Signed a PPA at a fixed tariff? A 2013 amendment won't rewrite it.

Gujarat Urja v. Renew Wind: The PPA that wouldn't bend

Gujarat Urja Vikas Nigam Limited, the state's bulk power procurer, signed 25-year power purchase agreements with wind generators at a fixed rate of Rs 2.64 per unit. The generators later wanted the tariff revised every year to match the annual Average Pooled Power Purchase Cost. The Gujarat Electricity Regulatory Commission and the Appellate Tribunal for Electricity agreed with them. The Supreme Court of India just said no. The stakes: the sanctity of every PPA signed under the REC mechanism, the finality of tariff terms, and the limits of regulatory intervention in a voluntarily negotiated contract.

The deal that was supposed to be final

Between 2011 and 2013, Gujarat Urja Vikas Nigam Limited (GUVNL) entered into power purchase agreements with several wind power developers, including Renew Wind Energy (Rajkot) Private Limited. The PPAs were executed under the Renewable Energy Certificate mechanism, governed by the Central Electricity Regulatory Commission's REC Regulations, 2010. The tariff was fixed at Rs 2.64 per unit for the entire 25-year term. Both sides signed. The generators began supplying power. GUVNL paid the agreed rate.

Then the wind generators moved an application before the State Commission. Their argument: a 2013 amendment to the REC Regulations — the Second Amendment, effective from 11 July 2013 — changed the framework. Under the amended regulations, they claimed, the tariff should be revised year-on-year to match the Average Pooled Power Purchase Cost (APPC). They wanted the State Commission to direct GUVNL to pay the difference for past years and revise the rate going forward.

The State Commission allowed the petition on 1 July 2015. It directed tariff revision to year-on-year APPC and held the order generic — applicable to all similarly placed wind power developers. GUVNL appealed to APTEL. The Tribunal dismissed the appeal on 6 December 2018. GUVNL then approached the Supreme Court, which initially disposed of the matter on 15 February 2019, granting liberty to seek review before APTEL. The review petition was dismissed on 24 July 2020. The matter came back to the Supreme Court under Section 125 of the Electricity Act, 2003.

What the generators argued

The wind developers had two main arguments. First, they said the PPA required prior approval of the State Commission under the Electricity Act, 2003 read with the Gujarat Electricity Regulatory Commission's regulations. Since that approval was never obtained, the PPA was not binding in its tariff terms. Second, they argued that the 2013 Second Amendment to the REC Regulations operated retrospectively. The amendment, they claimed, mandated that the tariff for REC-eligible projects must be the APPC, not a fixed rate. The PPA's fixed rate of Rs 2.64, they said, was inconsistent with the amended regulations and must yield.

They also pleaded coercion. The generators claimed that GUVNL, as a monopoly buyer, forced them to accept the fixed tariff. They said they had no choice but to sign the PPA at the rate dictated by the procurer.

What GUVNL said back

GUVNL's response was straightforward. The PPA was a valid contract voluntarily executed. No regulation required prior approval of the State Commission for renewable energy PPAs at the relevant time. The 2013 amendment was expressly prospective — it applied only to PPAs executed after 11 July 2013. The generators' PPAs were signed before that date. The fixed tariff was binding for the entire 25-year term.

On coercion, GUVNL pointed out that the generators had not pleaded any specific facts in their petition before the State Commission. No dates. No documents. No evidence of duress. The plea was a bare allegation, raised for the first time in arguments.

The Supreme Court's answer

The three-judge Bench — Justice Sanjay Kishan Kaul, Justice S. Ravindra Bhat (who authored the judgment), and Justice M.M. Sundresh — allowed GUVNL's appeal. The Court set aside the APTEL orders dated 6 December 2018 and 24 July 2020, and the State Commission order dated 1 July 2015.

The Court held four things.

First, no mandatory prior approval of the PPA by the State Commission was required. The Court examined the Electricity Act, 2003, particularly Sections 86(1)(a) and (b), which define the State Commission's functions. It noted that while the State Commission has the power to regulate tariff and issue licences, there was no specific regulation in Gujarat mandating prior approval of renewable energy PPAs at the time these agreements were signed. The PPA was valid and enforceable without such approval.

