The depletion of fossil fuels and the harmful repercussions of their burning have turned focus to the development and implementation of alternative energy sources. Exploring the potential of bioenergy as a replacement for fossil fuels is a significant alternative. Producing bioenergy and biofuels might become a more sustainable choice with the help of nanotechnology. Nanotubes, nanofibers, nanosheets, metal nanoparticles, etc., are only some of the many nanomaterials that have been reported to have a role, either directly or indirectly, in the production process of biofuels. Nanoparticles possess magnetic properties and are only one example of a unique strategy made possible by nanotechnology. Enzymes useful in producing bioethanol or biodiesel may be immobilized on these particles. In addition, the methanogenesis process may benefit from magnetic nanoparticles because of their high coercivity and strong paramagnetic features. Following an overview of bioenergy and biofuel production across the world, this chapter explores the novel ways in which nanotechnology may be applied to these problems and the answers it can provide, before turning to the potential dangers posed by this technology. © 2024 Elsevier Ltd. All rights reserved.