Maharashtra Solar Banking 2026: The C&I Playbook
- Posted by Infisol Energy
- April 04, 2026
You installed solar on your factory. You generate power during the day. You thought that extra power would adjust against your electricity bills at night or during evening shift. Sounds fair, right?
Well, in Maharashtra, that is no longer how it works.
The Maharashtra Electricity Regulatory Commission, better known as MERC, has issued a new order under what is called the Multi-Year Tariff framework. And buried in that order is one rule that is quietly hitting the savings of every commercial and industrial solar consumer on MSEDCL’s network.
That rule is called same-slot banking. Let us look at what this rule means and how it affects solar energy consumers.
What Is Same-Slot Solar Banking, Exactly?
Think of solar banking like a prepaid wallet. You generate electricity during the day, send the extra into the grid, and that goes into your “wallet” as credits. Later, when you need power, you draw from the grid and your wallet pays for it.
That wallet used to work like a debit card. You could use your credits any time, day or night. If your factory runs two shifts and your power bills are highest in the evening, no problem. Your daytime solar credits would take care of that.
But under the new MERC solar banking rules 2026, the wallet has time locks on it.
Here is how it works now under the revised Time-of-Day banking framework for MSEDCL consumers:
Normal Hours, 12 midnight to 9 in the morning: Credits earned here can be used during normal and solar hours. But not during evening peak hours.
Solar Hours, 9 in the morning to 5 in the evening: This is when your solar panels generate most of their power. Credits earned in this window can only be used within that same 9am to 5pm window. You cannot carry them forward to your evening bills.
Peak Hours, 5 in the evening to 12 midnight: Credits from this slot can be used anytime. But almost no solar plant generates at this time.
So the practical result is this. Your solar system generates for about eight hours a day. Those credits are now locked to those same eight hours. If your factory’s biggest electricity bills come after 5 pm, standalone solar no longer helps with that part of your bill.
Earlier, solar banking in Maharashtra allowed consumers to use their credits for nearly 17 to 20 hours of the day. The Bombay High Court even stepped in during 2025 and gave temporary relief to solar developers who challenged this restriction. The National Solar Energy Federation of India, known as NSEFI, filed petitions arguing that the rule hurts C&I consumers with different shift patterns. But the Modified MYT Order has now confirmed same-slot banking as the settled framework for new projects under MSEDCL.
This is not a small change. Industry experts estimate that C&I consumers who do not adapt their solar strategy could see effective electricity costs rise by 20 to 30 percent over time, compared to the savings they were planning on.
How Time-of-Day Tariffs Make This Worse for Factories
The same-slot banking rule does not come alone. At the same time, MERC has also changed how electricity is priced depending on when you use it. This is called the Time-of-Day or ToD tariff.
Here is the simple version of what MERC’s ToD framework says:
During solar hours, which is 9 am to 5 pm, you actually get a discount on electricity. The rebate is around 15 percent from April to September and closer to 25 percent from October to March. Grid power is cheaper during this window.
During peak hours, from 5 pm to midnight, you pay a premium on top of your regular tariff. That premium is roughly 20 percent over the base rate.
Now step back and think about what this means for your factory.
Your solar plant generates during the cheapest hours of the day. The hours when grid power is already discounted. And your solar credits are now locked to those same hours. You cannot use them in the evening when your grid bills are the highest, where a 20 percent premium is applied.
Under the old banking rules, daytime solar generation could wipe out your peak-hour bill. That arbitrage is gone unless you add battery storage.
There is also another layer to this for high-tension industrial consumers on MSEDCL. It is called kVAh billing. Most industrial units do not have perfect power quality, and kVAh billing penalises poor power factor directly on your electricity bill. Improving power factor through smarter solar inverters and battery systems is no longer optional. It is one of the clearest ways to protect your tariff outgo under the current MERC framework.
CERC BESS Guidelines 2026: What Changed Nationally
While MERC was making changes at the state level, something equally important happened at the national level.
On March 20, 2026, the Central Electricity Regulatory Commission, or CERC, issued new rules called the Terms and Conditions of Tariff Second Amendment Regulations, 2026. These rules formally brought Battery Energy Storage Systems, or BESS, into the same regulated framework as thermal power plants and transmission assets. Before this, batteries lived in a grey zone. Now they have a clear place in the system.
