THE GREEN ENGINE

Napier Grass: The Powerhouse of CBG

High‑yield, perennial, and regenerative — the ideal feedstock for 24x7 compressed biogas production across Andhra Pradesh & Telangana.

30,000
Acres
contract farming
4
Harvests/yr
year‑round supply
60+
T/ha dry
biomass p.a.
150
m³ biogas/t
per tonne napier
Napier regrowth after harvest
From soil to biomass

Cultivation & Harvesting Practices

Cultivation

  • Propagation: stem cuttings or root slips; planted at 1m x 0.5m spacing
  • Irrigation: drip systems with 60–70% water saving vs. flood
  • Soil prep: light ploughing + organic manure; pH 5.5–7.0 ideal
  • Yield: first harvest at 6–8 months, then every 60–75 days
  • Pest management: integrated, minimal chemical use

Harvesting

  • Cycle: 3–4 harvests annually; ratoon crop regrows quickly
  • Method: mechanical harvesters cut at 10–15 cm stubble height
  • Logistics: chopped (2–3 cm) and transported within 6h to prevent spoilage
  • Biomass: 40–50 tonnes green weight per hectare per cut
  • Moisture: 65–70% at harvest; ideal for ensiling or immediate processing
Biochemical pathway

From Napier to Compressed Bio-Gas

A step‑by‑step transformation: clean energy from green grass.

1. Pre‑treatment
Napier chaffed, soaked, and pasteurised to break lignin.
2. Anaerobic digestion
30‑day retention in sealed digesters at 37–40°C.
3. Biogas raw
55–65% methane, 35–45% CO₂ + traces.
4. Upgradation
PSA / water scrubber → methane >96%.
5. Compression
CBG compressed to 200–250 bar, stored in cascades.
Digester chemistry
  • Hydrolysis: complex polymers → sugars
  • Acidogenesis: volatile fatty acids
  • Acetogenesis: acetate, CO₂, H₂
  • Methanogenesis: CH₄ + CO₂
Key outputs per tonne
🌿 1 tonne Napier → 120–150 m³ biogas
🔥 1 m³ biogas → ~2.1 kWh thermal
⚡ CBG equivalent: ~0.65 kg CNG
🌱 40% bio‑slurry (fertiliser)
Advantage napier

Ideal feedstock characteristics

Perennial, 6‑7 years
Single planting, multiple harvests
Drought tolerant
Survives dry spells, deep root system
High cellulose
38–42% cellulose → methane rich
Low lignin
Easier digestion vs. woody biomass

Napier grass turns marginal land into energy farms – each acre feeds the grid and the farmer.

— Atirath agronomy team
Visual impression
NAPIER GRASS FIELD · 30,000 ACRES
100%
biomass utilization
96%
methane purity
0
fossil CO₂