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Weston 4 Generating Unit
Wisconsin Public Service, our electric and natural gas utility based in Green Bay, Wisconsin, recently built a new, environmentally sound electric generating unit.* The Weston 4 unit, located near Wausau, Wisconsin, is a state-of-the-art 500-megawatt power plant using clean coal technology.
* Wisconsin Public Service owns 70% of the plant, and is the plant operator. Dairyland Power Cooperative owns 30% of the plant.
In March 2008, Weston 4 produced electricity for the grid for the first time. This was part of a methodical start-up process. The unit went into commercial operation on June 30 and is now dispatched according to electric market demand. The company's customers and the community are receiving the benefits of the unit's higher efficiency, operating flexibility and lower carbon dioxide emissions.
Clean-Coal Technology
Weston 4's project team gave careful consideration to the surrounding community, the environment, the financial market, reliable electric generation, maximizing the value of the plant's site, and using world-class experience to design and build the plant. One of the most notable aspects of the project is its use of clean-coal technology.
"Clean coal technology" is defined as using low-sulfur coal, state-of-the-art air quality control systems and supercritical combustion technology. Weston 4 is one of the cleanest coal-fired power plants in the country. In addition, it will be a low cost power producer. Weston 4 was built to fill growing electric needs in the market, and it was the most economically sound solution.
Air
When compared with coal-fired power plants typically in operation, Weston 4's supercritical combustion process:
- Burns fuel more efficiently, resulting in less fuel use.
- Creates fewer emissions.
- Results in less ash.
- Uses lower-sulfur coal.
Weston 4 also uses low nitrogen oxide (NOx) burners on the boiler, a selective catalytic reduction system to control NOx emissions, a dry flue gas desulphurization system for sulfur dioxide (SO2) emission control and a baghouse for particulate matter emission control.
Weston 4 was the first plant in Wisconsin permitted to use "sorbent injection control" to reduce mercury emissions. In 2005, the Environmental Protection Agency (EPA.) finalized new mercury emission standards for coal-burning power plants. Weston 4's mercury limitations are stricter than the EPA's new standards. In addition, the mercury-control technology being used at Weston 4 has been tested as part of a national research project. The project is sponsored by the Department of Energy's National Energy Technology Laboratory, the Electric Power Research Institute and other energy companies.
Approximates 16% of the total costs for Weston 4 were for air-pollution controls.
Land
The Weston 4 unit shares 345 acres with Weston units 1, 2 and 3. Wisconsin Public Service sought community input throughout Weston 4's permitting, licensing and construction to ensure the plant would be a good neighbor to those who live or work nearby.
- During construction, Weston 4 had a goal of recycling 65% or more of all construction waste from the building site. At the end of construction, more than 80% of all construction waste was recycled, and more than 17 million pounds of waste was diverted from a landfill. This was a record-breaking accomplishment in the state.
- The plant is designed with "sound attenuation" features to control noise. Major equipment of the project is enclosed in buildings
- Weston 4 is painted a natural color. Its landscaping includes a buffer area with trees and shrubs to make the site more pleasing to the eye.
Water
Weston 4 uses cooling towers to remove heat from its process. Cooling towers conserve water and ensure that water discharged back into the nearby Wisconsin River does not negatively affect aquatic life.