Maharashtra's Storage Mandate Makes C&I Solar Loans 50% Bigger

Maharashtra just made every C&I solar loan above 100 kW 50% bigger. Under the state Government Resolution of 18 March 2026, new projects seeking connectivity from 1 April 2026 must add storage equal to 50% of their capacity for at least two hours. The loan got 50% bigger. The question for NBFC credit teams is whether the credit did.

The working below uses an illustrative 1 MW rooftop solar file to show what the mandate does to ticket size, debt service and DSCR, and why the borrower's load, not the battery, decides the outcome.

What the mandate adds to a 1 MW file

• Before: 1 MW rooftop solar at ₹3.6 Cr
• From 1 April 2026: the same solar plus a 500 kW / 1 MWh battery, ₹5.4 Cr (+50%). The battery adds ₹1.8 Cr (1,000 kWh × ₹18,000 per kWh)
• Debt at 70%: ₹3.78 Cr, up from ₹2.52 Cr
• Debt service a year: ₹78.9 L, up from ₹52.6 L (₹3.78 Cr ÷ 4.789, at 10.5% over 7 years)
• The battery's own hurdle: ₹26.3 L a year, its ₹1.26 Cr of debt ÷ 4.789

Solar on its own produces ₹93.6 L of cash a year (14.5 lakh kWh × ₹6.8 solar-hour rate, less ₹5 L O&M), for a solar-only DSCR of 1.78x. The battery needs ₹29.3 L a year to break even: ₹26.3 L of debt service plus ₹3 L of O&M. In the weakest battery case, project DSCR in year 1 falls to 1.25x, a loss of 0.53x of headroom.

Same battery, ₹7.9 L or ₹37 L a year

What the 1 MWh battery earns depends entirely on the borrower's load. Project DSCR = (₹93.6 L + battery income − ₹3 L) ÷ ₹78.9 L total debt service.

• Case A, ToD arbitrage only: ₹7.9 L a year (297 MWh × ₹10.2 − 330 MWh × ₹6.8). Project DSCR 1.25x. The battery covers its own debt 0.2x; solar subsidises it.
• Case B, shift unbanked solar past 17:00: ₹20.4 L a year (297 MWh × ₹10.2 − 330 MWh × ₹3). Project DSCR 1.41x. Covers its own debt 0.7x; solar still subsidises it.
• Case C, B plus a 250 kVA demand cut: ₹37.0 L a year (₹20.4 L + 250 kVA × ₹555 × 12). Project DSCR 1.62x. Covers its own debt 1.3x and pays its own way.

In two of three cases, solar carries the battery. And if the load needs only 500 kWh, ₹90 L of the ₹1.8 Cr earns nothing.

Year seven: the battery shrinks, the EMI doesn't

At an illustrative 2.5% annual fade, 1 MWh becomes 825 kWh (82.5% usable) by year seven, still inside a 7-year tenor. Battery income falls 12.5% below the proposal by year 5 and 17.5% by year 7. Staying 2-hour compliant needs a ₹18–24 L top-up (150–200 kWh × ₹12,000). Most proposals simply repeat Year-1 battery income for the whole tenor.

Each risk maps to a party and a contract:

• OEM: ~70% capacity at ~6,000 cycles or 10 years (typical LFP warranty). Backed by the warranty.
• EPC: −5.6% energy if round-trip efficiency falls from 90% to 85%, or −7.2% if availability falls from 97% to 90%. Backed by a performance guarantee.
• Borrower: 4,620 cycles in 7 years at 2 a day (2 × 330 × 7). Backed by your pricing.

Ask for the Year-7 number, map each risk to a contract, and price whatever stays with the borrower.

The new credit memo: six questions before you sanction

Underwrite the hours, not the headline.

1. Sizing basis: mandate floor or load-optimal? The gap, in ₹.
2. Battery coverage: is net battery income ÷ its own debt ≥ 1.0x?
3. DSCR both ways: solar-only and solar + battery, minimum over the tenor.
4. Year-7 income: fade modelled, top-up funded.
5. Warranty vs dispatch: planned cycles a year vs the OEM cap.
6. Guarantee cover: RTE and availability shortfall, who pays?

Sources and assumptions. Verified from public sources: storage rule, Maharashtra GR of 18 March 2026; ToD, solar hours −15 to 25% (20% used) and 17:00–24:00 +20%, with banking 09:00–17:00 (MERC); demand charge ₹555/kVA-month, HT-I (MSEDCL MYT, FY26). Illustrative assumptions: ₹8.5/kWh base tariff, ₹36/Wp solar, ₹18,000/kWh battery, 1,450 kWh/kWp, 70:30 debt at 10.5% over 7 years, 90% usable, 90% RTE, 330 cycles, O&M ₹5 L + ₹3 L, unbanked solar at ₹3/kWh, 2.5%/yr fade. Ingro Sims runs 8,760-hour sizing and a lender-grade cashflow on the borrower's own load. It is an assessment aid; the credit authority still takes the decision.