If this week’s ruling stands, it will save U.S. Steel a significant amount on its bill, but the company has declined to specify how much those savings might total.

U.S. Steel has disputed NIPSCO’s elaborate mathematical calculations and use of terms such as “energy rates” and “usage rates” in determining the steelmaker’s electric bill.

U.S. Steel attorney Jack Wickes said his client is pleased the court upheld a 1999 ruling by the state Utility Regulatory Commission and lower court decisions favoring U.S. Steel. NIPSCO spokesman Nick Meyer said the utility had not decided if it will appeal the ruling.