Rooftop Solar (RTS) in India
The PM Surya Ghar Muft Bijli Yojana has significantly boosted Rooftop Solar (RTS) installations in India, adding 5.21 GW last year, predominantly in the residential sector. Despite this growth, several challenges and considerations have emerged.
Challenges of Grid Stability and Storage
- Increased solar penetration raises concerns about grid stability, reliability, and intermittency.
- The Ministry of Power suggested a two-hour storage mandate with RTS to offset these issues, although it remains advisory for now.
- Cost is a significant barrier to storage adoption, as batteries remain expensive despite decreasing prices.
- Current net-metering frameworks allow the grid to act as a virtual battery, drawing mid-day exported power at night with minimal additional cost.
Financial Considerations
- The PM Yojana provides greater subsidies for smaller RTS systems, benefiting poorer households.
- Diseconomies of scale for small users are evident when adding storage, with a 1 kWp system doubling in cost with storage.
- The payback period for RTS with storage can double, making it financially unviable in some states.
Technical Barriers
- Hybrid RTS systems require hybrid inverters and battery storage, with technical inefficiencies present in current systems.
- Lack of standardization in battery operating voltages creates market inconsistencies, necessitating guidelines and optimized design to enhance efficiency.
Market Viability and Incentives
- Time-aware tariffs and compensation for additional services by storage are crucial to maximizing battery storage potential.
- India's retail electricity pricing distorts solar adoption incentives, particularly affecting high electricity consumers.
- Aligning true system costs with consumer tariffs is essential, as demonstrated by California's Net Energy Metering 3.0 model.
Strategic Recommendations
- Appropriate compensation mechanisms are needed to encourage hybrid RTS adoption without deterring potential customers.
- Establishing clear policies for technical integration and financial feasibility is crucial for sustainable RTS and storage growth.