Haryana Power Purchase Centre vs M/s Siwana Solar Power Projects Ltd. & Anr on 18 September 2026

JUDGEMENT

PER HON’BLE MRS. SEEMA GUPTA, OFFICIATING CHAIRPERSON

1. Present Appeal is preferred by Haryana Power Purchase Centre ("HPPC" or "the Appellant") assailing the Order dated 14.05.2026 ("Impugned Order") passed by the Haryana Electricity Regulatory Commission in Petition No. 78 of 2025 filed by M/s Siwana Solar Power Projects Ltd. ("Respondent No. 1" ) wherein, the Commission directed the Appellant to pay tariff of Rs. 6.44/kWh from 01.04.2019 onwards, along with differential tariff, interest and late payment surcharges to Respondent No 1. DESCRIPTION OF PARTIES

2. The Appellant, Haryana Power Purchase Centre (“HPPC”) is a joint forum created and owned by the Haryana State Distribution Licenses (“Discoms”) being the Dakshin Haryana Bijli Vitran Nigam Limited and the Uttar Haryana Bijli Vitran Nigam Limited, with a mandate to arrange/

procure economical, reliable and cost-effective power including renewable and non-conventional sources to meet the Universal Service Obligation and demand of electricity. HPPC, constituted under orders of the Government of Haryana vide notification dated 11.04.2008, acts as a single buyer model for performing the function of arranging power on behalf the Discoms.

3. Respondent No. 1, M/s Siwana Solar Power Projects Ltd. (hereafter referred as “Respondent No 1/ Siwana"), is a company engaged in the generation of solar power from a 5 MW Solar PV Crystalline Power Plant situated at Village Mithi, Tehsil-Siwani, Distt. Bhiwani, Haryana.

4. Respondent No. 2, the Haryana Electricity Regulatory Commission is (hereafter referred as "HERC/State Commission"), the State Electricity Regulatory Commission for the State of Haryana, constituted and functioning under the provisions of the Electricity Act, 2003. BACKGROUND

5. HPPC and Siwana executed a PPA on 21.02.2014 for purchase of solar power from Siwana's 5 MW plant for 25 years from the date of Commissioning. The Clause 4.1 of the PPA executed between the parties stipulates that the applicable tariff shall be the lowest of : (a) the generic tariff of Rs. 7.94/kWh (FY 2013-14) or Rs. 7.58/kWh (FY 2014-15) depending on the commissioning date; (b) the lowest tariff quoted and accepted in the first long-term competitive-bidding tender to be floated by HPPC by 31.12.2015; or (c) the lowest tariff quoted and accepted in the

first long-term reverse-bidding tender to be floated by HAREDA by 31.12.2015.

6. On 16.04.2014, HPPC floated NIT No. 51 for procurement of 50 MW of solar power on the long-term basis. The lowest tariff discovered was Rs. 6.44/kWh and letter of Intent were issued to successful bidders on 27.03.2015 and PPAs were executed with four developers namely, M/s JBM Solar Power Pvt. Ltd; M/s Subhash Infra Engineers Pvt. Ltd.; M/s Utrecht Solar Pvt. Ltd.; and M/s Balarch Solar for a cumulative capacity of 23 MW.

7. The Respondent No.1- Siwana filed a Petition being Case No. HERC/PRO-51 of 2014 mainly seeking amendment in the PPA, signed with Appellant to substitute the competitive bidding tariff to generic tariff as decided by the State Commission. However, State Commission vide its order dated 22.07.2014, dismissed the said petition and held that tariff to be payable to the generator as per the provisions of the PPA.

8. State Commission in its generic tariff order dated 13.08.2014 determined levelised tariff at Rs 7.45 /kWh (with first year tariff as Rs 9.93/kWh) for solar power projects commissioned in FY 2014-15. Siwana’s Generation Plant was commissioned on 31.12.2014 and it raised its first bills at the generic tariff of Rs. 9.93/kWh as determined by the State Commission. However, HPPC paid at Rs. 6.44/kWh, as per Clause 4.1(b) of the PPA. Thereafter, the Respondent no.1-Siwana filed the case No. HERC/ PRO-24/2015 seeking the generic tariff of Rs. 7.45/kWh (Levelized) as decided in HERC tariff order dated 13.08.2014. HERC vide Order dated 20.01.2016 ("the 2016 Order"), rejected the petition filed by

the Respondent No.1 and held that Siwana was bound by the terms of the PPA and entitled only to Rs. 6.44/kWh, being the lowest tariff discovered through competitive bidding guidelines for renewable energy under Section 63 of the Electricity Act, 2003.

9. PPA signed by Appellant with four developers as mentioned above, submitted by Appellant for approval of State Commission, was rejected by the State Commission vide its orders dated 12.09.2016 & 04.10.2016 holding that competitive bidding process was not in compliance with competitive-bidding guidelines for renewable energy under Section 63. Thereupon, the four developers filed the appeals before this Tribunal (Appeal Nos. 278/2016 & 307/2016) challenging the rejection by the HERC. This Tribunal vide order interim order dated 13.12.2016 and 29.03.2017 allowed these developers to supply power at Rs. 5.68/kWh on an interim basis. Thereafter, vide order dated 09.03.2018 the Appeals (Nos. 278/2016 & 307/2016) were allowed in favour of four developers and held that PPAs of all four developers to be approved by HERC at the tariff of Rs. 5.68/kWh being the CERC-determined generic tariff for FY 2016-17. The same tariff i.e., Rs. 5.68/kWh was approved by the HERC. This Judgment was carried to the Hon'ble Supreme Court in Civil Appeal Nos. 5962, 5869, 5843 and 7296 of 2018 by four developers. Subsequently, Supreme Court on 10.10.2023 dismissed the said Civil Appeal upholding the Tribunal’s judgement.

10. The Appellant herein applied a tariff of Rs 5.68/kwh from March 18 onwards on the invoices raised by Siwana. Siwana approached the State Commission vide Case No. HERC/PRO-5 of 2019 for such reduction in tariff. State Commission vide order dated 10.05.2019 applied an interim

tariff corresponding to levelised tariff of Rs 5.68/kwh for Siwana’s project subject to the outcome of the Civil Appeals pending before the Supreme Court.

11. The Respondent No.1/Siwana had also filed a separate Appeal (No. 150 of 2016) against the order passed by State Commission dated 20.01.2016 (2016 Order), which was dismissed by this Tribunal vide Judgment dated 27.05.2019 ("the APTEL 150 Judgment"), affirming the 2016 Order of State Commission.

12. During the pendency of the Civil Appeals, the parties (Appellant & Respondent No 1-Siwana) undertook a reconciliation. The Respondent No.1 vide letter dated 17.08.2020, proposed a settlement of pending dues "to put an end to the prolonged litigation", subject to the outcome of the pending Civil Appeals, and accepted the reconciled figure of Rs. 48,38,038 vide letter dated 21.08.2020 and confirmed acceptance in full and final settlement vide letter dated 22.08.2020 and withdrew the petition ( No 8/2020). HERC recorded the withdrawal vide Order dated 29.09.2020 ("the PRO-8/2020 Order").

13. Respondent No.1 filed the Review Petition No. 7 of 2022, for the Review of State Commission Order dated 29.09.2020, which was dismissed by State Commission on 14.09.2022. The Siwana preferred Appeals No. 411/2022 and DFR No. 217/2023 before this Tribunal challenging the orders dated 29.09.2020 and 14.09.2022, which were dismissed by this Tribunal by common Judgment dated 21.08.2023, affirming the settlement. Respondent No 1, had challenged the common order dated 21.08.2023 passed by the Tribunal before the Supreme Court

in Civil Appeal Diary No. 44243 of 2023, which was dismissed vide order dated 02.01.2024.

