Maharashtra requires batteries on solar above 100 kW, including systems behind the consumer's own meter
A storage mandate attached to the right to generate is a participation rule, not an engineering one. Above 100 kW in Maharashtra, self supply now carries a capital condition set by the state rather than by the site, and the threshold falls squarely on commercial and industrial rooftop, which is where India’s distributed solar economics actually work. The policy is unusually candid about the direction: it describes net metering for prosumers as highly concessional and says it is important to limit those services to smaller consumers who have limited options. The critique that matters is not that the diagnosis is wrong, because cross subsidy inside a loss-making DISCOM is real, but that the instrument mandates an asset instead of pricing a service: 1 MWh per MW is payable on day one whether or not the site ever leans on the grid, and a consumer willing to pay a cost-reflective banking charge is offered no such option. India’s most industrialised state is drawing a line under which size of consumer is still allowed cheap self supply, and other states read Maharashtra.
Maharashtra requires batteries on solar above 100 kW, including systems behind the consumer's own meter
A state FAQ settles the question trade commentary had been guessing at: one megawatt-hour of storage per megawatt of connectivity, and no exemption for projects that never asked the DISCOM for anything.
The Energy Department of the Government of Maharashtra has published a frequently asked questions document (Version 1.0, August 2026) on the Maharashtra Renewable Energy and Energy Storage Policy 2025-26 to 2035-36, which was notified by Government Resolution dated 18 March 2026 under unique code 202603181848365810. Its Section B is headed "Mandatory Energy Storage Requirements", and it answers the question the market was actually asking.
Asked whether a new renewable project selling to open access consumers, and requiring neither banking nor balancing support, can be exempted from the storage mandate, the document does not grant the exemption. It states instead that all new renewable projects over 100 kW must carry storage equivalent to 50 per cent of the renewable capacity for a duration of two hours, citing section 7.2 at page 22 of the policy. A later answer states the arithmetic that follows: 1 MWh of battery per MW of connectivity.
Three implementation details matter more than the headline figure.
First, the threshold is measured at the connection, not at the enterprise. The mandate applies per connectivity point and is sized on connectivity, so a non-co-located hybrid project needs storage at each injection point rather than one pooled battery.
Second, behind-the-meter systems are inside the perimeter. The FAQ states that projects above 100 kW connected behind the consumer meter, rooftop PV or onsite may also use the sizing flexibility, at a minimum battery power rating of 25 per cent of project capacity and a storage duration of four hours. That is the same 1 MWh per MW expressed differently, and it confirms that a large commercial rooftop serving its own load is covered, not only power sold to third parties.
Third, storage is a condition of commissioning rather than a promise. Projects requiring a battery must reach commercial operation with it; where capacity is commissioned in phases, proportional battery capacity must be commissioned alongside. MEDA is to enforce sizing and commissioning through its single window portal.
Projects that received in-principle grid connectivity before 18 March 2026 remain under the 2015 or 2020 renewable policies and, the FAQ is explicit, have no option to migrate to the new one. A separate and more demanding figure applies to the incentive route: long-term captive green open access projects seeking the ten-year electricity duty exemption under section 7.2.2 must carry 2 MWh per MW of contracted renewable capacity, that is four hours at 50 per cent.
Mercom India reported the clarification on 17 September 2026, confirming that open access projects above 100 kW require storage even without banking. Its article is paywalled beyond the opening paragraph.
Why it matters
A storage mandate attached to the right to generate is a participation rule wearing engineering clothes. Above 100 kW in Maharashtra, the cost of supplying yourself now includes a capital item chosen by the state rather than by the site, and the threshold lands precisely on commercial and industrial rooftop, which is where India's distributed solar economics work best.
The unusual thing about this policy is that it says why. The policy text argues that concessional provision of banking and balancing distorts price signals, and that the resulting losses fall on smaller consumers who cannot exercise choice. It then extends the argument to rooftop directly: "net metering services provided to prosumers with onsite renewable system is also highly concessional", and it concludes that such services should be limited to smaller consumers with no access to electricity markets.
That is a coherent position, and it is worth taking seriously rather than dismissing. Cross-subsidy inside a loss-making distribution utility is real, and a large factory exporting at retail credit is genuinely being carried by someone. But the instrument chosen does not price the service; it mandates an asset. A battery sized at 1 MWh per MW is a blunt proxy for the balancing burden a given site actually imposes, and it is payable in full on day one whether or not the site ever leans on the grid. A consumer who would happily pay a cost-reflective banking charge is offered no such option. The policy diagnoses a pricing failure and prescribes hardware.
The direction is the part to watch. Maharashtra is not removing the right to self-supply; it is drawing a line under which size of consumer still gets it cheaply, and putting that line at 100 kW. India's most industrialised state has decided that distributed generation is a concession to be rationed by scale, and other states read Maharashtra.
India context
Maharashtra had roughly 5 GW of installed rooftop solar as of January 2026 including PM Surya Ghar, by the policy's own count, spread across residential, commercial and industrial segments. Net metering in the state runs under the MERC (Grid Interactive Rooftop Renewable Energy Generating Systems) Regulations, 2019, amended in 2023 and 2024, which superseded the 2015 net metering regulations; under net metering or net billing, sanctioned renewable capacity may not exceed contract demand. MERC has separately specified a renewable purchase obligation of 43.33 per cent by FY 2029-30 and a 4 per cent energy storage obligation for obligated entities, which is the supply-side counterpart to what is being asked of consumers here. The policy also sets a target of 5 GW, or 10 billion units, of long-term green open access procurement.
What is still unknown
The blanket figure of 50 per cent for two hours is stated in the government FAQ with a reference to section 7.2 at page 22, but section 7.2 is titled as covering direct procurement by medium and large consumers through long-term green open access. The underlying policy sentence could not be read: the relevant pages of the policy PDF use a custom font encoding that local text extraction returned as unreadable. Whether the mandate is drafted as a general rule or as a Green OA clause that the FAQ has generalised is therefore a question for the notified text, not for this piece. [UNVERIFIED: the wording of the storage mandate at section 7.2, page 22 of the policy]
It is also unresolved whether a distinct September 2026 clarification document exists or whether Mercom is reporting the August FAQ; no document number or issuing date for a September instrument was located. Residential rooftop below 100 kW appears untouched, and nothing in the FAQ suggests otherwise, but no provision was found stating so positively. The cost of compliance is the missing number that decides whether this is a speed bump or a stop: [NEEDS DATA: delivered cost of 1 MWh of battery storage in Maharashtra in 2026, per MW of solar connectivity] and [NEEDS DATA: count of Maharashtra commercial and industrial rooftop systems above 100 kW installed or in the pipeline].
Sources
- Government of Maharashtra, Energy Department, FAQ document Version 1.0, August 2026: https://www.mahadiscom.in/wp-content/uploads/2026/08/FAQs-New-RE-Policy-BESS-2025-26-To-2035-36-1.pdf
- Maharashtra Renewable Energy and Energy Storage Policy 2025-26 to 2035-36, Government Resolution dated 18 March 2026, unique code 202603181848365810: https://cdnbbsr.s3waas.gov.in/s3c0af6df3a5a0ba53004ab39704a9a7f6/uploads/2026/05/202605131257891591.pdf
- Mercom India, 17 September 2026 (paywalled beyond the opening): https://www.mercomindia.com/maharashtra-clarifies-mandatory-energy-storage-rules-for-renewable-projects
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