Alliant Energy Corp. announced today it has accepted an Iowa Utilities Board proposed decision and order related to its request to construct a new electrical generating plant in Marshalltown. The utilities board on Nov. 8 issued a proposed decision that included a cost cap of $920 million for the 650-megawatt Marshalltown Generating Station, which will be operated by Alliant subsidiary Interstate Power & Light Co. The board's decision provides for an 11 percent rate of return on equity for the company on the natural gas-powered plant. On Monday, Alliant received a proposed decision and order approving the natural gas pipeline to serve the facility, the company said in a release. Pending all regulatory approvals, the utility expects to start construction in 2014 and begin plant operations in 2017.