Alliant Energy customers in Albert Lea will see a new rate, effective today and will receive a refund from the recent rate case between late March and May, according to an Alliant Energy spokesman on Thursday.

Scott Drzycimski, customer communications manager for Alliant Energy, said the company filed compliance filings — which included what the new rates will be for each customer class — with the Minnesota Public Utilities Commission. The new rates are about 6 to 7 percent lower than the interim rate customers had been paying.

Refunds are being issued because the Public Utilities Commission in June approved a revenue increase for Alliant Energy’s subsidiary Interstate Power & Light that was less than what customers have been paying under interim rates since July 2010.

The commission ultimately approved a revenue increase of about $7.7 million out of an original $14 million annual request by the company.

A brochure will be included with customers’ next bill. The brochure shows that an average residential customer was paying about $70 per month before the rate increase, then about $84 from July 6, 2010, to Feb. 17. The new average monthly rate will be around $78.

Drzycimski said customers’ bills going back to July 2010 will be recalculated with the new rate that has been approved. The refund will be the overage customers had been paying since the interim rates were initiated, plus 3.25 percent interest. The refund will be different based on customer class, usage and size of their home or building.

Drzycimski said because of how refunds are calculated in Minnesota, coming up with an average amount customers will receive is a little difficult. He said the actual amount each customer will receive varies; however, it appears most residential customers will see between a $35 and $40 credit on one bill sometime between late March and May.

The refund is based on a customer-by customer calculation of the interim each customer paid. The MPUC order approved a final increase that’s nearly 84 percent of what customers were already paying under the interim rate increase. Based on that, the remaining 16 percent will be refunded to customers plus interest calculated at 3.25 percent.

Alliant Energy filed the rate case in mid-2010 to add to base rates the added costs of 5 years of infrastructure additions and improvements, a new wind farm, emissions control equipment at power plants and, to a lesser extent, small increases in the cost of doing business, according to Drzycimski.

Drzycimski did note that lighting costs, applicable to the city of Albert Lea for some of its streetlights, were brought back down to the rate it was at before the rate increase.