14. In April 2024, the Respondent No.1 filed Petition No. 26 of 2024 before the State Commission for implementation of the 2016 Order and payment at Rs. 6.44/kWh along with differential amount over Rs. 5.68/kWh, the same was dismissed by State Commission vide Order dated 12.11.2024 on the principle of 'Res-judicata'.

15. In August 2025, the Respondent No.1 had filed a fresh Petition bearing No. 78 of 2025. The State Commission vide the Impugned Order dated 14.05.2026, allowed a tariff of Rs 6.44/kwh for Siwana’s Project. Being aggrieved by the same, the Appellant - HPPC has preferred the present Appeal. SUBMISSIONS URGED ON BEHALF OF APPELLANT

16. The Appellant submits that the Impugned Order is contrary to the settled principles of res judicata, finality of litigation, judicial discipline and judicial propriety, inasmuch as it amounts to re-opening and re- adjudicating an issue which is already been decided by the HERC in its un-challenged Order dated 12.11.2024 passed in Petition No. 26 of 2024.

17. It submits that the prayers sought in Petition No. 78 of 2025, in which Impugned Order is passed, are identical to those in Petition No. 26 of 2024, as well as earlier petitions including Petition No. 05 of 2019 decided by HERC on 10.05.2019, and Petition No. 08 of 2020 which came to be withdrawn on 29.09.2020 including its Review Petition bearing number 07

of 2022 dismissed on 14.09.2022 and followed by Appeal being DFR No. 217 of 2023 dismissed on 21.08.2023 by this Tribunal and further appeal in Supreme Court, which also came to be dismissed vide order dated 02.01.2024. Therefore, it is impermissible for the State Commission to pass Impugned Order in contravention of its earlier Order dated 12.11.2024, 10.05.2019 and 29.09.2020 read with order 14.09.2022 which have attained finality.

18. The Appellant further submits that Respondent No. 1 voluntarily accepted a sum of Rs 48,38,038 as full and final settlement of its claims based on the tariff of Rs 5.68/kWh, and consequently withdrew Petition No. 08 of 2020. The said settlement order was subsequently challenged before this Hon’ble Tribunal and Hon’ble Supreme Court, however same has been upheld, thereby attaining finality. Respondent No. 1, is, therefore, barred by the principles of waiver, acquiescence and estoppel from seeking to reopen the settled dispute. Further, the attempt in the Impugned Order to reopen the consent/compromise decree is barred in terms of Order XXIII Rule 1 of the Code of Civil Procedure, 1908.

19. The Appellant submits that the petition filed by Respondent No. 1 is ex facie time-barred and therefore liable to be set aside as per the law laid down in “AP Power Coordination Committee v. Lanco Kondapalli Power Ltd”; (2016) 3 SCC 468. The claim of Respondent No 1 for Rs 6.44/kWh stems from the earlier Order dated 10.05.2019 passed by HERC (Petition No 05 of 2019), wherein HERC directed payment at Rs 5.68/kwh and accordingly the three-year limitation period expired in May 2022. State Commission, in the Impugned Order, has erred in holding that each

monthly invoice gives a fresh cause of action, as the prayer pertains to the determination of tariff.

20. The Appellant submit that Clause 4.1 of the PPA, the applicable tariff is the lowest tariff discovered under NIT No. 51. After the full course of litigation culminating in the “JBM Solar Judgment” from Orders dated 12.09.2016 & 04.10.2016 passed by HERC; Orders dated 13.12.2016, 29.03.2017 and 09.03.2018 passed by this Hon’ble Tribunal; and Supreme Court's order dated 10.10.2023 passed in Civil Appeal Nos. 5962, 5869, 5843 and 7296 of 2018. , the final tariff approved under NIT No. 51 stands at Rs 5.68/kWh. Consequently, the observations in the APTEL judgement in appeal 150 of 2016 27.05.2019 mentioning Rs 6.44/kWh stand impliedly overruled. (“S.E. Graphites Pvt. Ltd. v. State of Telangana & Ors” (2020) 14 SCC 521).

21. Appellant further submits that granting Respondent No. 1 a tariff of Rs 6.44/kWh creates an anomalous situation where two different tariffs exist under the same competitive bidding process. The distinction between "past dues" and "prospective tariff" created by the HERC in the Impugned Order is artificial, directly violating HERC's own Order dated 12.11.2024 and Respondents No.1 explicit admission in its letter dated 17.08.2020.

22. Appellant further disputes the directions awarding differential tariff, interest at 9.15% per annum and late payment surcharge and carrying cost are legally unsustainable. Furthermore, the burden of carrying costs due to delay in filing cannot be imposed onto the as held in the judgements in “Maharashtra State Electricity Distribution Co. Ltd. v. MERC”, in Appeal No. 70 of 2007 ; “Torrent Power Ltd v. Gujarat Electricity

Regulatory Commission” in Appeal No. 147, 148 and 150 of 2013; “Paschim Gujarat Vij Company Ltd and Ors v. Gujarat Electricity Regulatory Commission” in Appeal No. 45 of 2014. Further, a party, which causes the delay, cannot then claim interest for such period as settled in “Kanwar Singh and Ors. vs. Union of India (UOI)”; 2005 (82) DRJ 397, 120 (2005) DLT 348 and “Budh Ram Vs. Union of India (UOI) and Ors”; 2011 SCC Online Del 1192.

23. Appellant submits that even after passing the judgment dated 27.05.2019, the Respondent No. 1 acknowledged Rs 5.68/kWh as the prevailing competitive rate by seeking its implementation in Petition No. 08 of 2020 and its settlement vide letter dated 17.08.2020 subject to the outcome of pending Civil Appeals before the Supreme Court; having so agreed, it cannot now approbate and reprobate after those appeals were dismissed on 10.10.2023. SUBMISSIONS URGED ON BEHALF OF RESPONDENT No.1-SIWANA

24. Respondent No.1 submits that the impugned order merely enforces the HERC Order dated 20.01.2016 passed in HERC/ PRO-24 OF 2015 in which it was held that Siwana (then Respondent No. 2) is entitled to tariff of Rs. 6.44 kWh and directed HPPC to compute year to year tariff corresponding to the said levelized tariff and this Tribunal’s Judgment dated 27.05.2019 passed in Appeal No, 150 of 2016, which conclusively upheld and determined the tariff at Rs 6.44/kWh. Since, the Appellant never challenged these decisions, they have attained finality and cannot be indirectly nullified. As per PPA Clause 4.1, the tariff shall be the lowest discovered tariff through competitive bidding and therefore it is submitted

that the contractual terms, regulatory orders and judicial decisions are binding upon the parties and the Appellant cannot utilize an interim order as a permanent shield to unilaterally rewrite a concluded PPA and inflict severe ongoing monetary loss upon the generating company.

25. It is further submitted that it is well settled position of law that once a judicial determination attains finality, the same cannot be indirectly nullified through subsequent administrative action, selective interpretation, or continued non-compliance and places its reliance upon “Damodar Valley Corporation versus West Bengal State Electricity Distribution Company Limited and Ors.”; , “Union of India v. S.P. Sharma”;, (2014) 6 SCC 351, “Delhi Electricity Regulatory Commission versus Tata Power Delhi Distribution Limited” (Civil Appeal 6388 of 2025).

