One of the cleanest coal plants in the nation
Bechtel built the Prairie State Energy Campus, the largest greenfield coal-fired power plant built in the United States since the early 1990s. By combining highly-efficient pulverized coal technology and supercritical (extremely high-temperature and pressure steam cycle) boilers with advanced-emission controls, Prairie State’s carbon-dioxide emissions are 15 percent less than those emitted by comparable plants.
Comprising two 800-megawatt power units southeast of St. Louis, Missouri, Prairie State is fueled by coal from a mine at the site. Electricity from the plant is distributed to eight Midwestern-based public power utilities serving nine states. The utilities, along with coal producer Peabody Energy, own the facility. The power plant has an output capability, which is almost 2 percent higher than its nameplate capacity and almost 2 percent more efficient.
Prairie State commissioned a study by the University of Illinois that estimated Prairie State's economic impact on the region at more than $785 million annually.
How it works
Building Prairie State Energy Campus was an important step toward creating a sustainable and secure energy future for the United States. It uses domestic coal resources and clean-generation technologies to produce electricity in a more efficient and environmentally-friendly manner.
Prairie State's coal comes from a mine located across the road from the power plant. Coal travels on conveyors from the coal field to the plant, cutting out the need for transport by rail or barge. This significantly reduces emissions and saves on transportation costs.
The plant uses coal that’s been pulverized to about the consistency of talcum powder and used as fuel for a boiler to heat water and produce steam. The steam drives a turbine, which, in turn, drives an electrical generator, sending electricity throughout the grid to Midwest families and businesses.
Clean electricity through technology
Five technologies were used to improve sustainability of the plant. They include:
- Nitrogen oxide controls
- Selective catalytic reduction, which reduces NOx to state-of-the-art values
- Dry and wet electrostatic precipitators, which eliminate 99.9 percent of particulates
- Sulfur-dioxide scrubbers, which remove SO2 from the flue gas
- Powdered-activated-carbon injection, which removes 90 percent of the mercury emissions