Third-Party Sale vs Group Captive Solar in India (2026)

Direct answer

Both structures buy off-site open-access solar, and the difference is one word: equity. Third-party sale (TPA) means buying power from a developer's plant - you pay cross-subsidy surcharge plus additional surcharge, landing at roughly ₹6.2-7.5/kWh in North India. Group captive means owning at least 26% equity in the plant and consuming at least 51% of its output among the owner-consumers - which exempts you from CSS, landing near ₹5/kWh. Rule changes effective March 2026 have made the captive test easier to meet as a group but stricter to keep annually.

The statutory captive test (26% and 51%)

Under Rule 3 of the Electricity Rules - retained by the Electricity (Amendment) Rules 2026, notified 13 March 2026 - a plant is "captive" only if it satisfies both conditions (Norton Rose Fulbright analysis, Mar 2026):

1. At least 26% ownership by the captive users, and
2. At least 51% of the aggregate electricity generated is consumed by the captive users, tested every financial year.

A common misconception: these twin thresholds are not new - they date to the original Electricity Rules 2005. What the Supreme Court's 2023 Dakshin Gujarat Vij v. Gayatri Shakti Paper judgment added was a strict proportional-consumption test (about 1.96% consumption required per 1% ownership). The 2026 Amendment Rules replaced that unitary ratio with a collective test: each user's consumption counts toward the group's 51%, capped at their proportionate entitlement (26%+ owners are fully exempt from the cap) (Lexology/IndusLaw, Mar 2026).

The compliance flip-side: captive users are exempt from CSS and additional surcharge only while the plant passes annual captive verification. Fail the 51% consumption test in any year and CSS plus AS apply retroactively to that year's captive consumption; pending verification, no CSS applies if a proper declaration was filed.

What the charges do to landed tariff

Green Energy Open Access Rules 2022 set the frame: any consumer with 100 kW+ sanctioned load (no load limit for captive consumers) can buy renewable power, charges are limited to transmission, wheeling, CSS and standby, approvals are due in 15 days, and CSS cannot rise more than 50% above the year-of-grant level for 12 years (GEOA Rules text, Jun 2022).

Indicative North India stacking (FY 2025-26 orders, market compilations - verify against your state's current SERC order):

• Solar PPA: ₹3.50-4.20/kWh
• Transmission: ₹0.50-1.20/kWh | Wheeling: ₹0.40-0.90/kWh
• CSS: ₹1.20-2.50/kWh (Delhi ₹1.80-2.20; UP ₹1.50-2.10; Haryana ₹1.20-1.70) plus additional surcharge ₹0.30-1.40/kWh
• TPA landed: ₹6.2-7.5/kWh | Group captive (CSS exempt): ₹4.5-5.5/kWh

Worked examples show the stakes. In UP, UPERC's FY 2024-25 wheeling of ₹1.012/kWh plus ₹0.268/kWh transmission and voltage-slabbed CSS lands third-party solar at ₹4.0-6.5/kWh against an HT grid tariff of ₹7.93/kWh - with solar above 5 MW getting 50% wheeling/transmission exemption and 100% AS exemption. In Faridabad, a 500 kW factory choosing between DHBVN HT at ₹9.50/kWh, TPA at ₹6.90 and group captive at ₹5.10 leaves ₹13 lakh per year on the table by not structuring as captive at a 60,000-unit monthly load (market estimates; model with your own state's orders).

How to choose, in practice

• Choose TPA when: your load is below ~1 MW, you can't or won't hold power-plant equity, or you want a 10-15 year PPA with zero capex and zero compliance burden. Accept the CSS/AS premium as the price of simplicity.
• Choose group captive when: your sustained load supports 51% annual consumption of your entitled share, your board will hold SPV equity for the plant's life, and the CSS saving (₹1.5-2.5/kWh) justifies the compliance machinery. A ₹13 lakh/year saving on a single mid-size factory compounds to ₹3+ crore over a decade.
• Watch the 2026 change: consumption beyond your proportionate entitlement can be re-treated as supply from a generating company - attracting CSS + AS. Industry analysis flags a possible shift back toward single-user captive structures for buyers whose demand fluctuates (IndusLaw, Mar 2026).

Understand the underlying framework in our Green Energy Open Access hub guide, the 26% equity group-captive guide for North India, and compare states in our open-access comparison. For the accounting angle on PPAs, see our Ind AS 116 lease treatment of solar PPAs.

Frequently Asked Questions

What is the difference between third-party sale and group captive solar?

Ownership and surcharges. Third-party sale buys power from a developer's plant with no equity, so you pay cross-subsidy surcharge and additional surcharge on every unit. Group captive means each consumer holds at least 26% equity in the generating plant and the group consumes at least 51% of generation annually, exempting members from CSS and AS.

What is the 26% rule in captive solar generation?

The Electricity Rules require captive users to own at least 26% of the generating plant and to consume at least 51% of its aggregate annual generation, tested each financial year. The Electricity (Amendment) Rules 2026 modernised how the 51% is computed for groups - collectively, capped at each user's proportionate entitlement - but the 26%/51% thresholds themselves are unchanged since 2005.

How much cheaper is group captive than third-party open access solar?

Typically ₹1.5-2.5/kWh cheaper, because CSS and AS disappear. In NCR terms, third-party solar lands around ₹6.2-7.5/kWh while group captive lands around ₹4.5-5.5/kWh against HT grid tariffs of ₹7.9-9.5/kWh.

What happens if a captive plant fails its annual verification?

The plant loses captive status for that year and CSS plus additional surcharge apply to captive consumption - retroactively in respect of the failed year. Filing a correct declaration keeps CSS relief during pending verification, so documentation discipline is part of the structure's economics.

Did the 2026 Electricity Amendment Rules change group captive solar?

They changed the computation, not the thresholds. The Supreme Court's unitary qualifying ratio (~1.96% consumption per 1% ownership) is replaced by a group-level 51% test with per-user entitlement caps. Larger consumer groups find the test easier to meet; consumers whose offtake fluctuates beyond their entitlement face recharacterisation risk - which can push them back to single-user captive or third-party structures.