The Project’s generation unit is designed to use sub-bituminous, low-sulfur Powder River Basin (PRB) coal. The PRB is a proven source that offers a long-term, stable, and economical supply of low-sulfur coal. Coal purchases will be made through a competitive bid process from one or more PRB coal suppliers.
Coal will be delivered to the facility by rail. Once the Project is completed, Holcomb Station will, on average, receive one unit train per day. The existing coal storage yard will be expanded to accommodate the fuel needs of both units. From the coal storage yard, coal is transferred by a conveyor network to fill the coal pulverizer silos. Once the coal is pulverized, fans blow it through low-nitrogen oxide (NOx) burners into the steam generator where it is burned.
Supercritical Steam Generators
The steam generator in the Project’s unit will be comprised of water-filled tubes lining the furnace walls. Coal that enters the furnace will be ignited and burned. The burning coal releases thermal energy that is absorbed by the water in the tubes. The temperature of the water rises and is converted directly into a supercritical fluid with properties similar to steam. The steam is then piped to the steam turbine.
The steam turbine’s rotating blades are attached to large shaft that is connected to the main generator. As the steam passes through the turbine, pressure and thermal energy from the steam are converted into rotational mechanical energy, causing the turbine shaft to spin the electric generator. The generator converts this mechanical energy into electric energy.
After the steam passes through the turbine, it exhausts into the condenser where it is cooled and changes from a vapor back into liquid. This water is then pumped back to the steam generator to repeat the cycle again.
Air emissions will be minimized through various control technologies. Sulfur dioxide (SO2) emissions will be controlled with a dry-lime Flue Gas Desulfurization (FGD) system.
Particulate emissions will be controlled with a fabric filter baghouse that removes more than 99.9 percent of the particulate matter or dust. NOx emissions are controlled with a combination of low-NOxburners, Overfire Air (OFA), and a Selective Catalytic Reactor (SCR).
Mercury emissions will be controlled through the use of a Powdered Activated Carbon (PAC) injection system. The PAC is injected into the steam generator exhaust gas upstream of the FGD system and collected in the baghouse.
The flue gas from the steam generator passes through the SCR, PAC injection system, FGD, and fabric filter emissions control systems before large, induced draft fans exhaust the flue gas through the stack. The 625-foot stack, equipped with a continuous emissions monitoring system, will consist of an outer concrete wind shell and an inner flue.
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The Project will be interconnected to the western electricity grid, requiring construction of an AC/DC/AC converter station to transfer electricity back to the eastern electricity grid for Kansas consumers.
The Project will support the construction of new extra-high voltage transmission lines from Kansas to the western U.S. electrical grid, creating the potential to export Kansas renewable and base load energy to western markets.
Western-tied transmission lines will not be built without the Project because traditional transmission developers cannot afford to build such lines without the steady transmission revenues from a base load plant.
Local Construction and Operation Impacts
The partners are committed to working with local communities on issues related to the construction and operation of the Project. Sunflower, Tri-State, Golden Spread—along with the Project’s engineering, procurement, and construction contractor—will work closely with communities to address issues of local concern.