It is no April Fool.

Conversely, it is as real as flipping a switch in a darkened room and seeing it erupt in light.

The mammoth natural gas-fired Marshalltown Generating Station will begin supplying electricity for Alliant customers this Saturday, April 1.

That was the news Thursday from Joel Schmidt, vice president for regulatory affairs for Alliant Energy in Cedar Rapids.

The largest economic development project in Marshalltown’s history, and one of the biggest ever in Central Iowa will begin serving customers as planned.

Over a two and one-half years the economic impact has been chart-busting, with $47.3 million spent in the Marshalltown area by contractors and workers effective Feb. 13, according to Alliant officials.

Kenn Vinson of Alliant reported to the city council last month volumes of materials used in construction:

• 2,700 tons of scaffolding

• 4,500 tons of steel

• 29,750 cubic yards of concrete

• 150,500 feet of piping installed

• 2,168,000 feet of cable

The Marshalltown Generating Station (MGS) project will make the state’s air cleaner for decades while creating good-paying jobs in Iowa, said Schmidt.

The 650-megawatt, combined-cycle, natural gas-fired facility is expected to power more than 500,000 homes. It is creating long-term environmental benefits and economic opportunities as well.

Combined with retiring older coal-fired units that are no longer cost-effective to operate, the natural gas-fired MGS will improve air quality. Natural gas-fired generation has the ability to ramp up and ramp down quickly. This provides flexibility to better integrate renewable energy into the electric supply mix.

Proposed rate increase

However, due to the cost of building the facility — an estimated $700 million — and other investments into the service grid — the company said they plan to file a electric rate only increase with the Iowa Utility Board.

Schmidt said the last increase was six years ago.

Beginning in April, customers can expect to see their electric bills increase by $3 to $5 a month.

In about one year, the utility company expects monthly rates for the average customer to have gone up by $12 to $14 total.

Schmidt said the 10 percent to 12 percent rate increase represents about $2.5 billion in capital investments into the electrical system.

“The proposed rate increase is driven by our ability to fund the great work we do,” Schmidt said. “To provide the reliable service — an clean energy — our customers depend on.”

Alliant’s average customer bill is about $113 and the utility services about 500,00 customers, said Schmidt.

“We cover more than 37,000 square miles and to serve that our grid has over 20,000 miles of distribution lines … that’s almost enough to go around the equator.”

Base rate increases are for Alliant’s electricity customers only. Base rates, which cover service costs, maintenance and utility equipment costs, make up about 60 percent of a residential customer’s bill, said Schmidt. The remaining 40 percent is for actual energy costs.

In addition, Schmidt said Alliant also will expand some offerings for customers, including those for limited income customers or electric vehicle rebates.

Alliant customers will receive public notices April 3 regarding the rate increases. Alliant will file that same day with the Iowa Utilities Board, with the first interim rate increases taking place within 10 days.

Eight town-hall sessions will be held around Iowa in late May and early June for interested customers, Schmidt said. The utilities board and the Office of Consumer Advocate also will have representatives at the meetings.

A session is planned in Marshalltown 5:30 p.m., June 9 at the Orpheum Theater.