On Wednesday, the Oklahoma Supreme Court will hear arguments on OG&E's plan to have customers pay for the emergency costs from last February's historic freeze.
The challenge is specifically related to OG&E's attempts to recover the nearly $800 million spent during last year's winter storm.
The extreme cold forced utility companies to pay skyrocketing rates for natural gas.
A state law passed last year allows energy companies to have customers pay extra to cover the costs over the next two and a half decades.
But several OG&E customers said it's unconstitutional.
Former Oklahoma Rep. Porter Davis argued the measure changes the state constitution without a vote of the people.
Another challenger, James Pickel, said it violates his contract with OG&E and that customers didn't agree to the extra costs and there's no guarantee the plan will work.
Meanwhile, the Oklahoma Corporation Commission just approved a plan to raise costs for Oklahoma Natural Gas customers.
ONG is using the same bond process to recoup 1.3 billion over the next 25 years.