Substantial research effort has been devoted on the importance of integrating energy into spatial planning and even more to embed their synergy in the regional value and production/consumption chains, in order to develop less vulnerable to failure and to societal resistance energy projects. Inspired by these findings, a methodological approach for holistic energy planning on a regional/local level was developed under the INTENSSS-PA project (HORIZON2020 Programme). The core of this methodology lies on the Regional Living Lab (RLL) approach, including multiple aspects such as the development of spatial concepts, new co-creating strategies, business cases, societal alliances, and institutional changes and formats. The objective of this paper is to develop and operationalize a methodological framework for evaluating: (i) the overall performance of the proposed Integrated Sustainable Energy Planning methodology, (ii) the performance of the energy plan, and (iii) the performance of the INTENSSS-PA RLL as an environment for integrated sustainable energy planning and the performance of the INTENSSS-PA RLLs in relation to the LL’s essentials. The evaluation methodology is applied on the case study of the RLL established by the Junta de Castilla y Leon in Spain, showing the related performance results.