The world's energy demand is growing and conventional sources are diminishing. Sustainable/renewable energy sources are gaining possibilities to come up with solutions to the long standing energy crisis, environmental problems, economic development and quality of life. By adopting renewable technologies in developing countries like India, effective steps are being taken towards clean mechanism and fortifying more sustainable future. From the past three decades there has been a strenuous pursuit to development, demonstration, application, production and research of renewable/sustainable technologies for use in distinct sectors. These efforts led to substantial improvement in renewable power generation. However, energy demand also increases largely in higher proportion to the production. It is observed that the current energy requirement is more than 1162 million units (MU) and the availability is 1138 MU leaving a shortage of 24 MU approximately. Hence, this paper focuses on discovering further availability of barren space for power generation from the renewable sources such as solar, wind, bio-energy and small hydro. The available unused potential of various energy sources in different states of India have been identified. The current status in market, policies, and various constraints of renewable technologies in India has also been summarized. © 2018, International Journal of Renewable Energy Research.