This chapter discusses the use of nanofillers in the energy field. Nanofillers, including materials such as carbon nanotubes, graphene, and clay nanoparticles, have unique properties that make them useful in a variety of energy-related applications. For example, they can be used as catalysts, electrodes, and thermal conductors in fuel cells, batteries, and solar cells. Additionally, they can be used as reinforcement materials in composites to improve the strength and thermal stability of structural components. The chapter reviews the current state of research on the use of nanofillers in the energy field, highlighting key findings and identifying areas for future research. It also covers the potential benefits and challenges associated with the use of nanofillers in energy-related applications and provides an overview of the current commercial developments and ongoing research in this field.