These are called the CERC IESS guidelines, where IESS stands for Integrated Energy Storage Systems. Here is what this means in plain terms for a factory owner or CFO thinking about solar plus storage.
BESS is now a recognised, bankable asset. Banks and lenders can now look at a BESS project the same way they look at a power plant. That makes project financing easier and more structured. The CERC has set a base return on equity for storage systems, which gives developers and consumers a predictable revenue basis when designing projects.
Technical standards are now clear. The CERC IESS framework requires that BESS systems meet a round trip efficiency of at least 85 percent. In simple terms, for every 100 units of power you put into the battery, at least 85 units should come out usable. Modern lithium iron phosphate batteries, which are the most common type being deployed in India right now, comfortably meet this standard.
Storage gets stronger green credentials. Under a separate CERC amendment to the Renewable Energy Certificate regulations, also issued in March 2026, BESS gets a certificate multiplier of 3.0. Standard solar gets a multiplier of 1.0. This is important for companies with ESG commitments or renewable purchase obligations. A solar plus BESS system gives you three times the green credit value compared to standalone solar.
Central government is funding storage rollout. The Ministry of Power approved a major Viability Gap Funding scheme to support 30 gigawatt-hours of BESS across India. Viability Gap Funding is a government grant that covers part of the project cost when a project is commercially viable but not yet financially attractive enough on its own. This funding is reducing the effective cost of storage at the supply chain level.
And in Maharashtra specifically, the state has gone further. Any new renewable energy project above 100 kilowatts commissioned from April 1, 2026 must include storage. The minimum is storage capacity equal to 50 percent of the renewable capacity, with at least two hours of duration. Storage is now a compliance requirement, not a choice.
Solar Plus BESS ROI for Maharashtra Factories
Here is the part where the story gets interesting.
The same rules that hurt standalone solar actually create a real opportunity for factories that add battery storage to their solar system. The logic is straightforward.
Your solar panels generate power from 9 am to 5 pm. That surplus which you cannot use on-site during the day can be stored in a BESS. Then, when your factory runs its evening shift and grid power is at its most expensive, the battery discharges. You are now running your evening operations on stored solar power instead of expensive grid power with a 20 percent peak premium on top.
This is what is called peak-hour arbitrage. And it is significant.
When you combine the grid charges you avoid, like wheeling charges, cross-subsidy surcharge, and transmission charges, along with the peak-hour premium you escape by using stored solar instead of grid power, the effective saving per unit of stored energy is substantial. Industry analysis in 2026 puts this combined advantage in the range of 30 to 50 percent of your applicable peak grid tariff, depending on your specific MSEDCL category and billing structure.
What does the ROI look like for industrial consumers?
For a well-designed solar plus BESS project in Maharashtra’s C&I sector, financial payback periods in 2026 typically fall in the 4 to 6 year range. Standalone solar under the new banking rules is showing extended payback periods of 7 to 9 years for factories with significant evening and night load, because the key savings from peak-hour offset are no longer available without storage.
There are two tax benefits that improve these numbers significantly for C&I entities.
First, Accelerated Depreciation. Industrial and commercial solar installations in India qualify for 40 percent accelerated depreciation in the first year. This means you can write off 40 percent of your solar asset value against your taxable income in year one, which materially reduces the effective capital cost and brings forward your break-even.
Second, Maharashtra’s Electricity Duty Holiday. For captive renewable energy installations combined with BESS, the state offers a 10-year electricity duty holiday under its 2026 RE policy. Electricity duty is a state levy that typically adds a few percent to your bill. Exemption from it for a decade, on a large industrial load, adds up.
What about factories that already have solar without BESS?
You can retrofit. Adding a battery system to an existing solar plant allows you to recapture the peak-hour advantage that the new banking rules have removed. The cost of retrofitting depends on battery size, chemistry, and site configuration. But given the daily advantage on peak-hour units over multiple years, a well-sized BESS addition can still deliver payback well within the useful life of your panels.
At Infisol, our project teams are seeing this retrofit conversation happening with almost every C&I client who installed solar in Maharashtra before 2025. The economics have shifted. The good news is that the correction is still worthwhile.
