CAPEX vs RESCO Calculator
Own vs zero-investment PPA — IRR, NPV & 25-year cashflow
Free · No sign-up · Computed instantly on your device
Project & Commercial Inputs
Defaults reflect a typical Indian society or commercial rooftop. Adjust to your quotation and PPA offer.
Models 25 years with 0.5%/yr module degradation and 5%/yr O&M inflation. RESCO assumes zero investment and zero O&M liability. Indicative only — validate against your actual quotation, PPA terms, and tax position before a board decision.
25-year advantage of owning (CAPEX) over RESCO
₹1,64,52,641
CAPEX delivers more lifetime value at these assumptions — provided the capital is available.
CAPEX (Own It)
- Investment
- ₹45,00,000
- Year-1 benefit
- ₹12,70,000
- NPV @ 8%
- ₹1,20,28,208
- IRR
- 30.5%
- Payback
- 3.4 yrs
- 25-yr net
- ₹3,77,05,330
RESCO / OPEX (PPA)
- Investment
- ₹0
- Year-1 saving
- ₹5,25,000
- NPV @ 8%
- ₹78,81,788
- IRR
- n/a (no outlay)
- Payback
- Immediate
- 25-yr net
- ₹2,12,52,689
Cumulative Cashflow — CAPEX vs RESCO
Where the green line crosses zero is CAPEX payback; where it crosses blue, ownership overtakes the PPA.
Investment
₹45,00,000
Project IRR
30.5%
Payback
3.4 yrs
About This Calculator
This is the decision every housing-society committee and facility manager faces: buy the solar plant outright and keep all the savings, or take a RESCO/OPEX deal with zero investment and buy the power at a discounted tariff. The calculator models both over 25 years, returning the numbers a treasurer needs to present — IRR, NPV, simple payback, and the cumulative cashflow curve where ownership overtakes the PPA.
The model applies 0.5%/year module degradation, escalating grid and PPA tariffs, O&M inflation, and (optionally) the 40% written-down-value accelerated depreciation available to tax-paying businesses. Housing societies without business income should leave accelerated depreciation off — it materially changes the answer.
Frequently Asked Questions
- Is CAPEX or RESCO Better for a Housing Society?
- CAPEX usually delivers higher lifetime savings and asset ownership, with typical payback of 3–5 years. RESCO wins when capital is genuinely unavailable. Societies with reserves — or access to a solar loan — generally do better owning.
- What IRR Is Considered Good for a Solar Project?
- Indian commercial rooftop projects commonly show 18–28% IRR without tax benefits, rising above 30% for businesses claiming accelerated depreciation. Compare the result against your organisation’s cost of capital rather than an absolute benchmark.
- Should Societies Claim Accelerated Depreciation?
- Generally no — accelerated depreciation is a tax shield requiring business income. Cooperative housing societies typically cannot use it, so leave the toggle off for a realistic society comparison.