26. The Respondent No.1 further submits that the reduced tariff of Rs 5.68/kWh stems from independent proceedings involving four other developers with materially different project parameters and PPA dates, to which Respondent No. 1 was not a party. The Supreme Court’s Order dated 10.10.2023 dismissing those developers' appeals did not modify Respondent No. 1’s legally vetted Rs 6.44/kWh tariff. Permitting payment at Rs 5.68/kWh was strictly an interim arrangement pending the Civil Appeals and never substituted the final tariff. It is further submitted that the settlement dated 29.09.2020, wherein former director of the Respondent No 1 filed an affidavit accepting 'full and final settlement' as Rs.48,38,038/- is with respect to the outstanding dues of the Respondent No. 1 till September, 2019 on 18/09/2020 subject to the outcome of Civil Appeal bearing Nos. 5962, 5843, and was expressly confined to the reconciliation of past arrears up to March 2019. A settlement of past dues

does not extinguish future contractual rights or override binding judicial determinations.

27. The Respondent No.1 submits that the Appellant's reliance on res judicata is misconceived, as continuous underpayment despite a finalized tariff creates a recurring and continuing cause of action. Because the settlement was restricted to the period ending March 2019, res judicata cannot bar the enforcement of the Rs 6.44/kWh tariff from April 2019 onwards. Judicial determinations that have attained finality must be implemented and cannot be bypassed, as supported by the principles laid down in “Power Company of Karnataka Ltd. v. Udupi Power Corporation Ltd” in Appeal 10 of 2020. DISCUSSION AND ANALYSIS

28. Heard Mr. Nikhil Nayyar, learned senior counsel for the Appellant, Mr. Senthil Jagadeesan learned senior Counsel for the Respondent- Siwana, perused the written submissions filed by the parties, Impugned Order and other documents on record. The issue pertains to applicability of Rs 6.44/kWh for the Siwana’s generation project as held in the Impugned Order, while Appellant has contended that when competitively discovered tariff of Rs 6.44/kWh has been substituted by a tariff of Rs 5.68/kWh, in terms of PPA, the tariff of Rs 5.68 /kWh gets applicable for Siwana’s Project. Appellant has also raised the issue of limitation and Res- judicata, impact of settlement reached between the parties. All these issues are deliberated in following paragraphs. The case has a chequered history, and considering that various previous orders of State Commission and Judgements of this Tribunal and Hon’ble Supreme Court have been

relied upon by both the parties, it would be of relevance to refer to the observation contained in various orders/judgements related to the referred project and provisions of PPA PPA Dated 21.02.2014 between Appellant & Siwana “4.1. Sale of Energy by Company: The HPPC shall purchase and accept all energy made available at the Delivery point from the Company's facility, pursuant to the terms and conditions of this agreement as per the amount claimed by the Company for the energy delivered for sale (including captive/ auxiliary consumption of Solar Power generated less the energy imported by IPP) of electricity generated from Solar PV crystalline Power Plant valid for a period of 25 years during the Billing period at the following tariff whichever is the lowest rate out of the following three options:

a) Generic tariff decided by HERC i.e. Rs. 7.94 for FY 2013-14 in case the plant is commissioned before 31.3.2014 or Rs. 7.58 per unit for FY 2014 15 in case the plant is commissioned by 30.6.2014

b) The lowest tariff quoted and accepted in the first long term tender for purchase of solar power through competitive bidding to be floated by HPPC till 31.12.2015.

c) The lowest tariff quoted and accepted in the first long term tender for purchase of solar power through reverse bidding to be floated by HAREDA till 31.12.2015., as per solar policy of Govt. of Haryana.” ……  State Commission Order dated 22.07.2014 (Case No HERC/PRO- 51 of 2014)

29. Respondent No 1-Siwana had filed the above petition seeking amendment of Clause 4.1 of PPA seeking applicability of Generic tariff to be determined by the State Commission for their project and extension of time for completion of Project. While State Commission allowed the extension of time for completion of project till October 2014, however amendment in PPA for adoption of generic tariff was not accepted by the

State Commission, and it has been held that the PPA signed between the parties has already been approved by the State Commission and at this stage, it is not open for the Petitioner ( i.e. Siwana) to question clause 4.1 of PPA or any other terms and conditions of concluded PPA.  State Commission Order dated 20.01.2016 (Case No HERC/PRO-24 of 2015).

30. After Commissioning of their Project on 31.12.2014, Siwana raised the first bill for sale of power to Appellant on 11.03.2015 ( for the period 31.12.2014 to 11.03.2015) and 01.04.2015 ( for the period 11.03.2015 to 01.04.2015) at a tariff of Rs 9.93/kwh in terms of Generic Tariff Order dated 13.08.2014 of the State Commission. Appellant herein, however, paid these bills @ Rs 6.44/kWh, the main issue in the present Appeal, besides other deductions, which are not required to be deliberated in the present Appeal.

31. The State Commission, in this order, referring to its earlier order dated 22.07.2014, observed that said issue has already been decided, which is not challenged by any party and has therefore attained finality and accordingly tariff payable shall be in terms of the PPA signed, and levelized tariff of Rs 6.44/kwh was affirmed for Siwana’s Project, relevant para is extracted hereunder:- “This Order of this Commission has not been challenged by any parties and, as such, has attained finality. In view of the above, the issue regarding the amendment of Clauses 2.1.41 and 4.1 of the PPA relating to applicable Tariff needs no further adjudication and the tariff payable to the generator by HPPC shall be as per the provisions of the PPA.

Further, during the course of arguments, the Commission suggested that the year to year tariff should be worked out corresponding to the levelised tariff of Rs. 6.44 per unit and the year to year tariff so worked out be paid to the Petitioner by Respondent No. 1. This proposal was agreed to by the Respondent No. 1. Accordingly, the Commission directs Respondent No. 1 to work out the year to year tariff for 25 years corresponding to the levelised tariff of Rs. 6.44 per unit and pay the tariff to the Petitioner so worked out for the relevant year.”

32. Respondent No 1-Siwana challenged this order before this Tribunal vide Appeal 150 of 2016, seeking levelised tariff as per State Commissions Order dated 13.08.2014 instead of Rs. 6.44/kWh finalized in this order.  This Tribunal Judgement dated 09.03.2018 ( Appeal No 278 & 307 of 2016)

33. Separately, the PPA signed by the Appellant with four developers, (subsequent to competitive bidding) with tariff @ Rs 6.44/kWh was not approved by the State Commission, vide its orders dated 12.09.2016 & 04.10.2016. State Commission held that competitive bidding process was not in compliance with competitive-bidding guidelines for renewable energy under Section 63. State Commission in this order, however, observed that these generators have an option to supply electricity at a tariff being discovered for future projects to be established @ Rs. 5.68 /kWh. Against the said order, four developers filed Appeals (278/2016 & 307/2016). This Tribunal vide its interim order dated 13.12.2016 and 29.03.2017 allowed these developers to supply power at Rs. 5.68/kWh on an interim basis. Thereafter, this Tribunal passed final order dated 09.03.2018 and in Paragraphs 12 observed as under:-

“12. After having a careful examination of all the aspects brought before us on the issues raised in the Appeals and submissions made by the Respondents and the Appellants for our consideration, our observations are as follows: -

a) The present cases pertains to the decision of the State Commission vide Impugned Order rejecting the PPAs entered into between the Appellants and the Respondent No. 2 pursuant to competitive bidding process initiated by the Respondent No. 2 for procurement of solar power.

b) This is a case where the Impugned Order of the State Commission has been based on the casting vote of its Chairman and Member has given its dissenting order by disagreeing with the decision of the Chairman of the State Commission. The Chairman of the State Commission had also pronounced its Order even before the Order of the Member of the State Commission was ready indicating that there was lack of proper consultations between the two.”………….