3 Questions Every C&I Energy Head Should Ask Now
Whether you are planning a new solar installation or sitting on an existing one, these three questions will tell you how exposed you are to the new rules.
Does your factory’s power consumption peak after 5pm?
If your second shift runs between 5pm and midnight, a standalone solar system under the current MERC banking rules will not reduce that part of your bill. Those are your most expensive units and they are now completely outside the reach of solar credits unless you have storage. If this describes your operation, BESS is not an upgrade. It is a necessity.
Are you billed on kVAh by MSEDCL?
High-tension industrial consumers in Maharashtra are mostly billed on kVAh, not kWh. kVAh billing accounts for your power factor. If your power factor is poor, your effective tariff goes up. Solar inverters with reactive power compensation, especially when paired with BESS, can improve your power factor and reduce your billed kVAh. This is a savings lever that most solar proposals do not even mention, but it is very real under MSEDCL’s current tariff structure.
Is your solar EPC partner working with 2026 numbers?
This one matters more than most people realise. A solar proposal built on banking assumptions from 2024 or early 2025 will show you savings that are no longer achievable under the Modified MYT Order. The financial model needs to account for same-slot settlement, the ToD premium on peak-hour grid draw, the Grid Support Charge that now applies since Maharashtra’s rooftop solar capacity has crossed the threshold that triggers it, and the mandatory storage requirement for new projects. If your proposal does not address all of these, the numbers are not reliable.
How Infisol Designs for the New Rules
Infisol Energy is a solar EPC company working with commercial and industrial clients across Maharashtra. We build, design, and commission solar and solar plus BESS projects for factories, manufacturing plants, and large commercial buildings.
When the MERC Modified MYT Order came out, we went back to every proposal and financial model we had in progress and rebuilt the numbers to match the new framework. That meant accounting for same-slot banking, the revised ToD structure, kVAh billing correction through BESS, and Maharashtra’s mandatory storage requirement for projects above 100 kW.
If you have received a solar proposal recently and want to know whether it reflects the current rules, our team can review it. We will tell you honestly if the savings projections are based on outdated assumptions.
We have also built a Solar Impact Calculator specifically for Maharashtra’s C&I segment. It uses the actual MERC tariff logic, including kVAh billing, seasonal ToD rebates, BESS export credits, O&M cost projections, panel degradation over time, and a 10-year net present value projection. It gives you a real picture of what solar saves for your specific site and load profile under the rules that are actually in effect today.
Frequently Asked Questions
What is same-slot banking in Maharashtra solar?
Same-slot banking is a rule introduced by MERC under the Modified Multi-Year Tariff Order. It means that energy your solar plant generates during the solar hours window, which is 9am to 5pm, can only be used to settle your consumption during those same hours. You can no longer carry those credits forward to offset your evening or night electricity bills. This applies to consumers under MSEDCL.
Does the new MSEDCL solar banking rule apply to Tata Power and Adani consumers?
No. The same-slot banking restriction currently applies only to MSEDCL consumers. If you are a consumer under Tata Power Distribution or Adani Electricity Mumbai, this restriction does not apply to you under the current order. This difference was one of the arguments made by NSEFI in the Bombay High Court challenge.
Is BESS now mandatory for new solar plants in Maharashtra?
Yes, for new renewable energy projects above 100 kilowatts commissioned from April 1, 2026. Maharashtra’s RE Policy requires storage integration at a minimum of 50 percent of your renewable capacity, with at least two hours of storage duration. Projects with a four-hour BESS configuration are eligible for additional benefits including the electricity duty holiday.
What is the CERC IESS tariff amendment 2026 and why does it matter?
The CERC Terms and Conditions of Tariff Second Amendment Regulations, issued on March 20, 2026, formally recognised Integrated Energy Storage Systems as a regulated asset class. For C&I buyers, this matters because it makes BESS bankable, sets clear technical standards like the 85 percent round trip efficiency floor, assigns BESS a 12-year depreciation life, and gives storage projects a certificate multiplier of 3.0 under the Renewable Energy Certificate framework. This is the regulatory foundation that makes solar plus BESS projects easier to finance and more attractive from a green compliance standpoint.