Over the last two decades, sustainable energy technologies have become a critical part and a major contributor to the global supply mix especially in the electricity sector. This is driven by our desire to use sustainable resources to reduce pollution emanating from the current use of fossil fuels, increasing resource security through local generation, and the creation of new industries and jobs. Although these technologies are in some cases still driven by what is termed as support mechanisms or subsidies, the sustainable or renewable energy industry has matured, with huge investments being ploughed into it globally. Global investment in renewable power and fuels (excluding large hydro-electric projects) was around US$286 billion in 2015, nearly 19% higher than the previous year. A large proportion of the funds have targeted solar and wind power, and for the overall investment exceeded that for traditional fossil fuels. Renewable energy is now a major industry sector that is likely to grow further, displacing and augmenting traditional electricity generation facilities as we progress in this century. This lecture will address these technologies and will give a discourse of status, applicability and policy implications, covering solar, wind, and marine energy. It will consider installations at building, village, city and large deployments in farms or arrays.