What determines CBG plant cost?
CBG project cost is not controlled by output capacity alone. Feedstock reception, storage, preprocessing, digester type, civil works, gas upgrading, compression, cascade or pipeline facilities, digestate processing, utilities, roads, fire systems, laboratory, tax, contingency, working capital, and finance costs can materially change the budget.
- Define whether TPD means feedstock input or saleable CBG output
- Separate EPC cost from total installed and total project cost
- State land, tax, IDC, contingency, storage, and offsite exclusions
- Use dated vendor quotations and site-specific civil assumptions
Base-case unit economics at ₹105/kg CBG
The model CBG selling price has been revised upward from ₹75/kg to ₹105/kg — a 40% increase in modelled realisation. Against this price, the base case considers ₹65/kg of total cost: ₹30/kg bank or finance cost, ₹20/kg running expenses (electricity, water, labour, logistics and other routine operating expenses), and ₹15/kg contingency. That leaves ₹40/kg of CBG profit: ₹105 − ₹30 − ₹20 − ₹15 = ₹40 profit per kg of CBG.
- CBG selling price: ₹105/kg, revised from the earlier ₹75/kg model
- Bank / finance cost: ₹30/kg
- Running expenses: ₹20/kg — electricity, water, labour, logistics, and routine operating expenses
- Contingency: ₹15/kg
- Total considered cost: ₹65/kg
- Illustrative CBG profit: ₹40/kg
Annual economics for 3, 6 and 12 TPD plants
All annual calculations use 350 operating days per year at 100% capacity utilisation. A 3 TPD plant produces 3,000 kg of CBG per day — 10,50,000 kg per year — earning ₹11.03 Cr of CBG revenue and incurring ₹6.825 Cr of CBG cost, leaving ₹4.20 Cr of CBG profit. A 6 TPD plant earns ₹22.05 Cr of CBG revenue (₹13.65 Cr cost, ₹8.40 Cr CBG profit) and a 12 TPD plant earns ₹44.10 Cr (₹27.30 Cr cost, ₹16.80 Cr CBG profit). Adding raw FOM and raw LFOM byproduct revenue of ₹1.82 Cr, ₹3.64 Cr and ₹7.28 Cr respectively gives total annual revenue of ₹12.85 Cr, ₹25.69 Cr and ₹51.38 Cr, and illustrative annual profit of ₹6.02 Cr, ₹12.04 Cr and ₹24.08 Cr.
- 3 TPD: ₹12.85 Cr total annual revenue, ₹6.02 Cr illustrative annual profit
- 6 TPD: ₹25.69 Cr total annual revenue, ₹12.04 Cr illustrative annual profit
- 12 TPD: ₹51.38 Cr total annual revenue, ₹24.08 Cr illustrative annual profit
- Approx. feedstock: 100 tonnes/day (3 TPD), 200 tonnes/day (6 TPD), 400 tonnes/day (12 TPD)
- CBG output: 3,000 / 6,000 / 12,000 kg per day at 100% utilisation
raw FOM and raw LFOM byproduct economics
A CBG plant also generates digestate in the form of raw FOM and raw LFOM. When appropriately monetised, these byproducts can contribute an additional revenue stream alongside gas sales. For a 3 TPD plant consuming about 100 tonnes of feedstock per day, output is approximately 20 tonnes/day of raw FOM and 60 tonnes/day of raw LFOM, scaling proportionately at 6 and 12 TPD. At illustrative realisations of ₹2/kg for raw FOM and ₹0.20/kg for raw LFOM, the 3 TPD case generates ₹40,000 and ₹12,000 per day respectively — a total of ₹52,000 per day, or about ₹1.82 Cr per year. The displayed project profit equals CBG profit plus raw FOM and raw LFOM revenue; no separate processing, packaging, transport, or marketing costs are assumed, and these figures describe raw material as generated — not processed, enriched, branded, upgraded, pelletized, or retail fertilizer economics.
- raw FOM: about 20% of feedstock mass, illustrative realisation ₹2/kg
- raw LFOM: about 60% of feedstock mass, illustrative realisation ₹0.20/kg
- 3 TPD example: 20 tonnes/day raw FOM and 60 tonnes/day raw LFOM from about 100 tonnes/day of feedstock
- Byproduct revenue: ₹1.82 Cr/year (3 TPD), ₹3.64 Cr/year (6 TPD), ₹7.28 Cr/year (12 TPD)
How revenue and profit are estimated
Gross revenue begins with saleable CBG quantity multiplied by the net realized price. Other income may include contracted waste-management fees, captive fuel savings, or raw FOM and raw LFOM sales. Each source should be modelled only when quantity, quality, buyer, logistics, and net realization are credible.
- CBG output after ramp-up, downtime, and methane recovery
- Net sale price after delivery and contractual deductions
- Feedstock, logistics, power, labour, chemicals, maintenance, and insurance
- Working capital, major replacement, and product-distribution costs
ROI and payback need a clear definition
Simple ROI compares annual operating surplus with the investment basis, while project IRR and equity IRR use multi-year cash flows. Simple payback ignores the time value of money. A credible investment model should show more than one measure and test downside scenarios.
- Annual EBITDA and EBITDA margin
- Simple and discounted payback
- Unlevered project IRR and levered equity IRR
- NPV, DSCR, breakeven price, and maximum affordable feedstock cost
How to use the free ROI calculator
Enter project cost, annual revenue, annual operating expense, and confirmed assistance to test early scenarios. Set assistance to zero for a downside case. The result is useful for comparison, but a bankable model also needs debt drawdowns, interest, depreciation, tax, working capital, construction schedule, and sensitivity analysis.
- Start with conservative output and price
- Run low, base, and high operating-cost scenarios
- Compare the result before and after debt service
- Request a site-specific model before relying on the headline ROI
Important disclaimer on illustrative figures
Figures shown are illustrative project-level estimates based on the stated assumptions, including 350 operating days, 100% capacity utilisation, ₹105/kg CBG selling price and assumed raw FOM/LFOM realisation. Actual project economics may vary depending on feedstock, financing structure, plant performance, operating costs, offtake terms, logistics, local conditions and byproduct realisation. ₹6.02 Cr, ₹12.04 Cr and ₹24.08 Cr are illustrative annual profit estimates, not guaranteed returns.