (82.9%), 55 bilateral studies (17.1%), and no study satisfying the strict trilateral criterion at the title/abstract/metadata reporting threshold. A loosened-keyword sensitivity test identified two weak trilateral candidates, but the manual construct-validity audit did not support reclassifying them as strong trilateral studies. The result is therefore interpreted as a conditional and conservative signal of limited visible integration, not as proof that no body-text-level integration exists. The paper argues that the observed separation is not only methodological but also institutional. It therefore proposes second-level renewable energy cooperatives as federated decision-support entities that pool data stewardship, distributional economic appraisal, stakeholder-weighted MCDM/A, and auditable cooperative voting packages while preserving local REC control. The model converts the explicit-reporting gap into a testable governance architecture for REC scaling.