Rice and Wheat Straw for Biofuel and Bioenergy Production: Implementation Evidence, Environmental Sustainability, and Scale-Up Gaps in Selected Countries

Aim: To evaluate rice- and wheat-residue biofuel pathways through documented implementation cases in India, China, Italy, Denmark, the United States, and Canada, with emphasis on evidence maturity, environmental trade-offs, and scale-up constraints. Approach: A structured comparative narrative review integrated peer-reviewed conversion and life-cycle studies with dated government, laboratory, and facility records. Each numerical observation was classified as measured operation, anticipated process performance, nameplate capacity, historical use, or modelled outcome. Mixed-feedstock attribution and variation in life-cycle assessment boundaries were considered explicitly. Findings: The Panipat plant in India was announced with a design basis of approximately 200,000 tonnes of rice straw and 30 million litres of ethanol per year; the associated 300,000 tonnes of CO₂-equivalent annual avoidance remains a government projection. In Qingpu, China, documented 2020 co-digestion of 2,125 tonnes of dry rice straw and 142 tonnes of fresh manure yielded 442,015 m³ biogas and 662,475 kWh electricity. The historical Tianguan demonstration had a reported capacity, rather than verified annual output, of 3,000 tonnes ethanol per year. Industrial lignocellulosic processing capacity was documented at Crescentino, Italy, whereas Denmark reported an expected ethanol yield exceeding 198 litres per dry tonne of wheat straw in earlier demonstration work. American and Canadian examples show why commissioning, government-fleet use, and later commercial continuity must be evaluated separately. Conclusions: Rice and wheat residues can support renewable fuels and integrated biorefineries, but crop-residue production is not equivalent to a sustainably harvestable supply. Climate and economic outcomes depend on the management baseline, soil-carbon and nutrient requirements, feedstock logistics, process inputs, coproduct treatment, and verifiable operating continuity. The six cases illustrate heterogeneous pathways rather than national or global adoption rates.