Interstate Power and Light Company, a subsidiary of Alliant Energy, has announced that its proposed generation expansion plan will lower the company's system-wide emissions levels in 2013, the scheduled operation date of the proposed fourth unit in the Sutherland generating station.

Interstate Power and Light’s (IPL) generation plan includes construction of up to 200MW of wind generation and a 350MW ownership share of the proposed Sutherland generating station Unit 4 (SGS4).

In its rebuttal testimony filed with the Iowa Utilities Board regarding IPL’s request for certification of SGS4, the utility presented evidence that a scenario in which no additions are made to its generating fleet is more costly to customers and creates higher emissions levels in 2013 when compared to its proposed generation expansion plan.

The utility claims that the addition of SGS4 and up to 200MW of wind generation along with the corresponding displacement of generation from less efficient facilities and reduction of purchased power is equivalent to removing nearly 443,000 metric tons of carbon dioxide from the environment.

The 630MW SGS4 unit uses hybrid technology, which includes output from the utilization of coal and agriculturally-based products, and an additional 19MW equivalent of steam cogeneration available for use by nearby industries.