Alliant Energy begins power plant construction

Alliant Energy's Iowa utility has begun construction of a $700 million, 650-megawatt electric generating plant in Marshalltown after securing all the necessary regulatory approvals and permits.

The Cedar Rapids utility said it has issued a 'full notice to proceed” and selected KBR Inc. of Houston, Texas, as the engineering, procurement and construction contractor for the combined-cycle, natural gas-fueled plant.

The Marshalltown Generating Station is expected to power more than 500,000 homes when it begins commercial operation in the second quarter of 2017.

The Iowa Utilities Board conditionally approved the electric generation certificate for the Marshalltown Generating Station in November. The order established an overall cost cap of $920 million for the plant's construction as well as necessary transmission and related costs.

The order also established ratemaking principles for the proposed project and cost recovery factors to be included in a future rate case. The principles and factors include an 11 percent rate of return on equity and a depreciation lifetime of 35 years for the project during which the company can recover its investment.

John Larsen, Alliant Energy's senior vice president of generation, said the Marshalltown plant will be a key component of the utility's long-term energy resource plan that balances energy supply with reducing emissions.

The plan, announced in August 2012, also includes investments to reduce emissions and increase the efficiency of Alliant Energy's Iowa utility's existing coal-fired generating plants as well as retiring older and less efficient coal-fired generating stations.

Alliant Energy's Iowa utility also signed a new long-term nuclear purchase power agreement with NextEra Energy and the minority owners of the Duane Arnold Energy Center near Palo to buy 431 megawatts of capacity and energy.