Renewable energy provides an answer to the most pressing socioeconomic challenges that governments face today, in particular the effects of climate change. Although efforts have been made throughout the world, it is necessary that investment in renewable energy is further increased if it is to have a marked impact on the reduction of carbon dioxide (CO2). The lack of national investment is inevitably going to trigger the inflow of foreign investment which is subject to 'performance requirements' which are regulated by a number of international norms. The chapter reviews all the rules currently applicable and stresses their differences to provide a typology of existing prohibitions. The analysis is further refined by a comprehensive review of the case law (both decided by trade and investment tribunals) to identify the type of requirements which have been implemented on renewable energies. It also explains and anticipates the role of the most-favoured national (MFN) treatment in the context of bilateral treaties in a manner hitherto unexplored. In doing so, this Article provides a comprehensive analysis of the 'performance requirements' in international treaties with a view to assessing their impact on the further development of renewable energies.