Maharashtra wants a battery on every job above 100 kW

Maharashtra notified its Renewable Energy and Energy Storage Policy in March 2026, and buried inside a ten year state policy document is a line that changes what you can sell to a factory in Pune from this financial year.

New rooftop solar above 100 kW has to come with a battery.

What the policy actually requires

For rooftop projects above 100 kW, and for open access and captive projects above the same threshold, the requirement is storage equal to 50 percent of the renewable capacity, for a minimum of two hours, effective from April 2026. For projects commissioned after FY 2030-31, the duration requirement rises to four hours while the ratio stays at half.

Maharashtra is the first state to write storage into rooftop solar this way. Its targets explain why: 65 percent of electricity demand from renewables by FY 2035-36, and storage on the order of 100 GWh a day. A state that intends to run on that much renewable energy cannot keep absorbing unmanaged midday export from thousands of commercial rooftops.

The policy pairs the mandate with incentives. Storage systems drawing power for charging are exempt from transmission charges, distribution demand charges, electricity duty and cross subsidy surcharge, and captive green open access projects with storage get a ten year electricity duty exemption.

What that means in kilowatt hours

The arithmetic is not complicated, and it is worth doing in front of the customer rather than describing.

A 200 kW rooftop system needs 100 kW of storage power for two hours, which is 200 kWh of usable capacity. A 120 kW system needs 60 kW and 120 kWh. Note that both numbers matter: the power rating sets the inverter and the connection, the energy rating sets the cells, and a quotation that gives only one of them is incomplete.

Two details to settle with the supplier before you put any of this in a proposal:

• Usable versus nameplate capacity. Depth of discharge and degradation mean a nameplate 200 kWh pack is not 200 kWh of compliance on year ten. Ask what the number refers to.
• Round trip efficiency. Energy in is not energy out. The gap comes out of the savings you are about to promise.

What it does to the number the customer cares about

Be straightforward here, because the customer will work it out anyway. The battery adds cost and does not add generation. Payback on the same roof gets longer.

What the battery adds instead is control over when the energy is used, and in Maharashtra that is worth real money because commercial tariffs are time differentiated. Energy generated at noon and pushed into the evening peak is worth more than energy exported at noon, particularly now that the state has attached a grid support charge to exported and generated units for larger consumers. That charge, and the wider narrowing of net metering, is covered in net metering is being rewritten.

So the honest framing to a factory owner is this. The battery is not optional above 100 kW, it lengthens the simple payback, and it partially earns its place back through peak shaving, demand management and protection from the next tariff revision. Model all three rather than asserting them.

The customer sitting at 95 kW

This conversation is coming, so decide your position before it does.

A customer who would have installed 120 kW will ask whether they should install 99 kW instead and avoid the battery entirely. Sometimes that is a legitimate design answer, especially where the roof or the sanctioned load was marginal anyway. Sometimes it is an attempt to split one plant into two connections, which is the kind of thing that survives until an inspection and then does not.

The useful response is to model both. Show the 99 kW system without storage and the 150 kW system with it, side by side, with the tariff the customer actually pays. Often the larger system with storage wins on self consumption alone once the evening load is included, and the customer reaches that conclusion themselves instead of being argued into it.

What to change in your own process

Three things, none of them large:

1. Add storage to your standard bill of materials template for anything above 100 kW in Maharashtra, so it is never a late surprise in a negotiation.
2. Ask for the load profile earlier. Sizing a battery without knowing when the customer's demand peaks is guesswork, and the mandate has made that guess expensive.
3. Quote power and energy separately, with usable capacity, warranty cycles and round trip efficiency stated. A customer comparing two battery quotations has no way to tell them apart otherwise, and the cheaper one usually wins by omitting something.

The short version

• Maharashtra's RE and Storage Policy, notified in March 2026, requires storage on new rooftop solar above 100 kW from April 2026.
• The requirement is 50 percent of renewable capacity for two hours, rising to four hours for projects commissioned from FY 2030-31.
• A 200 kW system therefore needs 100 kW and 200 kWh. Quote power and energy separately.
• Storage charging is exempt from transmission charges, distribution demand charges, electricity duty and cross subsidy surcharge.
• The battery lengthens simple payback and earns some of it back through peak shaving. Model it, do not assert it.
• Expect the customer who wants to stop at 99 kW. Model both options rather than arguing.

Sources

• Maharashtra Renewable Energy and Energy Storage Policy 2025-26 to 2035-36, EQ Magazine
• Maharashtra BESS Mandate 2026: Solar Above 100 kW, Reslink Energy, trade coverage
• Maharashtra Solar Storage Mandate 2026: C&I Rules Above 100 kW, Sun Wave, trade coverage