JUDGMENT

SURINDER SINGH NIJJAR, J. –

1. This statutory appeal under Section 125 of the Electricity Act, 2003 (hereinafter referred to as the “Act”) is directed against the final judgment and order dated 22nd February, 2013 passed by the Appellate Tribunal for Electricity (hereinafter referred to as “APTEL” or “Appellate Tribunal”), at New Delhi in Appeal No. 176 of 2011, whereby it has dismissed the appeal preferred by the appellant against the final judgment and order dated 17th June, 2011 of Tamil Nadu Electricity Regulatory Commission (hereinafter referred to as the “State Commission”) in D.R.P. No. 12 of 2009. The facts have been noticed in detail both by the State Commission and the APTEL, therefore, we shall make a reference only to the very essential facts necessary for deciding this appeal.

2. The respondent, a generating company, has entered into a Power Purchase Agreement (PPA) with the appellant on 3rd January, 1997 for the supply of the entire Electricity to be generated by the respondent for a period of 30 years. The respondent commenced commercial operations on 26th April, 2001. Under the PPA, the respondent has to submit an annual invoice indicating the amounts owed un