JUDGMENT :

AUGUSTINE GEORGE MASIH, J.

1. This Civil Appeal assails the Judgment dated 17.03.2023 in Appeal No. 30 of 2023 (“Impugned Judgment”) by the Appellate Tribunal for Electricity at New Delhi (“APTEL”) which reversed the findings returned vide Order dated 27.12.2022, by Himachal Pradesh Electricity Regulatory Commission at Shimla (State Commission) in Petition No. 35 of 2022, holding M/s Brua Hydrowatt Pvt. Ltd., Respondent No. 01 herein (“BHP Ltd”) liable to bear the entire cost for Bay at the 66kV Switching Station at Urni (“Bay”) which was constructed by the HP Power Transmission Corporation Limited, Appellant herein (“HPPTC Ltd”) as per the Connection Agreement (Revised) dated 02.07.2021 “(CA dated 02.07.2021”).

2. The details of the parties before us are that the HPPTC Ltd. is a transmission licensee responsible for executing transmission networks, including transmission lines and sub-stations of 66kV and above in the State of Himachal Pradesh. The BHP Ltd. formerly known as M/s Contransys Pvt. Ltd. is a company incorporated under the Companies Act, 1956, and classified as a generating company under Section 02 (28) of the ELECTRICITY ACT , 2003. Respondent No. 02 and Respondent No. 03, being M/s Darjeeling Power Pvt. Ltd. and M/s Roura Non-Conventional Energy Pvt. Ltd. respectively, are the other generating companies engaged in hydroelectric projects within the State of Himachal Pradesh. Respondent No. 04 and 05 are proforma respondents, being the State Commission and State of Himachal Pradesh respectively.

3. The facts leading to the case are that Government of Himachal Pradesh entered into an Implementation Agreement with the HPPTC Ltd. on 25.07.2006 to establish the Brua Hydro Electric Project (“BHEP”) initially with a capacity of 05 MW. The interconnection was originally planned at a 33kV single circuit transmission line at Karcham in Kinnaur district of Himachal Pradesh. However, the Power Purchase Agreement dated 06.04.2009 was revised through a Supplementary Power Purchase Agreement on 09.07.2018 to increase the capacity to 09 MW at a fixed tariff of INR 2.93 per unit. The connection at Karcham was approved on 03.12.2010 by the Himachal Pradesh State Electricity Board Ltd. (HPSEBL), but stood modified to be connected at Urni instead of Karcham, allowing for the Bay in joint mode for the three generating companies i.e. BHEP, Shaung and Roura-II Hydro Power Project.

4. To this effect, an application for connectivity had been submitted by the BHP Ltd. on 04.07.2012 and stood approved by the HPPTC Ltd. on 18.03.2013 and 23.04.2013 leading to the Connection Agreement dated 04.06.2014, designating Urni as the connection point. Admittedly, the HPPTC Ltd. informed the BHP Ltd. on 04.12.2015 that Bay would only be operational after completion of the Urni-Wangtoo 66kV line and the Wangtoo sub-station. In the interregnum, it allowed BHP Ltd. to utilize the 220kV Kahshang Bhaba line circuit at 66kV. Further, in pursuance of direction of the HPSEBL, the HPPTC Ltd. completed a 66kV feeder Bay at Nathpa sub-station for interim power evacuation, leading to signing of Interim Power Transmission Agreement dated 23.01.2016, requiring the BHP Ltd. to pay INR 0.14 per unit to the HPPTC Ltd. for providing interim arrangements.

5. All three generating companies i.e. BHP Ltd. Respondent No. 02 and Respondent No. 03 entered into an Internal Tripartite Agreement dated 27.12.2019 (ITA dated 27.12.2019) to allow for proportionate sharing of transmission charges, including the cost of Bay installed by the HPPTC Ltd. at Urni. As per the agreement, while the BHP Ltd. would handle claims for deemed generation a