Alliant power plant rendering

This rendering, provided by Alliant Energy, illustrates the Madison utility's proposal to build a 650-megawatt, natural gas-fueled power plant in the town of Beloit. An array of solar panels, shown in front of the proposed power plant, would help run the facility.

Rendering provided by Alliant Energy

The new power plant Alliant Energy plans to build in the town of Beloit will use natural gas to create electricity for its customers, but the plant itself will be run, in part, by solar power.

The Madison utility company released specifics Friday on the proposal initially revealed last November. It calls for building a 650-megawatt natural gas-fired power plant, able to serve more than 500,000 homes, fronted by an array of solar panels — a new element of the plan.

The new power plant would be built next to the existing 675-megawatt, natural gas-fueled Riverside power plant. Its waste heat from the generation process would be captured and turned into additional electricity.

The project would cost an estimated $750 million.

The solar panels would be enough to produce about 2 megawatts of electricity — at a cost of $9 million — and will offset part of the utility’s energy needs.

It would be the second-biggest solar field in Wisconsin, behind only Epic Systems Corp.’s panels, which can produce up to 2.2 megawatts of power for the Verona electronic health records company, said Tyler Huebner, executive director of RENEW Wisconsin.

“We applaud Alliant for moving into this space,” Huebner said. “We’ll look very closely at the cost of the installation but many other states are finding solar to be a very cost-effective option.”

“Integrating solar and natural gas generation is a new technology application for us,” said John Larsen, president of Alliant’s Wisconsin utility. “We are eager to use it as a research and learning tool, collaborating with local schools, colleges, the Electric Power Research Institute and industry partners.”

Huebner said his organization will review projections for the state’s future energy needs and options that will offer “the lowest cost, lowest risk and highest benefit” to customers.

Katie Nekola, attorney for Clean Wisconsin, said she’s not sure building a power plant that big makes sense.

“It’s a large project. We will be taking a close look at it and looking at the need for it, and looking at what alternatives might be available to meet that need,” she said. “Electric demand is down in the state.”

Nekola said she’d like to see Alliant invest even more in solar power.

“I’d much rather see a lot more megawatts of solar and a lot fewer megawatts of gas,” she said.

Alliant spokesman Scott Reigstad said a bigger solar investment might be possible. “We are exploring additional solar power on the site, as part of our plans to further modernize the location. Through our experience with this installation, it will further educate us on the future potential for solar generation expansion — either at this site or others,” he said.

Alliant said the project would replace 700 megawatts of aging power plants scheduled to close, and it would provide more efficient generation.

The new natural gas plant is expected to run about 50 percent of the time, on average, year-round, but in the summer months, when people crank up their air conditioners and electricity demand soars, the facility could be operating 75 to 80 percent of the time, Reigstad said.

Alliant submitted its proposal to the Wisconsin Public Service Commission on Friday. The PSC will conduct an analysis and will seek public comment before making a decision, probably next spring.

If approved, construction is expected to begin in the summer of 2016 and the project should be ready in early 2019.


Judy Newman is a business reporter for the Wisconsin State Journal.