This contributed volume addresses several environmental problems using nanoparticles/nanomaterials for renewable energy and biofuel production. It presents nanomaterials as catalysts that can enable better selectivity, yield, and quality in renewable energy and biofuel production. The rapid expansion of industries and human population has resulted in a significant increase in the generation of waste and environmental pollution, posing a significant threat to the environment and human health. People are looking for safer and more eco-friendly fuels to meet energy demand and preserve the world for future generations. Renewable energy and biofuels are alternative techniques that reduce fossil fuel consumption. The advancement in the field of nanotechnology has led to the development of nanocomposites/nanomaterials, which are composed of nanoscale particles and polymers. Their application in the environment has shown great potential in addressing environmental issues such as pollution control and waste management. Nanocomposites are advanced materials with unique properties, such as improved mechanical strength, thermal stability, and flame resistance, making them attractive for a wide range of applications, including environmental applications. Nanomaterials show great potential for sustainable biofuel production with commercial feasibility. Nanotechnology-based various conversion routes effectively convert waste biomass into value-added biofuels, such as syngas, biodiesel, and HVO. This book discusses the green synthesis of nanocomposites/nanomaterials for biofuel production and renewable energy. Additionally, it covers techno-economic analysis of bioremediation using green-synthesized nanoparticles/nanomaterials. This book will be helpful for researchers, engineers, and scientists working in the areas of environmental biotechnology, materials science, nanotechnology, environmental science, and engineering.