CEDAR RAPIDS — Plans for Alliant Energy’s latest wind project would add another 170-megawatt wind farm to the state’s growing population of turbines.

On the back of Alliant’s 2016 pledge to spend $1 billion on 500 megawatts of wind power, a contract between Alliant and the turbine contractor for the Poweshiek County project received final approval Tuesday and the wind farm will be completed in 2020.

“For a lot of reasons it’s a good project that is going to be able to compliment a lot of the other projects we have ongoing,” said Ben Lipari, director of resource development with Alliant Energy.

He added the utility is “active in evaluating additional projects.”

Combined with similar projects by the state’s other main utility company, MidAmerican Energy, Alliant’s latest wind power contract caps off a year that saw hundreds of megawatts of wind energy — both underway and proposed — added to Iowa’s growing renewable energy portfolio.

Alliant’s investment in wind — including both announced and potential projects — will mark a more than threefold increase from the utility’s 300 megawatts of wind power earlier this year to about one gigawatt by 2020, Lipari said.

Meanwhile, MidAmerican this year began construction at the first two sites of its $3.6 billion, 2,000-megawatt Wind XI project. The 168-megawatt Prairie and 170-megawatt Beaver Creek projects, located in Mahaska County and Boone and Greene counties, respectively, are expected to go online yet this year.

A third site for the Wind XI project, a North English wind farm in Poweshiek County, will be completed next year and add another 340 MW to the grid.

Wind XI is expected to be finished by the close of 2019.

In addition, MidAmerican has plans to upgrade 706 of the utility’s older turbines with newer, more efficient components to increase their energy production.

By the end of 2020, MidAmerican expects to produce up to 95 percent of the annual power consumption of its customers with wind. Utility officials eventually hope to reach 100 percent, officials said in an email.

Combined with Alliant, the two utilities expect to bring the state’s wind power total up to nearly 10,000 MW by 2020, compared to less than 1,000 MW in 2006.

Iowa currently generates more than one-third of its electricity from wind power. In 2010, wind made up less than half that — about 16 percent of the state’s power, said Nathaniel Baer, program director with the Iowa Environmental Council.

“I think we’ve seen good progress in wind energy every year for the last 10 or so years,” Baer said.

Recent investments in wind power largely have been driven by industry concerns following the 2015 decision by lawmakers to phase out the Federal Production Tax Credit by 2019. The PTC is an inflation-adjusted, per-kilowatt-hour tax credit that provides credits for energy generated by qualified renewable sources such as wind.

Within a year after the PTC phaseout was announced, Alliant and MidAmerican had announced nearly $5 billion — $3.6 billion by MidAmerican and $1 billion by Alliant — in combined wind projects as both utilities try to take advantage of the credit before it expires.

“Many in the industry believe that, what we call the 100 percent PTC ... may never be as good as it will ever be again,” Lipari said. “It is really a critical element to why you have seen the volume spike.”

Proponents of renewables say the addition of wind and solar help diversify the power grid, which allows for lower energy rates as well as provide environmental benefits.

In addition, Iowa landowners in 2015 received more than $17 million in lease payments from wind farms. That number is expected to double in the coming years, according to the Iowa Environmental Council.

Counties with wind farms — including Pottawattamie, Buena Vista and Carroll — also have seen annual property tax revenue increase by more than $1 million a piece, according to the council.

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