Alliant Energy's Iowa energy company received approval from state regulators to increase its wind expansion program. By 2020, the company now plans to add 1,000 megawatts of wind energy generating capacity in Iowa, enough to power 430,000 homes.

The company plans to have invested $1.8 billion in the additional generating capacity by the end of 2020.

This spring, crews began construction on the first of several wind farms, starting with Upland Prairie Wind Farm, located in Clay and Dickinson counties in northwest Iowa. This project uses 121 GE-manufactured turbines with a nameplate capacity of 2.3 and 2.5 MW.

The capacity additions will include GE 2.3 and 2.5 MW turbines. Credit: GELater in 2018, work is expected to start at English Farms Wind Farm, located in Poweshiek County in central Iowa. This project will use 69 GE-supplied turbines, also rated at 2.3 and 2.5 MW.

Through this expansion, combined with existing wind farms and market purchases, the company expects wind to be approximately one-third of its Iowa total generating capacity by the end of 2020.

Alliant Energy's Iowa energy company, Interstate Power and Light, filed an application for advance ratemaking principles on Aug. 3, 2017.

Under terms set out by the Iowa Utilities Board a construction cost cap $1,780/kilowatt will be in place, including allowance for funds used during construction (AFUDC) and transmission costs. Regulators allowed an 11 percent return on equity, with the exception of transmission facilities classified as intangible assets.

The board also allowed a depreciable life of 40 years and ruled that Alliant Energy's Iowa customers will receive the full value of any environmental attributes, beyond those needed to meet regulatory requirements.

Interstate Power and Light Co. is based in Cedar Rapids, Iowa, and provides electric service to 490,000 retail customers and natural gas service to 220,000 retail customers.

According to the state's utility regulator, Iowa's installed generating capacity rose from 921 MW in 2006 to 6,314 MW in 2015. Wind's share of electric generation rose over the same period from 5.1 percent to 31.5 percent.

The American Wind Energy Association says that Iowa currently has 7,308 MW of installed wind generating capacity, the third highest amount in the country.

The state is also home to 11 wind-related manufacturing facilities. In January, Siemens Gamesa Renewable Energy said it planned to cut more than 200 jobs at its Fort Madison, Iowa, wind turbine blade plant. The layoffs will leave around 330 workers at the plant.

“Business volume at this location through the 2018 fiscal year does not support the existing workforce level,” Siemens Gamesa representatives said in a statement, according to news reports.