Start 2: Weston Power Plant Unit 4
Cost: $752 million

The increasing demand for electricity is driving the 530-MW Weston Power Plant Unit 4 project in the Central Wisconsin towns of Kronenwetter and Rothschild.

Low sulfur coal from Wyoming's Powder River Basin was selected as the fuel to drive a turbine that will produce Unit 4's energy, said Philip Hayes, project manager for Green Bay-based Wisconsin Public Service Corp., the owner.

The choice of fuel has environmental benefits over alternative coals because fewer oxides are released in the air after low sulfur coal is burned.

Systems will be installed to ensure air quality, including a selective catalytic reduction unit, a dual train dry scrubber, baghouse and mercury control system that is reportedly the first of its kind in Wisconsin.

Emissions will be "very restrictive" in nitrous oxides, sulfur and mercury, Hayes said. For instance, the plant will produce an average of about 0.06 lbs. of NOx per million British thermal units of fuel over a 12-month period.

About 10 structures will be built, including a water treatment facility, lime preparation building and 500-ft.-high stack. The biggest structures will be the boiler and turbine buildings.

A substantial amount of sitework went into the project.

After topsoil was removed, an engineered soil was laid beneath the turbine and boiler buildings. The engineered soil provides resistance against the buildings' differential settlement due to the heavy loads inside.

"There are voids between the sand granules, so it (the engineered fill) makes the sand particles adhere to each other," he said.

About 15,000 tons of fly ash was mixed with the local sandy soil, Hayes said.

Winter Concrete Pouring

Cold weather concrete forming techniques were used to make the continuous foundation for the boiler and turbine buildings.

About 65,000 cu. yds. of concrete will be used to form the foundation that is about 300 ft. long, 200 ft. wide and 8 ft. deep.

The forming techniques included warming the aggregate and water used in the mixing, erecting a tent and using heaters.

About 11,000 tons of structural steel will be used to form the structure, and the erection was expected to start in May. Once the steel is erected, the boiler and turbine can be installed.

Unit 4 will connect to the Gardner Park Road substation that will link to the Arrowhead-Weston transmission line under construction between Wausau and Duluth, Minn.

Return to Top of 2005 list