Mechanical renewable fuels is a specialized research area within sustainable energy engineering. It focuses on the development, analysis, and optimization of mechanical systems and processes critical to the production, processing, storage, and application of fuels derived from renewable sources such as biomass, solar, or wind energy. This includes studying technologies like mechanical pretreatment of feedstocks, thermochemical conversion reactors, fuel handling infrastructure, and the performance of renewable fuels in engines and power systems, with the goal of enhancing technical and economic viability for decarbonization.