Renewable Energy, including solar, wind, hydro, biofuels and others, is at the center of the transition to a less carbon-intensive and more sustainable energy system. Renewables have grown rapidly in recent years at both international and national level, driven by policy support and sharp cost reductions for solar photovoltaics and wind power in particular. The electricity sector remains the brightest spot for renewables with the strong growth of solar photovoltaics and wind in recent years, building on the already significant contribution of hydropower. But electricity accounts for only a fifth of global energy consumption, and the role of renewables in the transportation and heating sectors remains critical to the energy transition. Exploitation of renewables to generate energy and produce electricity is simultaneously suggested for the last couple of decades as a viable alternative in mitigating climate change. Energy, where renewable energy is a branch, is generally regulated and governed domestically and so, international legal regime is still evolving in this regard. In this backdrop, this paper aims to introduce reformative prospects of the alternative route of usage of renewable sources as massive form of energy efficiency. Prospects and challenges in their promotion that may help to mitigate the adverse effects of climate change are to be analyzed. Relevant international and law provisions will be thoroughly exposed and evaluated, performances of the relevant regional and international organizations active in this sector are highlighted and some of the disputes in this area considered in international forums are duly addressed.