Two routes to cheaper solar power — same grid, very different rules. Here is how to pick the right one for your business.
Indian MSMEs consumed roughly 22% of the country's total electricity in FY2024. Yet fewer than 3% have moved to any form of renewable procurement. The cost gap between grid tariffs and a well-structured solar arrangement is now ₹1.50–₹3.00 per unit in most industrial states — a saving that flows directly to operating margins. Two structures dominate the conversation: Open Access (OA) and Group Captive (GC). Understanding which one fits your load profile, ownership appetite, and state regulations can save you years of the wrong contract.
Open Access lets an eligible consumer purchase power from a third-party generator and wheel it across the DISCOM network to their facility. The consumer pays wheeling charges, Cross-Subsidy Surcharge (CSS), and grid support charges — but the per-unit landed cost still undercuts the DISCOM tariff in most states. Eligibility typically starts at 100 kW (HT connection) and goes up from there. The key advantage is simplicity: you sign a Power Purchase Agreement, the generator delivers, and you pay one monthly invoice.
The key risk is CSS variability. Maharashtra and some DISCOMs in Tamil Nadu have notified CSS levels that erode or eliminate the saving for certain consumer categories. Always model the current CSS before signing a long-term OA contract.
Group Captive is a specific legal structure under the Electricity Act 2003. A Special Purpose Vehicle (SPV) owns the solar plant. You — along with other consumers — hold at least 26% equity in the SPV and consume at least 51% of the plant's generation in proportion to your equity stake. If you meet those two thresholds, CSS is fully exempt under the GC route.
This is the single biggest financial lever in renewable procurement for MSMEs in high-CSS states. In Maharashtra, for example, the CSS exemption under Group Captive can save ₹1.80–₹2.20/unit over an OA arrangement of equivalent scale in the same location.
| Factor | Open Access | Group Captive |
|---|---|---|
| Minimum load (typical) | 100 kW (HT) | Variable — depends on equity share |
| CSS applicability | Yes — state-specific | Exempt (if thresholds met) |
| Equity commitment | None | Min. 26% in SPV |
| Contract complexity | Low — standard PPA | High — SHA + PPA + equity docs |
| Tariff lock-in period | 1–15 years | 15–25 years typically |
| Best for | HT consumers in low-CSS states; quick deployment | High-load MSMEs in Maharashtra, TN, UP |
| Balance-sheet impact | Off-balance sheet (pure PPA) | Equity appears on balance sheet |
Step 1 — Check your CSS level. Pull the state SERC order for your consumer category and calculate what CSS you would pay under OA. If CSS wipes out more than half your saving, Group Captive is almost certainly the better path.
Step 2 — Assess your load hours. Group Captive economics work best for two-shift and three-shift operations (4,000–7,000 annual load hours). Single-shift MSMEs with low load factors may not consume enough to hit the 51% requirement comfortably.
Step 3 — Model equity appetite. Group Captive requires real equity — typically ₹25–₹60 lakhs for a 500 kW share in a 2 MW plant. This is long-term locked capital. If cash is constrained, OA gives you the same solar tariff with zero equity commitment.
Step 4 — Review aggregator credibility. Both structures are only as good as the developer or aggregator behind them. Verify track record, operational projects, and ALMM-compliant module sourcing before signing.
For most MSMEs in Maharashtra, Tamil Nadu, or Uttar Pradesh where CSS is material, Group Captive is the stronger long-term play — but it requires equity commitment and a reliable aggregation partner. In Gujarat, Rajasthan, or Karnataka — where CSS is moderate and OA terms are more transparent — Open Access is easier to execute and still delivers 20–30% savings. The optimal decision depends on your specific load profile, state, and counterparty.
Wattency's assessment team can run both scenarios against your last 12 months of electricity bills in a free consultation. The numbers rarely lie.