The petition arose from a dispute concerning the tariff payable under a 5 MW solar project commissioned under a PPA executed on 21.02.2014. Siwana Solar contended that although the Commission's earlier order dated 20.01.2016 had recognized tariff corresponding to a levelized tariff of ₹6.44/kWh, HPPC continued making payments at ₹5.68/kWh and failed to implement the tariff structure envisaged under the PPA. The generator therefore sought recovery of the differential amount along with interest.
HPPC opposed the petition by raising a preliminary objection that the matter was barred by the principles of res judicata and constructive res judicata. According to HPPC, disputes relating to tariff payments had already been resolved through settlement proceedings recorded in earlier litigation and the generator could not repeatedly agitate issues arising from the same cause of action.
HPPC further argued that the settlement was entered into after extensive litigation before multiple forums and had attained finality. It was contended that permitting fresh proceedings despite a concluded settlement would undermine certainty in regulatory and commercial arrangements and could potentially expose distribution utilities to recurring claims even after disputes had ostensibly been resolved.
While examining the issue, the Commission analysed the terms of the settlement relied upon by HPPC and the scope of the earlier proceedings. HERC ultimately concluded that the settlement primarily addressed outstanding dues payable up to the relevant period and did not amount to a waiver of future tariff claims arising under the PPA.
The Commission observed that the dispute raised in the present proceedings related to tariff payable for the period commencing from 01.04.2019 onwards and therefore constituted a distinct cause requiring adjudication on merits. Consequently, HERC rejected HPPC's objection that the petition was barred by res judicata.
Having held the petition maintainable, the Commission proceeded to examine the tariff entitlement of the generator and concluded that the order dated 20.01.2016, which had subsequently been upheld in appellate proceedings, continued to govern the parties. Accordingly, HERC held that Siwana Solar remained entitled to tariff corresponding to the levelized tariff of ₹6.44/kWh for the balance tenure of the PPA.
The Commission directed HPPC to calculate and release the differential tariff amount for energy supplied from 01.04.2019 onwards and further ordered payment of interest at 9.15% per annum from the respective due dates of invoices until actual payment.
Broader Regulatory Significance
The decision is likely to attract attention within the power sector as it addresses the interplay between settlement agreements and continuing tariff rights under long-term PPAs. While the Commission ultimately ruled in favour of the generator, the case also highlights concerns frequently raised by distribution utilities regarding the finality of settlements and the possibility of subsequent tariff-related claims arising after closure of earlier disputes.
For distribution licensees and procurers, the ruling underscores the importance of expressly addressing future tariff entitlements and waiver provisions while negotiating settlements, particularly in long-term renewable energy contracts where tariff obligations continue over extended periods.