One of the newest and most promising fields in sustainable energy is nanotechnology, which has the potential to make significant advancements in the areas of energy generation, storage, and conversion. In this chapter we have reviewed how nanotechnology can be used to advance renewable energy solutions in a variety of applications, such as fuel cells, solar energy, wind energy, and energy storage. For the production of nanoparticles, green synthesis provides an excellent substitute for conventional techniques. This method works under ambient circumstances and is not only safe and benign but also economical, facile, and simple. It has proven possible to develop notable nanoparticles, including gold, silver, and iron oxides, by employing a variety of bio-reductants made from plant extracts. These biological agents play the twin roles of capping and reducing agents by stabilizing the nanoparticles and accelerating the reduction process. It is well known that today’s use of fossil fuels is unsustainable and increases greenhouse gas emissions. In order to harness future energy for a sustainable environment, relevant technologies are examined, such as hydrogen fuel, solar cells based on nanotechnology, and relevant patents. It is also noted that strategies for improving the use of current energy and its byproducts, as well as technologies that ensure the least amount of environmental impact, should be developed. The green synthesis of nanoparticles made from plant extracts and biogenic wastes, highlighting their potential applications in various field of energy production and storage has been presented in this chapter. This abstract emphasises how important nanotechnology is to speeding up the shift to clean and renewable energy sources by providing a thorough analysis of current research and development initiatives.