INTRODUCTION. The gradual reorientation of the global energy system from carbon energy to renewables (solar, wind, tidal energy etc.) aimed at reducing human-caused environmental changes raises the issue of international cooperation in this area. Moreover, energy security issues being closely connected with the ones of national security, the international agenda on renewable energy sources is highly influenced by the geopolitical situation, too. The author analyzes the legal mechanisms for cooperation regarding renewable energy between the Member States of the European Union, an international organization that, aiming to reduce its dependence on carbon energy resources from Russia, focuses, among other things, on developing the most effective ways of such cooperation. The author defends the thesis that a legal assessment of such mechanisms' advantages and disadvantages will help assess the potential for their conceptual adaptation within the platforms where Russia's regional cooperation is implemented (i. e. the Eurasian Economic Union and the Arctic Council). MATERIALS AND METHODS. In the course of the study, the author used sources of EU law (regulations, directives) regulating cooperation between the Member States in the field of renewable energy, international agreements concluded in accordance therewith, as well as studies of foreign scientific works on the issues of implementation of the relevant rules. Furthermore,assessing the possibilities of using the relevant mechanisms in regional organizations of which Russia is a member, the author uses international treaties, declarations and decisions of bodies of such internationalorganizations as the CIS, the EAEU, and the Arctic Council. The methodological basis of the study was formed by general scientific techniques (analysis, synthesis, induction, deduction, comparison, classification, systematization, forecasting) and private scientific techniques (formal legal and comparative legal method). RESEARCH RESULTS. The article provides a comprehensive legal analysis of the three main mechanisms for cooperation between EU Member States (statistical transfers, joint projects and joint support schemes). Several issues were identified that reduce their effectiveness, including uncertainty regarding the extension of the deadlines for their application after 2030, the lack of sanctions for non-compliance with mandatory targets provided for by the relevant directives, sovereignty restrictions and, in this regard, insufficient motivation for their application. It is noted that the main incentive for using the outlined mechanisms is the Member States' binding statistical goals in renewable energy use in their national energy mix. Nevertheless, despite the above issues, the author points out that the ideas of the EU legal regulation at present, after its detailed study, can be attributed to the "best practices" of international legal regulation of the use of renewable energy. In this regard, the conceptual foundations of the cooperation mechanisms between the EU Member States can be used in developing interaction within the framework of the Eurasian Economic Union and the Arctic Council (as an organization within which key decisions are made regarding the environmental security of the Arctic region). DISCUSSION AND CONCLUSIONS. Within the research framework, the author analyzed the EU directives and regulations governing the procedures for cooperation between its Member States regarding renewable energy and the practice of implementing such procedures. These interaction mechanisms encouraging states to achieve their own binding goals in renewable energy use seem optimal for developing international legal measures to support RES in organizations and forums with the participation of Russia. The author concludes that one of the most effective areas of such cooperation could be the development of appropriate mechanisms within the framework of the EAEU. This organization aims to integrate the market systems of the member states. Therefore, a limited circle of its members could make it possible to avoid many political contradictions that have already arisen in the negotiations on similar mechanisms in the CIS. In addition, given the strategic importance of the Arctic region for Russia, the ideas of these mechanisms could also be considered in the Arctic Council. Although, at the moment, the work of this international forum has been suspended as a reaction of other Arctic states to Russia's actions regarding the Ukrainian crisis, it does not seem to be a viable option to solve the issues of preserving the ecosystem of the Arctic.