Biofuels are renewable energy sources derived from biological materials, and they are categorized into four generations based on feedstock types, production technologies, and environmental impact. Each generation of biofuels reflects the evolution of biotechnology in improving sustainability, efficiency, and energy yield. The first-generation biofuels were the earliest forms of bioenergy derived from food crops and edible biomass. These include bioethanol from sugarcane, corn, and wheat, and biodiesel from vegetable oils such as soybean, palm, and rapeseed. The salient feature of first-generation biofuels is that they utilize readily available carbohydrates, lipids, or starches in crops that are also part of human diets. Production methods are relatively simple, involving fermentation for ethanol and transesterification for biodiesel. However, the major drawback is competition with food supply, leading to concerns over food security, land use, and price volatility. Additionally, the energy balance of some first-generation biofuels is not highly favorable, meaning the energy input for cultivation, harvesting, and processing can sometimes offset the energy output. Despite these limitations, first-generation biofuels played a critical role in demonstrating the feasibility of bioenergy as an alternative to fossil fuels. Second-generation biofuels emerged to address the limitations of first-generation biofuels by using non-food lignocellulosic biomass, agricultural residues, and waste materials as feedstocks. These include crop residues such as straw and husks, forestry residues, and dedicated energy crops like switchgrass and miscanthus. The key feature of second-generation biofuels is that they do not compete