A transition to sustainable energy is crucial for averting dangerous climate change and realizing sustainable development. Achievement of this objective will require not only technological innovation and behavioral change, but also policy innovation. In this presentation, I address three questions pertaining to policy innovation: i) why do some jurisdictions lead in fostering policy invention? ii) why and how do policies diffuse from leaders to learners or laggards? and, iii) when does policy invention or diffusion result in policy success? Each question is addressed through a different case, involving a policy relevant to the achievement of the sustainable development goal on energy in India. The data for analysis are sourced from 46 elite interviews conducted by the author in India in 2018-19; official documents obtained under the Right to Information Act 2005 or available publicly; and information from news articles, policy reports, and secondary literature. The findings from the three essays shed light on state-level characteristics as well as the activities of different types of entrepreneurs that facilitate policy invention, diffusion, and success. I conclude that better alignment of policy ideas with sustainability issues, politics, and technologies is essential for promoting policy innovation for sustainability and accelerating the Indian energy transition.