34. This tribunal after extracting the findings in impugned Order as well as the findings of the Member of the State commission in the dissent order, observed as under: - “(iii) We observe that the whole issue of power purchase/PPAs is hovering around the application of Section 63 of the Act which says that the Appropriate Commission shall adopt the tariff if such tariff has been determined through transparent process of bidding in accordance with the guideline issued by the Central Government. In the present case, actually no guidelines/ SBD have been issued/notified by Gol at that point of bidding and till completion of the bid process and even up to the Impugned Order date. The Respondent No. 2 initiated the bidding process on draft guidelines only and informing the State Commission the same at a later stage when the bidding process was completed and approached the State Commission for the approval of the PPAs it entered into with the selected bidders. The State Commission has also not gone into the details by checking whether such guidelines /SBD has been notified by Gol. The State Commission vide letter dated 8.8.2014 has also given go ahead for the bidding process to the Respondent No. 2. The relevant extract of the letter is reproduced below:……..

“iv) After going through the various aspects of the case we find that both the State Commission and the Respondent No. 2 had made mistake. The Respondent No. 2 making its bid process on non- existent guidelines/SBD and the State Commission passing the Impugned Order on premise of Section 63 as if guidelines/SBD existed. The issue is between the State Commission and the Respondent No. 2. The sufferers are the Appellants who have already installed the solar power plants based on Lol issued and PPAs signed with them for no fault of them.” …………… …………. “ (vi) In view of the foregoing discussions, we observe that the whole exercise of the bidding was premised and based on the wrong notion that competitive bidding guidelines/ SBD do exist which was not true. Solar Power purchase was initiated by the Respondent No. 2 based on repeated directions from/observations of the State Commission in various ARR orders as well as in the letter dated 8.8.2014. It is also observed that the Respondent No. 2 has followed the bidding documents which it had submitted to the State Commission and the State Commission too has given go ahead with the bidding process. Negotiations too were carried out by the Respondent No. 2 in accordance with the bidding documents. PPAs too were signed after completion of the bidding process and the Appellants have already set up the solar power plants. The State Commission in the Impugned Order has also allowed the Respondent No. 2 to procure power from these plants based on the tariff determined by CERC for FY 2016-17, the year in which these plants were commissioned. This Tribunal as an interim allowed the said CERC tariff of FY 2016-17 to the Appellants.

(vii) The basic issue which merits consideration is that there was a competitive bid process initiated by the Respondent No. 2 for selection of solar power developers to supply solar power to the Respondent No. 2. Irrespective of whether such competitive bid process was undertaken under Section 63 of the Act based on the guidelines issued by Gol or not, the fact that such a competitive bid process was initiated, solar power developers were invited to participate and give their bids and the PPA was finalised between the Respondent No. 2 and the selected bidders cannot be denied. Further, the State Commission was also informed of the bidding process being undertaken by the Respondent No. 2 and the State Commission did not stop the process at the relevant time by stating that Respondent No. 2 should wait until the guidelines are issued

under Section 63 of the Act or on the ground that there exists guidelines of Gol which need to be followed. The entire process was allowed to be implemented without the State Commission exercising its regulatory powers to either stop or otherwise provide the course of action to be adopted for Respondent No. 2 to complete the bidding process. It is not for the State Commission to have raised all these issues at a later stage when the approval of PPAs with tariff discovered and negotiated downwards was placed. The Appellants have referred to the procurement of power in another case (M/s Siwana Solar Power Projects) wherein the State Commission has approved the PPA with a tariff of Rs. 6.44/kWh. However, there is no allegation in regard to the issue of guidelines being followed or not in the said decision.

(viii) Further, the PPA executed by the Respondent No. 2 with M/s Siwana Solar Power Projects on 21.2.2014 was prior in point of time as compared to the PPAs with the Appellants and the approval was granted vide order dated 20.1.2016. The PPAs in the present case were executed on a subsequent date during June 2015 and the approval to the PPAs was sought from the State Commission on 16.7.2015. The price of the solar panels are falling progressively as indicated by various bidding process cannot be ignored. At the same time the absence of finalised guidelines by Gol cannot be considered as a ground for not approving the PPAs, particularly in the context of Section 63 of the Act which states that the bidding has to be "in accordance with the guidelines" in case of Energy Watchdog v. CERC decided by the Hon'ble Supreme Court on 11.4.2017 in Civil Appeal Nos. 5399-5400 of 2016.” ………… ……..

(ix) Considering the circumstances of the case equitably and the fact that the Solar Power Projects have been established by the Appellants and in terms of Section 86 (1) (e) of the Act, the power generation from renewable sources of energy need to be promoted, it would be appropriate to approve the PPAs between the Appellants and the Respondent No. 2 for procurement of solar power at the tariff of Rs. 5.68/kWh (without accelerated depreciation) as allowed in the interim Orders dated 13.12.2016 and 29.3.2017 of this Tribunal.”

35. This Tribunal in this judgment after going through the order impugned in these appeals, as well as dissent order and considering all the circumstances, approved the procurement of power from these four

developers ( so selected through competitive bidding) at a tariff of Rs. 5.68 /KWh. It is further to note that when deliberations were held with respect to price applicable to the projects discovered through competitive bidding, no dispute has been raised by any party with respect to noting of tariff of Rs. 6.44 /kwh for the Siwana Project in this Judgment, for which PPA was signed on 21.02.2014 and has already been approved by State Commission. This Judgment was challenged before the Hon'ble Supreme Court by the four developers, in Civil Appeal Nos. 5962, 5869, 5843 and 7296 of 2018, which was dismissed by Hon’ble Supreme Court vide its order dated 10.10.2023. Our attention has not been brought to the fact if the above judgement of this Tribunal has been challenged with respect to mentioning of tariff of Rs 6.44/kwh for Siwana Project, while the same tariff was a matter of dispute in these appeals for the four developers and by the order of this Tribunal dated 09.03.2018, a tariff of Rs 5.68 /kwh was made applicable for these four developer’s projects.  State Commission Order dated 10.05.2019 ( case No HERC/PRO-5 of 2019).

36. Subsequent to passing of judgement of this Tribunal dated 09.03.2018, Appellant-HPPC started paying the tariff @ Rs 5.68 /kWh to the Respondent No 1- Siwana’s generation Project. Siwana filed petition No. 5 of 2019, reiterating entire sequence of events and again praying for Generic Tariff for its project since the price discovered in competitive bidding became ab-initio and could not be considered under clause 4.1 of PPA. Siwana also disputed the tariff of Rs. 5.68/kWh made applicable for its project as the said tariff is applicable for projects commissioned in FY 2016-17, whereas its project had been commissioned earlier. State Commission took note that since applicability of generic tariff to Siwana

project was pending adjudication before this Tribunal ( Appeal No 150 of 2016 ), held that it was not open for the Petitioner to re-agitate this issue before this Commission. State Commission held as under-: “13. In view of the above discussions, the Commission observes that HPPC was within its rights to settle the energy bills generated by the Petitioner at Rs. 6.44/kWh. The only deviation taken by HPPC is regarding non determination of year to year tariff corresponding to the levelized tariff of Rs. 6.44/kWh, as directed by the Commission in its Order dated 20.01.2016. In this regard, the submission of HPPC that the tariff rate of Rs. 6.44/kWh was discovered through bidding and it was not possible to work back year to year tariff of the same, has been considered by the Commission and the Commission is of the considered opinion that in case of difficulty in the implementation of the Order of the Commission, the appropriate remedy available with HPPC was to seek review from the Commission of its Order. However, presently, that the discovered tariff of Rs. 6.44/kWh has been replaced by Rs. 5.68/kWh, HPPC may refer to the Annexure 5A of the Hon'ble Central Electricity Regulatory Commission's Order dated 29th April, 2016 in Petition No. SM/03/2016 (Suo-motu) wherein year to year tariff corresponding to the levelized tariff of Rs. 5.68/kWh has been worked out by the CERC. Hence, as an interim arrangement, the year to year tariff shall be payable subject to the judgement of Hon'ble Supreme Court in Civil Appeal nos. 5962, 5869, 5843 7296 of 2018.” This order of State Commission was not challenged by any party.  This Tribunal Judgement dated 27.05.2019 ( in Appeal No 150 of

