Simulation of the potential impacts of the proposed Sithe power plant in the Four Corners basin using CAMx

The Diné Power Authority (DPA) has contracted with Sithe Energies, Inc., (Sithe) to develop a 1500 MW green field power plant located on Navajo Nation trust land southeast of Shiprock, NM in the Four Corners basin. This would be a large point source emitting 3,319 tons per year (tpy) of sulfur dioxide (SO2), 3,325 tpy of nitrogen oxides (NOx), 1,120 tpy of particulate matter (PM10), and other pollutants. The Four Corners basin is located on the Colorado Plateau, home to Grand Canyon National Park (GRCA) and other class I areas, where visibility is an integral component of a visitor’s experience. There is concern that the proposed power plant will cause or exacerbate existing haze on the Colorado Plateau. Past monitoring and modeling studies have shown that power plants located to the east and west of the Grand Canyon can significantly contribute to haze in the Grand Canyon NP. Power plants to the east of the Grand Canyon had their largest contribution to haze during the winter months, when pollutants that reached Lake Powell drained down the Grand Canyon following the Colorado River to Lake Mead. The Four Corners basin is to the southeast of the Grand Canyon NP and other class I areas in Utah including Canyonlands NP, Capitol Reef NP, and Arches NP. This study investigates the potential impacts of the Sithe power plant on class I areas locate