According to sources, the four states received approvals from their respective Cabinets to challenge the Central Electricity Regulatory Commission's decision before the Appellate Tribunal for Electricity.
The CERC last month allowed Tata Power and Adani Power to charge higher tariff and recover arrears of over R1,150 crore. The decision was aimed at mitigating losses due to an increase in the price of Indonesian coal used by the companies at their plants in Mundra, Gujarat.
Tata Power runs a 4,000 MW ultra mega power project at Mundra while Adani Power operates a 4,620 MW plant. Tata Power won the bid for Mundra in 2007 by offering a levelised tariff of R2.26 per unit for 25 years.
The CERC said the higher tariff would be imposed with retrospective effect from April 1, 2013, entitling Tata Power to recover R329.45 crore and Adani Power almost R830 crore.
Tata Power's Mundra plant sells power to customers in the four states and Rajasthan while Gujarat and Haryana also purchase electricity from Adani.