The transition to low-carbon energy systems is a complex process that implies radical technological changes, greenhouse gas emission reductions, and benefits to the local economies yet, also significant investment, a need for capacity building, strengthening supply chains and supporting legal frameworks. Consequently, the choice of renewable energy technologies should be based on a comprehensive assessment addressing the different dimensions that are affected. Clean energy technologies are traditionally evaluated on the basis of their techno-economic performance. Such an approach penalises emerging energy technologies that are generally more capital-intensive given their innovation requirement and the lack of support mechanisms facilitating their industrial roll-out. In this paper, a multi-criteria evaluation framework is proposed encompassing three important broad dimensions: techno-economics, environment and socio-economics. The applicability and flexibility of the proposed evaluation framework are demonstrated on different case studies. First, the hypothetical deployment of a floating offshore wind farm both in Scotland and Portugal is evaluated. Later, the proposed framework is used to evaluate the deployments of wave energy devices in the same two locations. The results show that this multi-criteria approach provides a more holistic overview of the performance and implications of renewable energy technologies, particularly emerging ones, and can better support decision- and policy-making in the medium- and long-term. Furthermore, the framework can be used by researchers, investors, developers and/or analysts to assess energy planning alternatives.