crop residue (agricultural residue)

Crop residue is the plant biomass left in fields after harvest of the economic part — straw, stalks, husks, leaves, stubble, and roots — generated at scale across Indian agriculture. India produces an estimated 500–550 million tonnes of crop residue annually, dominated by paddy straw (140 million tonnes), wheat straw (130 million tonnes), sugarcane trash and bagasse (100 million tonnes), cotton stalks (50 million tonnes), and maize stover (35 million tonnes). Of this total, 30–40% (140–180 million tonnes) is burnt in fields or has no productive use, generating both an environmental crisis and a feedstock opportunity for biogas and biomass-energy projects.

For Indian CBG plants, paddy straw is the marquee feedstock — Punjab and Haryana alone generate 35–40 million tonnes annually, with the post-Kharif 2–3 week burning window driving Delhi air quality crises every October–November. Paddy straw has high lignocellulose content (C:N 80–90, lignin 12–18%) and a methane potential of 200–300 Nm³ per tonne VS after mechanical and biological pretreatment. SATAT-scheme paddy straw CBG plants typically pay ₹2,000–3,500 per tonne delivered at the gate, opening a meaningful new farmer revenue stream that competes with the cost of burning (which the Supreme Court and NGT have repeatedly tried to ban with limited success).

Operational challenges with crop residue are real. Seasonal availability (4–6 week harvest windows per crop) requires 8–12 months of storage capacity, which adds ₹2–4 crore of capex for baling, transport, and covered storage at 100 TPD scale. High silica content in paddy straw (10–20% of ash) accelerates wear on shredders and pumps, requiring 20–30% higher maintenance budget. Pretreatment by mechanical chopping plus mild alkaline or steam-explosion processing adds ₹500–1,500 per tonne but doubles methane yield. Successful Indian paddy straw CBG plants — IndianOil's Panipat (15 TPD CBG, 500 TPD paddy straw input), HPCL's Badaun — have invested heavily in feedstock logistics, with dedicated baler fleets and farmer cooperative tie-ups across 30–50 km catchments.

• Plant biomass left after harvest: 500–550 million tonnes/year in India, 30–40% burnt or unused.
• Paddy straw alone: 140 million tonnes/year; 35–40 million tonnes in Punjab+Haryana.
• CBG methane potential 200–300 Nm³/tonne VS after pretreatment; gate price ₹2,000–3,500/tonne.
• Logistics, storage, and pretreatment add ₹2,000–5,000/tonne to landed feedstock cost.