37. Siwana had challenged the order of State Commission dated 20.01.2016 (in case No 24 of 2015) fixing the tariff @ Rs 6.44 /kWh, stating that since the bidding process vide which such tariff was obtained is non- est and a nullity, Siwana was entitled to the tariff as determined by State

Commission vide the tariff order dated 13.08.2014, besides other issues which are not disputed in the present appeal. After taking note of the submissions of Siwana and HPPC, this Tribunal rejected the applicability of Generic tariff Order for the Siwana Project and upheld the order impugned in this Appeal with respect to applicability of a tariff of Rs 6.44 /kWh for Siwana’s Project. Relevant paragraph of the judgement is extracted hereunder:- “7.5 We have considered the rival contentions of the learned counsel for the Appellant as well as learned counsel for Respondent No.2. It is relevant to note that in pursuance of the order dated 05.11.2013 of the Respondent Commission, the Appellant had to start generation of power by 31.03.2014, however, the commissioning of the solar project by the Appellant got delayed and finally the project got commissioned only on 31.12.2014. The State Commission while passing the final order dated 21.09.2014 vide which the commissioning of the solar project was extended till 31.12.2014, stipulated that the applicable tariff for the Appellant would be the tariff as determined by the Commission for FY 2014-15. While learned counsel for the Appellant contend that the tariff of Rs.6.44/kWh discovered by HPPC through a competitive bidding is not applicable to the Appellant due to the fact that the said bidding was declared null and void by the State Commission and as such the levalised tariff of Rs.745/kWh determined by the Commission for FY 2014-15 for solar power plants should apply. On the other hand, learned counsel for the Respondent submits that as per terms of the PPA, the Appellant is entitled for the tariff lowest of the three alternatives provided in Clause 4.1 of the PPA. Learned counsel for the Respondent also contends that the competitive bidding process undertaken by HPPC has been held as valid by this Tribunal vide its judgment dated 09.03.2018 in A.No.278 of 2016 in case of JBM Solar Private Limited. In fact, the State Commission had not approved the bidding process and the PPAs only on account of the deviations not being approved by it and not due to any other reasons. As per the directions of this Tribunal, the State Commission approved the PPAs signed between HPPC and the selected bidders. As such the contentions of the Appellant that the bidding process was illegal is not correct. While taking note of the judgments of this Tribunal and Hon'ble Gujarat High

Court, it emerges that the bidding process undertaken by HPPC was legally sustainable and as such the lowest tariff discovered in the process has to be applied to the case of the Appellant i.e. the tariff at Rs.6.44/kWh. In view of these facts, we are of the opinion that the State Commission has allowed the tariff applicable to the Appellant's solar project appropriately and the impugned order does not suffer from any legal infirmity. Hence, interference from this Tribunal is not called for.” It is evident from the above that while upholding the applicability of Rs 6.44/kwh for Siwana’s Project, this Tribunal took note of the issues pertaining to referred competitive bidding process as also deliberated in detail in the Judgment dated 09.03.2018, and held that it is incorrect to hold that competitive bidding process undertaken by HPPC is not legal. It appears that HPPC, though disputed the applicability of Generic Tariff Order to Siwana's project, it did not plead for the applicability of Rs 5.68 /kwh tariff as made applicable for four developers for Siwana’s Project This Tribunal upheld the Order dated 20.01.2016, passed by the State Commission. We have been informed that this judgement has not challenged by any party.  State Commission Order dated 29.09.2020 ( Case No HERC/PRO-8 of 2020).

38. Siwana had filed a petition before State Commission with regard to implementation of State Commission Order dated 20.01.2016 and 10.05.2019 read along with this Tribunal Judgement dated 27.05.2019 and for refund of Rs 44,55,268 said to have been deducted illegally as interest while making payment in August 2018 @ Rs 6.44/kwh. We take note that during the hearing of the Petition on 21.07.2020, recording the willingness of HPPC to settle the pending payment, State Commission gave an

opportunity for mutual settlement within four weeks. The Siwana and Appellant herein reached for mutual settlement and Siwana accepted the mutually agreed payment amount vide letter dated 22.08.2020 and State Commission taking cognizance of these developments, allowed Siwana to withdraw the petition.

39. Though, Siwana subsequently sought the review of the Order dated 29.09.2020 citing unauthorized settlement by their Director, State Commission rejected the allegations of fraud and coercion as unsubstantiated and dismissed the review petition vide its order dated 14.09.2022. Subsequent to dismissal of Review, Siwana preferred an Appeal (DFR No 217 of 2023) against the order dated 29.09.2020 of the State Commission, however the Appeal was dismissed by this Tribunal vide its Judgment dated 21.08.2023 and challenge to this Judgement in Supreme Court vide Civil appeal bearing diary no 44243 of 2023 was dismissed by Hon’ble Supreme Court vide its Judgement dated 02.01.2024. Supreme Court Order dated 10.10.2023 in Civil Appeal Nos 5962,5869, 5843 & 7296 of 2018

40. The Hon’ble Supreme Court vide its judgement dated 10.10.2023 dismissed the civil appeals filed by four Developers, thereby affirming this Tribunal's Judgment dated 09.03.2018  State Commission Order dated 12.11.2024 (Case No HERC/Petition NO 26 of 2024)

41. Siwana filed another petition before State Commission reiterating the entire history of litigation with respect to their project and considering the Judgement of Supreme Court dated 02.01.2024, submitted that the issue with respect to dues payable by the HPPC to them till Sept 2019 stood settled, however prayed for implementation of directions passed by State Commission in its tariff dated 20.01.2016 and to direct the Respondent- HPPC to pay tariff to them at Rs. 6.44 /kWh and pay for the differential for tariff deficit between Rs. 5.68 /kWh and Rs. 6.44 /kWh.

42. State Commission vide its Order dated 12.11.2024, referring to the prayers made by Siwana with respect to payment of tariff of Rs 6.44/kWh in various petitions filed by them held that the issue stand resolved by the orders of this Commissions dated 29.09.2020, 14.09.2022, decisions of this Tribunal in the judgement dated 21.08.2023 and Supreme Court order dated 02.01.2024. The issue has attained finality and principle of ‘Res- Judicata’ is applicable and the petition of Siwana was dismissed. Admittedly, no appeal was filed against the said order of the State Commission Impugned Order dated 14.05.2026 (Case No HERC/Petition No. 78 of

43. Siwana filed the instant petition praying for the tariff of Rs 6.44/kWh for its project instead of Rs. 5.68/kWh being paid by HPPC and payment of differential for the deficit tariff paid, in which impugned Order is passed. The State Commission has framed following Issues, and deliberations therein are noted below:

Issue (a): Whether the settlement dated 29.09.2020 affects future tariff payable w.e.f. 01.04.2019.

