A study being released Thursday will warn of brownouts and blackouts if the largest coal plant in the West is shut down in favor of natural gas-fired electricity.
The study by consultants Quanta Technology and funded by coal giant Peabody was submitted to Arizona’s state utility commission. It supports keeping the Navajo Generating Station open or risk significant dangers from brownouts and blackouts in the region. Peabody supplies the station with coal.
The study shows that Arizona’s dependence on a few natural gas pipelines to supply the entire state would pose a key vulnerability to grid reliability if Arizona were to become overly reliant on natural gas power plants to provide the bulk of its electricity. It also looked at what the reliability hurdles would be if the Palo Verde nuclear power plant in Arizona unexpectedly closed.
The results would be bad on many levels, the study found.
"All three of the unique Arizona scenarios analyzed as separate events including loss of the Palo Verde Nuclear Station, the El Paso Natural Gas Pipeline and the Trans-Western Gas Pipeline were found to stress the Arizona electric grid with unacceptable overloads," according to the study's findings. "Unacceptable overloads are indicative of potential violations to operating criteria that serve as guidelines for reliable grid operation."
The "material impacts" to the grid could lead to "damage to equipment, extended hours of power outage in the region and obstacles to daily activities," the study said.
The biggest disruptions in electricity service would occur in the densely populated areas of Phoenix, Flagstaff, Scottsdale, Vail in Pima County, Tucson, and Raso. California also would feel the impact in the cities of Lugo in Los Angeles County and Shandon in San Luis Obispo County.
The bottom line is: "Without [the Navajo Generation Station] in operation, these conditions led to power deficiencies which could evolve into potential voltage collapse and outages, load shedding triggers, potential rotating brownouts, failing transformers or transmission lines and equipment damage."
The Trump Interior Department is overseeing the plant’s retirement, which originally was slated for the end of this year. Interior Secretary Ryan Zinke managed to keep the plant operating through the end of 2019. The Interior Department is the second-largest owner of the plant.
Peabody is in charge of finding new owners of the plant. It said last month that it got the interest of an unnamed party that is looking to own the plant after the original owners close the station. But the fate of the plant is uncertain.