India Proposes Mandatory Battery Storage for Solar Projects from 2027

India is preparing for a major change in the way large-scale renewable energy projects are designed and operated. The Central Electricity Authority (CEA) has proposed mandatory energy storage systems for new ground-mounted solar and onshore wind projects commissioned from July 2027.

The proposal is part of the draft Central Electricity Authority (Technical Standards for Construction of Electric Plants and Electric Lines) 2nd Amendment Regulations, 2026.

If the proposal is notified in its current form, new renewable energy projects will need to combine power generation with battery-based energy storage. The move is aimed at making renewable electricity more reliable and easier to use when solar and wind generation is not available.

What Is the New Battery Storage Proposal?

Under the proposed rules, new ground-mounted solar and onshore wind projects commissioned after July 1, 2027 would need to install a co-located Energy Storage System (ESS).

The proposed requirement is:

• Minimum 2 hours of energy storage
• Storage capacity equal to at least 10% of the project's installed capacity
• The storage system would be located along with the renewable energy project

For example, a 100 MW solar project would need at least 10 MW of battery storage for two hours, equivalent to 20 MWh of storage under the proposed first phase.

Simple Example

Suppose a solar power plant has a capacity of 100 MW.

Under the proposed requirement:

Solar Project Capacity: 100 MW
Minimum Storage Capacity: 10 MW
Minimum Storage Duration: 2 hours
Energy Storage: 20 MWh

This means the project could store electricity generated during periods of high solar production and supply that stored electricity later when it is required.

Why Is India Bringing Battery Storage Into Solar Projects?

Solar power generation is naturally dependent on sunlight. Solar plants produce most of their electricity during the daytime, while electricity demand can remain high during the evening.

This creates a challenge for the power grid.

Energy storage can help solve this problem by storing surplus electricity and releasing it when generation falls or demand increases.

According to Reuters, India curtailed nearly 14% of its solar power generation between April and June because of surplus clean electricity during the daytime and limitations in transmission infrastructure.

Battery storage can therefore help India:

• Store surplus solar electricity
• Reduce renewable energy curtailment
• Supply electricity during peak-demand periods
• Improve grid stability
• Make renewable power more dispatchable
• Better integrate large-scale solar and wind capacity

Battery Storage Requirement Will Increase From 2029

The proposed rules are not limited to a two-hour storage requirement.

For projects commissioned after July 1, 2029 and up to June 30, 2031, the minimum storage duration would increase from two hours to four hours, while the storage capacity requirement would remain at 10% of the project's installed capacity.

For example, a 100 MW renewable energy project would require:

This indicates that energy storage is expected to become an increasingly important part of India's renewable energy infrastructure.

Grid-Forming Inverters Also Proposed

Battery storage is not the only proposed change.

The draft regulations also propose new requirements related to grid-forming technology.

Renewable energy plants commissioned after July 1, 2027 would need at least 15% of their inverters to have grid-forming control.

In addition, power conversion systems (PCS) used in battery energy storage systems would need to have grid-forming capability.

What Is Grid-Forming Technology?

Grid-forming technology allows power electronic equipment to actively support important grid characteristics such as voltage and frequency.

This becomes increasingly important as the share of solar and wind power increases because renewable generation can fluctuate depending on weather and availability.

The proposed requirements are therefore aimed not only at adding batteries but also at making renewable power plants more capable of supporting the electricity grid.

Is Battery Storage Mandatory From 2027?

Not yet.

This is an important point.

The CEA has currently issued a draft proposal, and the regulation has not yet become a final mandatory rule.

The draft notification was issued on September 3, 2026, and CEA has invited comments from stakeholders and the public. Comments can be submitted until October 4, 2026.

The proposal will be considered after the consultation period. Therefore, the final requirements could potentially change before notification.

What Could This Mean for India's Solar Industry?

If the proposal becomes a final regulation, it could significantly influence the design of future utility-scale solar and wind projects.

1. Solar Projects Will Move Toward Solar + Storage

Future renewable projects may increasingly be designed as integrated solar-plus-storage plants instead of standalone solar plants.

2. Demand for Battery Energy Storage Could Increase

Mandatory storage requirements could create additional demand for Battery Energy Storage Systems (BESS) in India's renewable energy sector.

3. Project Costs May Change

Adding batteries, power conversion systems and related infrastructure can increase the initial project investment.

However, storage can also provide additional value by allowing electricity to be shifted from periods of surplus generation to periods of higher demand.

4. Grid Integration Could Improve

More storage capacity can help manage fluctuations in renewable generation and reduce the amount of renewable electricity that has to be curtailed.

5. Storage Technology Could Become More Important

The proposal could accelerate investment and innovation in battery technologies, energy management systems, inverters and other storage-related technologies.

What Does This Mean for Solar Panel Manufacturers?

The proposed regulation is primarily focused on renewable power projects and energy-storage systems, rather than changing the technical requirements for solar modules themselves.

However, it could indirectly affect the solar module industry. As large-scale projects increasingly combine solar generation with battery storage, developers may focus more on:

• Higher-efficiency solar modules
• Better land utilization
• Bifacial solar modules
• High-wattage modules
• TOPCon technology
• Advanced inverters
• Solar-plus-storage project design

This could further strengthen the shift toward high-efficiency solar modules for utility-scale projects.

India Is Moving Toward Solar Plus Storage

India's renewable energy sector is entering a phase where generating more solar electricity is only one part of the challenge.

The next challenge is when and how that electricity can be delivered to consumers.

Battery storage can help bridge this gap by storing electricity when renewable generation is high and making it available when generation falls or demand rises.

The proposed CEA rules show that India's future renewable energy planning is increasingly moving toward a combination of solar generation, battery storage and advanced grid technology.

Conclusion

India's proposed battery storage requirement could mark an important step in the country's renewable energy transition.

Under the draft proposal, new ground-mounted solar and onshore wind projects commissioned from July 2027 could require storage equivalent to at least 10% of installed capacity for two hours. From July 2029, the proposed minimum storage duration would increase to four hours while retaining the 10% capacity requirement.

However, these requirements are proposed rules and not yet final. The CEA's consultation process will determine how the final regulations take shape.

If implemented, the policy could accelerate India's shift from standalone renewable generation toward a more flexible solar + battery storage energy system.