Second, the 2013 Second Amendment to the REC Regulations applied prospectively. The Court examined Regulation 5 of the REC Regulations, 2010, which sets out eligibility conditions for RECs. The amendment changed the tariff framework, but the Court held it could not affect PPAs executed before 11 July 2013. The tariff mutually agreed upon — Rs 2.64 per unit — remained valid for the PPA's duration.

Third, the plea of coercion was unsustainable. The Court applied the settled principle from Transmission Corporation of Andhra Pradesh Ltd v. Sai Renewable Power Pvt Ltd (2010) 8 SCR 636: a party setting up fraud, coercion, duress or undue influence must prima facie establish it by laying out material facts. Bare allegations without evidence are insufficient. The generators had not pleaded any specific facts in their petition. No evidence was led. The coercion plea failed.

Fourth, the State Commission and APTEL could not rewrite the tariff of a voluntarily executed PPA. The Court relied on its earlier decisions in Gujarat Urja Vikas Nigam Ltd v. Solar Semi-Conductors Power Ltd (2017) 14 SCR 115, Gujarat Urja Vikas Nigam Ltd v. EMCO Limited (2016) 1 SCR 857, and Gujarat Urja Vikas Nigam Ltd v. ACME Solar Technologies (Gujarat) Pvt Ltd (2017) 16 SCC 498. The consistent thread: a PPA validly executed binds both parties. The State Commission cannot substitute a new tariff at the instance of one party, especially where the Central Commission has clarified that the amendment is prospective.

THE PLAY: If you signed a PPA at a fixed tariff before a regulatory amendment, the amendment does not automatically rewrite your contract — unless the amendment expressly says it applies retrospectively and the PPA itself permits revision.

The doctrine that mattered

The case turned on three legal principles, none of them new, but all of them applied with precision.

Prospective application of regulations. The Court held that unless a regulation expressly states it operates retrospectively, it applies only to transactions entered into after its effective date. The 2013 Second Amendment did not contain any retrospective language. The generators' PPAs were signed before 11 July 2013. The amendment could not touch them.

Sanctity of contract in regulated markets. The Court rejected the argument that the State Commission's regulatory power under Section 86(1)(e) — promotion of renewable energy — allowed it to override the terms of a voluntarily executed PPA. The Commission's function is to regulate, not to rewrite. If parties freely agree to a tariff, the Commission cannot substitute its own view of what the tariff should be, unless the PPA itself provides for revision or the governing regulations mandate it.

Pleading and proof of vitiating factors. The Court reiterated that coercion, fraud, duress and undue influence are serious allegations. They must be specifically pleaded with material facts. A bare assertion in arguments — "we were forced to sign" — is not enough. The generators had not pleaded coercion in their petition before the State Commission. They had not led any evidence. The plea was rejected.

Why this matters in practice

For advocates, this judgment is a reminder that the Electricity Act, 2003 does not give State Commissions a roving mandate to rewrite PPAs. The Commission's power under Section 86(1)(e) to promote renewable energy is a guiding principle, not a licence to override contractual terms. If your client is a generator seeking tariff revision, you need to show either that the PPA itself permits revision, or that a retrospective regulatory amendment applies. You cannot rely on a bare policy argument.

For CFOs and founders in the renewable energy sector, the message is equally clear. A PPA is a contract. If you sign a fixed tariff for 25 years, you are bound by it — unless you have negotiated a revision clause. Regulatory amendments that come after your PPA will not save you, unless they expressly apply to existing agreements. The Supreme Court has now said this four times in the GUVNL line of cases. This is settled law.

For distribution licensees, the judgment is a victory for contractual certainty. If you have signed PPAs at fixed rates, you can resist demands for revision based on subsequent regulatory changes. But the judgment also carries a warning: if you are the monopoly buyer and you dictate terms, you must ensure the PPA is genuinely voluntary. A well-pleaded coercion case, backed by evidence, could still succeed.

The bottom line

If you signed a PPA before a regulatory amendment, the amendment does not rewrite your tariff — unless the amendment says it applies retrospectively and the PPA itself permits revision; plead coercion with facts, not just words; and remember that the State Commission cannot substitute its own tariff for the one you voluntarily agreed to.