Holcomb Station Emissions
The H1 generating unit was initially equipped with a state-of-the-art sulfur dioxide (SO2) scrubber. At the time of its construction in 1983, it was the largest scrubber of its kind in the world. This scrubber is especially practical for removing SO2 from the gases that result from the combustion of low-sulfur coal like that which is burned at H1. This scrubber, in addition to removing SO2, is particularly effective in controlling the sulfur trioxide (SO3) precursor to sulfuric acid mist and the other acid gases that can react in the atmosphere to form fine particulate matter. In conjunction with the scrubber, the fabric filter (baghouse), which is used to control particulate matter in the stack gases, is excellent companion equipment. Together they serve to control the release of hazardous air pollutants from the stack.
H1 is a zero-discharge facility for waste-water. Industrial facilities, in general, and power plants specifically, discharge waste-water to a nearby streams or rivers. However, at Holcomb all water is recycled or reused for purposes that would otherwise require the pumping of additional groundwater. The dirtiest waste water at the plant is used for procedures that do not require cleaner water, leaving the cleanest waste-water to be treated and reused for cooling water purposes, the largest use of water at the site. Few power plants are designed to optimize water use as has been done at H1. The proposed Holcomb Expansion Project would utilize much of the same equipment as has already been installed to treat waters for H1.
In 2011, H1 was fitted with state-of-the-art Hitachi low NOX burners. H1 underwent a 7-week outage to allow for the LNB technology to be installed. During the outage a separate over-fire air system (OFA) was also installed at a cost of $22 million. This environmental control technology reduced the unit’s NOx emission by nearly 50 percent and ensures the unit meets the stringent regulations related to the Cross State Air Pollution Rule (CSAPR).
In 2014, H1 was fitted with equipment to store and inject Powder Activated Carbon (PAC), which reduces mercury emissions in coal-fired boiler flue gases. The technology works by injecting PAC from a storage silo into the flue gas ductwork where it absorbs mercury and is collected along with fly ash in the plant’s particulate collector. PAC testing commenced in 2016 and ensures that H1 is in compliance of the Environmental Protection Agency’s Mercury Air Toxic Standards.