Researchers have been hard at work developing novel materials with the potential to make energy systems more efficient and environmentally friendly in response to the rising worldwide need for clean, renewable power. The domain of renewable and sustainable energy is seeing nanomaterials as potential candidates due to their exceptional qualities, including a large surface area, adjustable electrical and optical properties, and improved catalytic activity. Solar cells, fuel cells, hydrogen generation, batteries, and supercapacitors are just a few of the renewable energy technologies that nanomaterials might be useful in. Energy conversion and storage devices may be greatly enhanced with the use of nanostructured materials, such as graphene, carbon nanotubes, quantum dots, and metal–organic frameworks. Recent advances in nanomaterial production processes are also covered in the chapter, with an emphasis on sustainable and eco-friendly methods. Also covered are concerns about toxicity and lifespan sustainability, two issues that can arise from using nanomaterials for energy applications. At the end of the chapter, we take a look ahead at how nanomaterials will play a part in solving the world’s energy sustainability problems and at the present research trends that are trying to find solutions.