The Ministry of New and Renewable Energy (MNRE) issued an advisory on 18 February 2025 recommending that Energy Storage Systems (ESS) — commonly referred to as batteries — be co-located with solar power projects. The advisory is primarily directed at large-scale solar developers, but it signals a broader government push toward integrated solar-plus-storage systems that has direct relevance for homeowners in Chennai considering their rooftop solar options under the PM Surya Ghar Muft Bijli Yojana.
What MNRE advised
The advisory makes three core recommendations that reflect the government's evolving understanding of how solar energy can be integrated most effectively into India's power grid:
- Grid stability through storage: Co-locating batteries with solar plants smooths out the natural variability in solar generation — the drops in output caused by cloud cover, early morning ramp-up, and evening ramp-down. Without storage, these fluctuations must be managed by the grid itself, often using expensive conventional power plants as backup. With storage, the solar project itself can manage its own variability.
- Reduced grid integration costs: When solar projects include on-site storage, less investment is required in additional grid infrastructure (transformers, transmission lines, frequency regulation capacity) to safely absorb the solar power being generated. This can reduce costs for the broader electricity system — savings that eventually benefit all consumers, including residential solar users.
- Encouragement across project scales: MNRE's advisory encouraged both large utility-scale solar project developers and rooftop solar installers to evaluate storage integration alongside solar — reflecting the government's recognition that the solar-plus-storage model benefits the grid at every scale, not just at the utility level.
What this means for on-grid rooftop solar in Chennai
The majority of residential PM Surya Ghar installations in Chennai are on-grid systems — solar panels connected to the TANGEDCO grid with a net-metering arrangement. Excess solar power generated during the day is exported to the grid, and homeowners receive electricity credits they can use at night or on cloudy days. This model works well and is fully eligible for the PM Surya Ghar subsidy.
MNRE's advisory does not change the eligibility rules for on-grid systems. However, it does highlight a trend that Chennai homeowners should be aware of:
- On-grid systems are optimal today for most Chennai homes — net metering with TANGEDCO is well-established and the economics are strong, especially with the PM Surya Ghar subsidy.
- Adding a battery (hybrid system) provides power during grid outages — a real consideration in Chennai where grid interruptions can occur — and allows self-consumption of solar power for evening loads without exporting to the grid and waiting for credits.
- MNRE's advisory aligns with a longer-term trend: as rooftop solar adoption grows across Tamil Nadu and the rest of India, utilities like TANGEDCO will manage increasing amounts of variable solar generation. Grid-side storage (from schemes like the BESS VGF programme) and home-side storage (hybrid systems) are both part of the long-term solution.
On-grid vs. hybrid solar — which is right for you?
The table below summarises the key differences to help Chennai homeowners decide which system type fits their situation:
| System Type | Battery | Best For | PM Surya Ghar Eligible? |
|---|---|---|---|
| On-Grid | No | Grid-connected homes wanting to maximise subsidy and net-metering credits | Yes |
| Hybrid | Yes | Homes with frequent power outages or wanting evening self-consumption independence | Yes (on-grid portion of system) |
| Off-Grid | Yes | Remote locations with no reliable grid access | Case by case |
For most Chennai homeowners, an on-grid system with PM Surya Ghar subsidy remains the most cost-effective entry point. A hybrid system makes sense where outage frequency is high or where the homeowner specifically wants evening energy independence. Cluster Energy can advise on the right configuration based on your home's energy profile and TANGEDCO connection details.
Thinking about going solar?
Cluster Energy is MNRE & TEDA approved and offers both on-grid and hybrid rooftop solar systems across Chennai. We handle site surveys, system design, PM Surya Ghar subsidy documentation, and TANGEDCO net-metering coordination end-to-end. Get a free site survey →
