Do not put a residential subsidy into an MSME payback model unless the exact consumer category and official scheme make it eligible. Build the business case from measured daytime load, self-consumption, export treatment, installed cost, finance, degradation, downtime, tax treatment, and replacement risk.
Start with the electricity profile
Use at least twelve months of bills and, where possible, interval data. Separate daytime weekday load, seasonal closures, demand charges, energy charges, taxes, and outages. Solar value depends more on when power is consumed than on an annual bill total.
Verify the consumer category and DISCOM rules
Confirm sanctioned load, connection category, rooftop capacity limit, metering arrangement, approval sequence, export tariff or settlement, and required protection equipment with the relevant DISCOM. Do not copy a residential net-metering or subsidy assumption into a commercial/industrial case.
| Input | Conservative evidence |
|---|---|
| Generation | Site-specific design and loss assumptions |
| Self-consumption value | Avoided applicable energy charge during generation hours |
| Export value | Current written DISCOM treatment |
| Cost | Complete EPC, approvals, structure, metering and finance |
| Long-term risk | Degradation, downtime, cleaning, inverter and roof work |
Run three cases, not one payback number
Use conservative, expected, and upside cases. Vary generation, self-consumption, tariff, downtime, interest rate and replacement timing. Show cash flow after debt service, not merely “annual savings divided by project cost.” Keep working capital separate from the solar project reserve.
Read the loan and EPC contracts together
Match sanctioned equipment, supplier, payment milestones, borrower margin, commissioning evidence, warranties, performance assumptions, insurance and lender security. Do not release the final payment before metering, commissioning data and acceptance are complete.
Understand what the central rooftop programme covers
MNRE’s grid-connected rooftop programme page states that central financial assistance under the described component is for residential electricity consumers, with incentives to DISCOMs. An MSME should verify other central/state programmes, tax treatment or lender products separately instead of assuming residential CFA.
Set stop conditions
- The vendor will not provide a generation model and loss assumptions.
- The DISCOM treatment is verbal or unresolved.
- Payback depends on 100% self-consumption despite low daytime load.
- Roof condition, structural work, fire access, or shutdown cost is excluded.
- Loan repayment starts before realistic commissioning.
Official references
- MNRE — Grid Connected Rooftop Solar Programme — programme scope and residential CFA context.
- MNRE — ALMM — current approved-model/manufacturer material where applicable.
- RBI — Key Facts Statement — APR, charges and repayment schedule for covered term loans.