Interstate Power & Light Co. is seeking approval from the Iowa Utilities Board to increase its annual retail electric revenues by $176 million, or 11.6%, premised upon a return on common equity of 10.3%.
The Alliant Energy Corp. subsidiary proposed to implement the increase in two phases. In the first phase, the utility will implement an interim rate increase of $102 million, effective April 13. The remaining $74 million increase will be be implemented upon final approval, according to an April 3 release.
The increase will help the company recover investments it made to upgrade its power system and add the Marshalltown Generating Station and Franklin County Wind Farm to its generating fleet.
If approved, a typical residential customer with a monthly electric bill of $114 will see an increase of approximately $14 per month, which will be offset by tax credits and transmission refunds, the utility said.
The request is based on a retail electric rate base of $4.1 billion, including deferred tax assets for production tax credits and post-test year additions through the third quarter of 2017, and common equity component of regulatory capital structure of 49%, among other things.
IPL asked the regulator to issue a final decision in the fourth quarter of 2017. (Docket No. RPU-2017-0001).