Transport distance (feedstock transport radius)

Transport distance — the road distance between feedstock source and biogas plant gate — is one of the most decisive factors in CBG plant siting and economics, because biomass transport cost scales almost linearly with distance while delivered feedstock value remains essentially constant. The economics of biomass transport are dominated by truck capacity (typically 9–12 tonnes per trip in Indian conditions), diesel cost (Rs 90–95 per litre at 4–5 km per litre), driver and helper wages, loading and unloading labour, return haulage, and Regional Transport Office permits. As a rule of thumb, transport of moist biomass costs Rs 4–8 per tonne-kilometre, meaning a 50 km haul adds Rs 200–400 per tonne to delivered cost.

The economically viable collection radius depends on the value density of the feedstock. High-value, low-moisture feedstocks like sugarcane bagasse (Rs 1,800–2,500 per tonne, 50% moisture) can support 50–80 km hauls. Loose paddy straw and wheat straw (Rs 1,500–2,500 per tonne, 15% moisture but very low bulk density of 80–120 kg/m3) face a different constraint — truck volume not weight is limiting, raising effective transport cost to Rs 8–12 per tonne-km without baling. Fresh, high-moisture energy crops (Napier grass at 75% moisture, Rs 800–1,500 per tonne) are essentially undeliverable beyond 25–40 km because transport cost exceeds gross feedstock value. Press mud and dairy manure sit between, with viable radii of 30–60 km depending on local availability.

Indian CBG developers manage transport distance through three strategies. Site within a feedstock-dense region — most operational plants sit within sugar mill clusters, dairy zones, paddy belts, or urban-organic-waste collection areas. Densification at source — installing balers (12–15 kg/m3 to 150–200 kg/m3) and shredders at feedstock collection points triples or quadruples the economic radius for residues. Hub-and-spoke logistics — primary aggregation at village or block-level centres followed by bulk transport to plant. The standard SATAT feasibility study includes a sensitivity analysis on transport distance, with project IRR typically falling 0.5–1.0 percentage points for every 10 km increase in weighted-average collection distance. This is why feedstock supply contracts often include distance-banded pricing and why developers prefer captive plantations within 5–15 km of the plant for the base load.