44. After noting the contents of the settlement letters in previous round of litigation, State Commission held that settlement dated 29.09.2020 does not affect future tariff payable after 01.04.2019. Relevant paragraph is extracted hereunder: “The combined reading of the affidavit dated 18.09.2020 filed by the petitioner in the Commission read with its letters dated 17.08.2020 & 22.08.2020 addressed to the respondent along with the letter of the respondent (HPPC) to the petitioner dated 21.08.2020, finds considerable force in the arguments of the petitioner that the settlement was reached in respect of outstanding demand up to March, 2019 (ref. the calculation sheet of outstanding demand annexed with the letter dated 17.08.2020) that too on interim basis till the outcome of Civil Appeals (5962, 5869, 5843 & 7296 of 2018) preferred by the some other Solar Power Developers in Hon'ble Supreme Court. The same is evident from the reference to the words such as 'Reconciliation of pending payments', 'dispute of pending payments', 'the issue of claim of pending payments through negotiations', 'short payment by HPPC', 'compromise with HPPC on the issue of our pending claims of billing if HPPC releases our above outstanding amount' etc. Hon'ble APTEL., in its order dated 27.05.2019 (Appeal No. 150 of 2016) has upheld the decision of this Commission dated 20.01.2016 (HERC/PRO-24 of 2015), directing to allow the year to year tariff worked out corresponding to the levelized tariff of Rs. 6.44 per unit and the year to year tariff so worked out be paid to the Petitioner by Respondent (HPPC). Therefore, nothing was left to be settled in respect of the future payments. Because the settlement only addressed delayed payments for a specific historical period, it never discussed the applicable tariff rate for the remainder of the 25-year contract, since the order of Hon'ble APTEL in its order dated 27.05.2019, had already removed all ambiguities. The Petitioner did not surrender its ongoing contractual rights by settling past dues. The Contractual obligations cannot be diluted by any interim measures and the regulatory discipline requires strict adherence to adjudicated tariff. Any deviation may undermine the power sector's stability. Therefore, the bar contained under Order

XXIII Rule 1(4) of the CPC is not attracted, since the petitioner is not seeking to institute proceedings in respect of the claim that stood abandoned. Rather, the present petition pertains to claims arising for the period subsequent to the settlement. The Petitioner did not "abandon" its substantive right to the 25-year tariff. In view of the above discussion, the Commission answers this issue in negative i.e. the settlement dated 29.09.2020 does not affect the future tariff payable after 01.04.2019.” Issue (b). Whether the present petition is barred by principle of Res- Judicata in light of previous litigations

45. The State Commission observation is extracted below; “Therefore, the Commission's earlier observation in the Order dated 12.11.2024 (in PRO- 26 of 2024) that the issue had attained finality due to the settlement was limited to the settlement for past dues, not a re- determination of the tariff already settled at Rs. 6.44/kWh in the decisions of Hon'ble APTEL (order dated 27.05.2019 in Appeal No. 150 of 2016) along with the order of this Commission dated 20.01.2016 (HERC/PRO-24 of 2015). The underlying legal issue of the prospective tariff rate has not been definitively extinguished by any mutual contract amendment. Accordingly, the Commission holds that the present petition is not barred by Res Judicata and is maintainable under Section 86(1)(f) of the Electricity Act, 2003. In view of the above discussion, the Commission answers this issue in affirmative i.e. the present petition is not barred by the principles of Res Judicata, in light of the previous litigations.” Issue (c.) Whether the petition is barred by limitation

46. The State Commission observed that since the payment of energy is a continuous based on year to year, breach is continuous, and held that the petition is not barred by limitation. Relevant paragraph is extracted hereunder: “The Petitioner's grievance is that the Respondent is currently and continuously making payment of year to year tariff applicable

corresponding to the levelized tariff of Rs. 5.68/kWh determined by Hon'ble CERC instead of the legally mandated tariff corresponding to the levelized tariff of Rs. 6.44/kWh for ongoing power supply. Because of non-adherence to the PPA clarified by this Commission in its order dated 20.01.2016 (HERC/PRO-24 of 2015) confirmed by Hon'ble APTEL (order dated 27.05.2019 in Appeal No. 150 of 2016), which persists to date, the breach is continuous. Therefore, the petition seeking prospective compliance and payment of the tariff deficit for the un-settled period (post 01.04.2019) is squarely within the bounds of limitation. The objection of the Respondent is overruled. In View of above discussion, the commission answers this issue in negative i.e. the petition is not barred by limitation” Issue (d) Whether the Petitioner is entitled to a tariff of Rs 6.44/kwh as per PPA and the commission’s order dated 20.01.2016.

47. Referring to its order dated 20.01.2016, and APTEL’s Judgement dated 27.05.2019, State Commission held that Siwana is entitled for year to year tariff corresponding to levelised tariff of Rs 6.44/kwh w.e.f 01.04.2019 till the balance life of PPA and held as under: “In view of the above discussion, the Commission answers this issue in affirmative i.e. the petitioner is entitled to year to year tariff corresponding to levelized tariff of Rs. 6.44/kWh as per the PPA and the Commission's Order dated 20.01.2016 ?”

48. The final directions in the Impugned Order are extracted hereunder : “Accordingly, the Commission accepts the prayers of the Petitioner and passes the following directions:

1. The Respondent is directed to immediately implement the directions passed by this Commission on 20.01.2016 in Case No. HERC/PRO-24 of 2015, which was subsequently upheld by the Hon'ble APTEL vide Order dated 27.05.2019.

2. The Respondent shall pay the tariff to the Petitioner at the year-to- year rate corresponding to the levelized tariff of Rs. 6.44/kWh for the period from 01.04.2019 to the balance duration of the PPA.

3. The tariff paid till 31.03.2019 is covered under the settlement of arrears; hence shall not be re-visited.

4. The year to year rate corresponding to the levelized tariff of Rs. 6.44/kWh has been calculated, as per Annexure-A, based on the year to year tariff calculated by Hon'ble CERC in its calculation of levelized tariff of Rs. 5.68/kWh, by suitably changing the capital cost and keeping the other parameters unchanged. However, tariff for the period up to 31.03.2019 has been kept unchanged and the resultant impact has been equally spread over the years commencing from the current year i.e. FY 2026-27, to arrive at the levelized tariff of Rs. 6.44/kWh.

5. The Respondent is further directed to calculate the tariff deficit; being the difference between the year to year tariff corresponding to the levelized tariff of Rs. 6,44/kWh (as per Annexure A) and the year to year tariff corresponding to the levelized tariff of Rs. 5.68/kWh, for all energy injected by the Petitioner from 01.04.2019 onwards (i.e. the period subsequent to the final settlement of arrears) till 30.04.2026 and make the payment within thirty days from the date of this order. Further, in line with the principle of restitution, interest @ 9.15% p.a. i.e. the average rate of interest on working capital allowed to DISCOMs in the ARR order dated 25.03.2026, shall also be payable from the date the respective original monthly invoices were due till the date of payment of differential amount. The differential amount shall carry interest on a month-to-month basis, and the liability shall continue to accrue till full payment of both principal and carrying cost. Needless to add that any further delay in payment of differential tariff along with applicable interest thereon, beyond the allowed period of thirty days, will attract late payment surcharge @1.25% per month as per Article 5.6 of the duly executed PPA between the parties.”

49. The Appellant-HPPC has strongly contended that Petition No. 78 of 2025 is hit by principle of res-judicata, since the issue was already decided by the State Commission in its order dated 12.11.2024, passed in petition no 26 of 2024 and prayers made in these two petitions are identical and similar prayers have been made in earlier petitions also. It is further

contended that having reached the settlement as recorded in State Commission Order dated 29.09.2020, Siwana is barred from reopening the settled issues in terms of Order XXIII Rule 1 of Civil Procedure Code, 1908. It is also contended by Appellant that Siwana’s claim of Rs 6.44/kwh is barred by limitation not being fresh claim and State Commission vide its order dated 10.05.2019 had directed a payment of Rs 5.68 /Kwh and three year period has expired in May 2022.

50. Based on the submissions made by parties, following issues emerge for consideration: Issue A. Whether the tariff of Rs 6.44/kwh has been replaced by tariff of Rs 5.68 /kwh for Siwana’s Project.

51. It is not in dispute that Respondent No. 1–Siwana has, in earlier proceedings, consistently urged that the tariff of Rs 6.44/kWh made applicable to it ought to be substituted by the generic tariff determined by the State Commission, on the premise that the competitive bidding process stood vitiated and, therefore, no competitively discovered tariff survived. Reliance was placed on Clause 4.1 of the PPA to contend that the generic tariff should govern.

