How much of a rate increase the utility wants won't be known until the petition is filed with the Indiana Utility Regulatory Commission in July.
The rate case is a formal process all regulated utilities must go through in order to change their base rates, according to Nike Meyer, communications manager for Northern Indiana Public Service Co.
Meyer said it is early in the process and the company will be working through analysis to determine what impact there will be on customers. "We don't have a lot of details at this point," Meyer said.
Beth Roads, commission counsel for the Indiana Utility Regulatory Commission, said the rate case is a lengthy legal process that takes an in-depth look at the utility, its services and its electric facilities to determine if the base rate should be adjusted.
"Under standard utility law … utility companies are allowed to make a certain rate of return on their rate base," Roads said.
Improvements to infrastructure and the addition of plants would be reasons a company could file a rate case to have its base rate adjusted, she said.
The entire process, which will include public hearings and a chance for consumers to respond to both the IURC and OUCC, will take one to two years.
Roads said while the utility has not had a rate case in 20 years, that does not mean its rates haven't been adjusted from time to time. "Their rates have been looked at in other ways in that 20 years," Roads said. The most common way would be fuel adjustment cases.
NIPSCO is a NiSource subsidiary with 456,000 customers in northern Indiana.
NiSource CEO Robert Skaggs revealed plans for the rate case during a conference call with Wall Street analysts Friday to talk about the company's first-quarter earnings.
Profits in the first quarter were $99.3 million, or 36 cents per share -- down from $216.7 million, or 79 cents per share, in the first quarter of 2007.