State discoms of Gujarat, Haryana, Maharashtra, Punjab and Rajasthan are like to move the Supreme Court in next few days against the APTEL's interim order of July 21, government and industry sources said.
Prior to APTEL, the CERC had allowed Tata Power and Adani Power to charge compensatory tariff from procurers with whom they have signed PPAs.
The Appellate Tribunal for Electricity (APTEL) had on July 21 allowed Tata Power and Adani Power to recover power dues from March 2013 on account of rise in imported fuel cost.
However, the Tribunal said the companies will not recover any pre-March 2013 arrears.
The ruling would provide a cushion to the companies against escalation in cost of imported coal for the plant.
According to an estimate, pre-March, 2013 dues for Tata Power's 4,000 megawatt Mundra Plant in Gujarat stand at Rs 330 crore, while the same for Adani's 1,980-MW Mundra project in Gujarat is Rs 830 crore.
After March 2013, Tata Mundra UMPP will be awarded compensatory tariff at 52 paise per unit, which will fetch the company Rs 25,000 crore over the remaining life of the plant.
In the case of Adani's Mundra project, the power company will get compensatory tariff at 41 paise unit, a move that will give it Rs 18,500 crore over the remaining life of the project.
These firms had sought relief on account of adverse impact of the unforeseen, uncontrollable and unprecedented escalation in the imported coal price.
In April last year, Central Electricity Regulatory Commission (CERC) said in its orders that Adani Power should be granted compensation packages for their projects.
Besides, the regulator, in a separate order, allowed Tata Power to increase tariff from its 4,000-MW ultra mega power project at Mundra.
The Commission had asked the states which buy electricity from Tata Power's Mundra plant to form an expert panel to decide on compensating the firm for higher cost of coal imports from Indonesia.
Also, Reliance Power has filed petitions with CERC for compensatory tariff on various accounts for its three UMPPs -- Sasan, Tilayia and Krishnapatnam.