52. This Tribunal in its Judgement dated 09.03.2018 (Appeal No 278 & 307 of 2016), while finalizing the tariff of Rs 5.68/kwh for the four other developers noted that State Commission has already approved a tariff of Rs 6.44/kwh for the Siwana project in the PPA signed on 21.02.2014 and observed that since prices of solar panel are observing a downward trend, so generic tariff applicable for FY 2016-17 should be made applicable for

the projects of these four developers instead. The Judgement of this Tribunal, with regard to applicability of tariff of Rs 5.68/kwh was challenged by the four developers alone, Appellant HPPC chose not to challenge/ dispute the fact with regard to approval of tariff of Rs 6.44 / kwh for Siwana Project, as noted in this Judgement. This Tribunal in this judgement has only set aside the non-approval of PPA of other four developers with a direction to approve the PPA with applicable tariff of Rs 5.68/kWh for these developers and there is no direction with regard to PPA signed with Siwana and the Tariff made applicable for Siwana. Therefore, it can be inferred that tariff of Rs 6.44/kWh for Siwana remained undisturbed by this judgment. Despite this, HPPC started paying to Siwana at a tariff of Rs 5.68/kWh instead of Rs 6.44 /kWh from March 2019 onwards.

53. The State Commission in its order dated 10.05.2019, in the petition filed by Siwana, while acknowledging HPPC’s rights to settle energy bills at Rs 6.44 /kWh, and difficulty of HPPC in working out year on year tariff as directed by State Commission in its order dated 20.01.2016, simultaneously observed that tariff of Rs 6.44 /kwh discovered in competitive bidding has been “replaced” by Rs. 5.68 /kwh, and year to year tariff corresponding to Rs 5.68/kwh is available in CERC order dated 29.04.2016. State Commission in the order, as an interim arrangement, subject to judgement of Supreme Court in Civil Appeal Nos 5962,5869,5843 & 7296 of 2018 then pending before the Supreme Court for the further adjudication held that the year on year tariff corresponding to levelised tariff of Rs 5.68/ kWh shall be payable to Siwana, subject to outcome of civil appeals filed by four developers. Notably, this order contained no deliberations on the aspect that Tribunal Judgement dated 09.03.2018 takes note of the fact of approval of tariff of Rs 6.44/kwh for

Siwana and there is no direction with respect to tariff of Siwana Project. However, admittedly, the State Commission Order dated 10.05.2019 was not challenged by any party and as such Siwana’s Appeal against applicability of Rs 6.44/kwh, and not generic tariff order was pending adjudication in this Tribunal.

54. This Tribunal in its judgement dated 27.05.2019, in Appeal No 150 of 2016, while upholding the applicability of Rs 6.44/kwh for Siwana’s Project, instead of Generic Tariff order as sought by Siwana, took note of the issues pertaining to the competitive bidding process. Though, HPPC, disputed the applicability of Generic Tariff for Siwana’s Project, but had not pleaded for applicability of Rs 5.68 /kwh tariff, as made applicable for four developers in terms of the Order dated 09.03.2018 of this Tribunal instead of even Rs 6.44/kwh as per order dated 20.01.2016. This Tribunal upheld the Order dated 20.01.2016.

55. In view of the above, it is manifest that the tariff of Rs 6.44/kWh for Siwana’s project stood upheld by this Tribunal in its Judgment dated 27.05.2019, notwithstanding the applicability of a tariff of Rs 5.68/kWh for the four developers under a separate process. It cannot therefore be contended that the tariff of Rs 5.68/kWh stood substituted for Respondent No. 1–Siwana also. We have not been made aware if the Judgement dated 27.05.2019 of this Tribunal has been challenged.

56. However, whether Siwana can now claim enforcement of the tariff of Rs 6.44/kWh, is subject to the doctrine of res judicata, in light of the subsequent order of the State Commission dated 12.11.2024 and the

Settlement Order dated 29.09.2020, as contended by Appellant, which shall be examined in the succeeding paragraphs. Issue B: Whether Petition No. 78 of 2025 filed by Siwana is barred by res-judicata

57. As noted in preceding paragraphs, Siwana had earlier filed a petition No. 26 of 2024 before State Commission, setting out the entire history of litigation and praying for implementation of directions passed by State Commission order dated 20.01.2016 and payment of tariff at Rs. 6.44/kWh, together with the differential over Rs. 5.68/kWh. Siwana further submitted that following the Supreme Court's judgment dated 02.01.2024 upholding the settlement, the dues payable by HPPC up to September 2019 stood settled, and that the tariff question survived independently of that settlement. We take note that State Commission, by its Order dated 12.11.2024, held that "the sum and substance of all the petitions filed by the petitioner is the grant of tariff of Rs. 6.44/kWh", that the issue "stands resolved" by the orders dated 29.09.2020 and 14.09.2022 and the subsequent decisions of this Tribunal (21.08.2023) and the Supreme Court (02.01.2024), that it had "attained finality", and that "the principle of res judicata is squarely applicable" and dismissed the petition in limine, without going into the merits of the case.

58. Admittedly no appeal was filed against the said order of the State Commission by any party including Siwana.

59. The Respondent No 1-Siwana, subsequently filed Petition No. 78 of 2025, in which Impugned Order has been passed. Appellant has contended the applicability of the principle of res-judicata, as the prayers in the petition 78 of 2025, being identical to the prayers in petition No 26 of 2024, in which order dated 12.11.2024 has been passed dismissing the petition on account of res-judicata, which has not been challenged.

60. While dealing with this issue, the State Commission, in the Impugned Order has observed that commission’s earlier observation in the Order dated 12.11.2024 pertained to the settlement for past dues and not a re-determination of tariff already settled at Rs 6.44 /kWh and accordingly the present petition is not barred by principle of Res-Judicata. We find such an observation, legally unsustainable. In fact, as noted in proceedings paragraphs, the issue of applicability of Rs. 6.44/kwh for the Siwana Project had been deliberated in detail in the order dated 12.11.2024, including the principle of res-judicata as specifically noted in paragraph 13 & 14, extracted hereunder : “13. The Commission observes that the sum and substance of all the petitions filed by the petitioner is the grant of tariff of Rs. 6.44/kWh. The said issue stands resolved with the decision of this Commission rendered vide orders dated 29.09.2020 and 14.09.2022, decision of Hon'ble Appellate Tribunal for Electricity vide order dated 21.08.2023 and decision of Hon'ble Supreme Court vide order dated 02.01.2024. Thus, the issue has attained finality. Therefore, the principle of 'Res- judicata' is squarely applicable in the present case.

14. In terms of the above discussion, the present petition is dismissed in limine, without going into the merits of the case.”

61. It is apposite to extract Section 11 of the Code of Civil Procedure 1908 along with applicable explanations, as under:

"11. Res judicata. -No Court shall try any suit or issue in which the matter directly and substantially in issue has been directly and substantially in issue in a former suit between the same parties, or between parties under whom they or any of them claim, litigating under the same title, in a Court competent to try such subsequent suit or the suit in which such issue has been subsequently raised, and has been heard and finally decided by such Court …. Explanation III. The matter above referred to must in the former suit have been alleged by one party and either denied or admitted, expressly or impliedly, by the other. Explanation IV. Any matter which might and ought to have been made ground of defence or attack in such former suit shall be deemed to have been a matter directly and substantially in issue in such suit."

