Cellulosic ethanol is a type of biofuel made from the cellulose found in plant materials, such as grasses, wood, and agricultural residues. Unlike traditional ethanol, which is often produced from food crops like corn and sugarcane, cellulosic ethanol uses non-food biomass, making it a more sustainable option. This process helps reduce greenhouse gas emissions and reliance on fossil fuels. The production of cellulosic ethanol involves breaking down the complex cellulose structure into sugars, which are then fermented to produce ethanol. Advances in technology, including the use of enzymes and microorganisms, are improving the efficiency and cost-effectiveness of this renewable energy source.