Alliant Energy’s request made last year to increase customer energy rates was approved Friday in a settlement agreement by the Iowa Utilities Board.
Interstate Power and Light Company — Alliant Energy’s parent company — last April applied for an approximately $175.5 million, or 11.6 percent, increase in electric rates.
That request was amended to about $168 million, and the final increase was adjusted downward more to $130 million, or about 7.8 percent, in the settlement.
Officials with Alliant said the exact updates to customer rates will be known in a few weeks.
In the settlement document, fixed customer charges for residential rates would increase from $10.50 to $11.50. General service rates would go from $17.80 to $19, the document said.
Alliant began phasing in temporary rate increases last spring.
Company officials have said the rate increase, which was estimated last year at between $12 to $14 per month, represents about $2.5 billion in capital investments in the electrical system — into such efforts as power grid upgrades and the new Marshalltown natural gas generating station — since the last increase about six years ago.
Alliant’s average customer bill last year was about $113 monthly. The utility serves about 500,000 customers.