62. The Section 11 of the Code of Civil Procedure, 1908, embodies the doctrine of res judicata, a principle of high public policy which mandates that there must be an end to litigation. Section 11 CPC (1908) mandates that once a matter has been directly and substantially adjudicated between the same parties by a competent court, neither the same issue nor any issue that ought to have been raised can be re-agitated in subsequent proceedings. The doctrine rests upon the twin maxims interest reipublicae ut sit finis litium (it is in the interest of the State that there be an end to litigation) and nemo debet bis vexari pro una et eadem causa (no person should be vexed twice for the same cause). The provision, reinforced by its explanations, extends not only to matters actually decided but also to those which might and ought to have been raised in the earlier proceedings, thereby incorporating the principle of constructive res judicata. The Supreme Court has consistently held that Section 11 is exhaustive of the doctrine in civil proceedings and operates as a bar even

where the earlier decision may be erroneous, the remedy lying in appeal or review rather than fresh litigation. Thus, the provision secures finality of adjudication, prevents multiplicity of suits, and upholds the sanctity and authority of judicial determinations.

63. It is apposite to extract the prayers sought in Petition No.26 of 2024 in which order dated 12.11.2024 is passed and Petition No. 78 of 2025, in which order dated 14.05.2026, impugned in the present Appeal is passed, as under: Petition No. 26 of 2024 Petition No. 78 of 2025 A. Implement the directions passed by this Hon'ble Commission on 20.01.2016 in Case No. HERC/PRO-24 of 2015 and direct the Respondent to pay tariff to the Petitioner at the rate of Rs.6.44 per unit in accordance with the Power Purchase Agreement dated 21.02.2014 executed between the parties; B. Direct the Respondent to also pay to Petitioner the tariff deficit between Rs. 6.44 and Rs. 5.68 per unit payable till the final adjudication of the present petition, within a time bound manner, A. Direct the Respondent to adhere by the terms and conditions of the Power Purchase Agreement dated 21.02.2014 in full capacity and pay tariff to the Petitioner at the rate of Rs.6.44 per unit. B. Implement the directions passed by this Hon'ble Commission on 20.01.2016 in Case No. HERC/PRO-24 of 2015 and direct the Respondent to in accordance with the Power Purchase Agreement dated 21.02.2014 executed between the parties;

C. Pass any other order as this Hon'ble Commission may deem fit and necessary in the facts and circumstances of the present case. C. Direct the Respondent to also pay to Petitioner the tariff deficit between Rs. 6.44 and Rs. 5.68 per unit payable till the final adjudication of the present petition, within a time bound manner; D. Pass any other order as this Hon'ble Commission may deem fit and necessary in the facts and circumstances of the present case.

64. It is evident from above that identical prayers have been made by the Petitioner in these two appeals. The conditions for res judicata laid down in Syed Mohd. Salie Labbai v. Mohd. Hanifa, (1976) 4 SCC 780, are squarely met in the present case: the parties in Petition No. 26 of 2024 and Petition No. 78 of 2025 are the same, the subject-matter is identical i.e, Siwana's entitlement to Rs. 6.44/kWh as against Rs. 5.68/kWh. As the order dated 12.11.2024 passed by State Commission in Petition No. 26 of 2024 was never appealed, it has attained finality, and Satyadhyan Ghosal v. Deorajin Debi, 1960 SCC OnLine SC 15, bars either party from canvassing the same matter afresh in a subsequent proceeding between them as settled in Sulochana Amma v. Narayanan Nair, (1994) 2 SCC

14. Consistent with Swamy Atmananda v. Sri Ramakrishna Tapovanam, (2005) 10 SCC 51, Bhanu Kumar Jain v. Archana Kumar, (2005) 1 SCC 787 where it is held that no litigant should face the same litigation twice and M. Nagabhushana v. State of Karnataka, (2011) 3

SCC 408, that a final determination must set the controversy at rest, any error being correctable only in appeal or review, not fresh litigation. The "past dues" versus "prospective tariff" distinction drawn in the Impugned Order does not survive scrutiny, since the finality attaching to the Order dated 12.11.2024 went to Siwana's entitlement of Rs 5.68 /kWh and not to Rs. 6.44/kWh itself, not merely to a tranche of arrears.

65. Respondent No 1-Siwana referring to this Tribunal judgement dated 27.05.2019, which fixed the tariff of Rs 6.44/kwh for its project, placed reliance upon “Damodar Valley Corporation versus West Bengal State Electricity Distribution Company Limited and Ors.”; ,“Union of India v. S.P. Sharma”;, (2014) 6 SCC 351, “Delhi Electricity Regulatory Commission versus Tata Power Delhi Distribution Limited” (Civil Appeal 6388 of 2025) to contend that once a judicial determination attains finality, the same cannot be indirectly nullified through subsequent administrative action, selective interpretation, or continued non- compliance.

66. As already noted above, this Tribunal vide its order dated 27.05.2019 had affirmed a tariff of Rs 6.44/kWh for the project of Siwana, which was not challenged by HPPC, notwithstanding its awareness that there has been alteration of tariff so discovered through competitive bidding process for other four developers. However, in subsequent proceedings culminating in the State Commission Order dated 12.11.2024, the State Commission, relying upon orders of this Tribunal, Supreme Court and its own pronouncements, held that the issue stood settled and that the applicable tariff for Siwana is Rs 5.68/kWh. That order, not having been assailed, has attained finality between the parties. In such

circumstances, the principle of res judicata gets applied. Once the issue of applicable tariff has been adjudicated upon and has attained finality, the same cannot be re-agitated in subsequent litigation under the guise of fresh prayers or renewed submissions. While this Tribunal acknowledges the earlier determination of tariff at Rs 6.44/kWh for Siwana Project, the subsequent unchallenged order of the State Commission dated 12.11.2024 fixing the tariff at Rs 5.68/kWh is to be treated as conclusive and binding. The attempt to re-litigate the same issue is barred by res judicata. Its effect, properly understood, is not that it "fixed" or affirmatively re-determined the tariff at Rs. 5.68/kWh but is that it conclusively and finally determined, between these parties. That determination, unchallenged, has itself attained finality and therefore, parties are estopped from raising the matter afresh in the present proceedings. Therefore, entitlement of tariff of Rs. 6.44/kWh for Siwana in Impugned Order cannot be sustained.

67. In view of the foregoing discussion, we hold that the issue of applicable tariff for the project of Respondent No. 1–Siwana stands concluded by the order of the State Commission dated 12.11.2024, which affirmed the tariff at Rs 5.68/kWh. That order, not having been challenged, has attained finality inter se between the parties and cannot be pressed afresh in Petition No. 78 of 2025 under the guise of a fresh prayer or renewed submissions. The observation in the Impugned Order that the very same issue is not barred by principle of res-judicata is erroneous and legally non sustainable and need interference.

68. In view of above deliberation, we do not feel it necessary to deliberate other issues of limitation, settlement order etc.

69. Accordingly, we hold that issue of applicable tariff for the project of Respondent No 1- Siwana stood finally decided by the order of the State Commission dated 12.11.2024, which affirmed the tariff at Rs 5.68/kWh and hence the issue of applicability of tariff @Rs 6.44/kwh raised by the Respondent No.1-Sinwana again in the subsequent Petition No.78 of 2025 was barred by the principle of res-judicata enshrined under Section 11 of the Code of Civil Procedure, and Commission has fallen into an error in holding that Petition No.78 of 2025 was not barred by the principle of res- judicata in the Impugned order. Accordingly, the Impugned Order cannot be sustained in law and therefore it is set aside. The appeal is allowed in above terms and is disposed of along with pending IAs if any. PRONOUNCED IN THE OPEN COURT ON THIS 18th DAY OF SEPTEMBER, 2026. (Virender Bhat) Judicial Member (Seema Gupta) Officiating Chairperson REPORTABLE / NON-REPORTABLE _________________________________________________ pr/dk/ak/ag