JUDGMENT

H.L. Gokhale, J.

1. All these five appeals arise out of a common order dated 20.4.2007 passed by Appellate Tribunal for Electricity (`Appellate Tribunal' for short) while deciding the First Appeals to the Appellate Tribunal under Section 111 of the Electricity Act, 2003 against the orders of the Central Electricity Regulatory Commission (`The Central Commission' for short), dated 1.4.2005, 7.4.2005 and 2.6.2006 passed under Section 62 of the Electricity Act, 2003. While admitting these appeals, this Court has stayed the operation of the impugned order until further orders.

(a) First of these three Civil Appeals are filed by M/s NTPC Ltd. The Madhya Pradesh State Electricity Board (`MPSEB' for short) and others are respondents to this Civil Appeal No.2451/2007. The Punjab State Electricity Board (`PSEB' for short), Delhi Vidyut Board and others are the respondents to the other two appeals being Civil Appeal No.2452/2007 and Civil Appeal No.2493/2007.

(b) Civil Appeals Nos. 3972 and 4231 of 2007 are filed by the PSEB and Delhi Vidyut Board. The Central Commission, M/s NTPC Ltd. and others are the respondents to these two appeals.

2. M/s NTPC Ltd. is a power `generating company' within the definition of the concept under Section 2 (28) of the Electricity Act, 2003. The Electricity Boards concerned, receive the power generated from the thermal power plants of NTPC situated at Kawas, Gandhar and Rihand. The Central Commission had determined the tariff payable by the Electricity Boards to NTPC by the above referred orders dated 1.4.2005, 7.4.2005 and 2.6.2006.

(i) The orders dated 1.4.2005 and 7.4.2005 were on the Petitions No.33 of 2001 and 31 of 2001 respectively filed by NTPC for determining the tariff with respect to the power supplied by it during the period 1.4.2001 to 31.3.2004 to MPSEB and others from Gandhar and Kawas power stations.

(ii) The order dated 2.6.2006 was on Petition No.38 of 2001 by NTPC for the determination of tariff with respect to power supplied during the same period from the Rihand power station to PSEB, Delhi Vidyut Board and others.

3. The Central Commission while determining the tariff, had determined the final tariff at a rate lesser than the pre-existing tariff, as a result of which NTPC was found to have collected excess amounts during this intervening period, and the Electricity Boards became entitled to get the refund/adjustment of these differential amounts. Thus, the amount overcharged in respect of Gandhar power station is to the tune of Rs.460.52 crores and the one in respect of Kawas power station is Rs.254.47 crores. The Central Commission had however disallowed the claim of the Electricity Boards for payment of interest on the differential amounts between (i) the tariff finally determined by the Central Commission and (ii) the pre-existing tariff continued by the Central Commission until the final determination of the tariff. There is no dispute that thereafter NTPC has duly and immediately adjusted the excess amounts in favour of the purchaser Electricity Boards in their subsequent bills.

4. The MPSEB, PSEB and Delhi Vidyut Board, therefore, invoked Section 111 of the Electricity Act, 2003 and filed appeals against the above three orders of the Central Commission before the Appellate Tribunal which were numbered as Appeal Nos.64, 212 and 237 of 2006. The Appellate Tribunal rejected the claim of the Electricity Boards for interest as being payable under Section 62(6) of the Electricity Act, 2003. It however, held by its impugned common order dated 20.4.2007, that NTPC was liable to pay interest on the differential amounts on the grounds of justice, equity and fair-play. The NTPC has therefore, filed three Civil Appeals being Civil Appeal Nos. 2451/2007, 2452/2007 and 2493/2007 to challenge this order. As against that, PSEB and Delhi Vidyut Board have filed Civil Appeal Nos. 3972/2007 and 4231/2007 to challenge the same order of the Appellate Tribunal to the extent it rejected their cl