Four Corners Generating Station

Four Corners Generating Station

Company type	Power plant
Industry	Electric power generation
Founded	1963
Headquarters	Near Fruitland , United States
Area served	Navajo Nation territory, New Mexico, Arizona
Products	Electricity
Owner	Arizona Public Service (majority), Navajo Transitional Energy Company (7%)

The Four Corners Generating Station is a coal-powered power plant with a capacity of 1,540 megawatts, located near Fruitland, New Mexico. It operates on land leased from the Navajo Nation government within the Navajo Nation territory.

Description

Initially, the facility consisted of five units with a combined output of approximately 2,040 MW. In 2014, Units 1 through 3, which together accounted for 560 MW, were permanently retired as part of a $182 million environmental compliance initiative by Arizona Public Service (APS). The remaining two units, Units 4 and 5, each generate 770 MW. The first three units began service between 1963 and 1964, while Units 4 and 5 commenced operations in 1969 and 1970 respectively.

APS held full ownership of Units 1–3 and managed Units 4 and 5, which were co-owned by APS alongside several other utilities. At the outset, ownership shares for Units 4 and 5 were distributed as follows: Southern California Edison (48%), APS (15%), Public Service Company of New Mexico (13%), Salt River Project (10%), Tucson Electric Power (7%), and El Paso Electric Company (7%). Southern California Edison divested its stake to APS in 2013, coinciding with the closure of Units 1–3. Subsequently, El Paso Electric’s portion was acquired by Navajo Transitional Energy Company (NTEC).

The station utilizes Morgan Lake for its cooling needs; this reservoir receives a daily inflow of roughly 28 million gallons sourced from the San Juan River. Coal fuel is transported from the adjacent Navajo Coal Mine through the Navajo Mine Railroad.

NTEC acquired the Navajo Mine from BHP along with three additional mines and secured a 7% ownership interest in the Four Corners Generating Station. In 2020, APS declared intentions to retire the plant entirely, putting at risk both the mine’s operations and the associated railroad infrastructure.

History

The Four Corners Generating Station was constructed on Navajo Nation land under a lease agreement set to expire in 2041. Construction milestones include completion of Units 1 and 2 in 1963, Unit 3 in 1964, Unit 4 in 1969, and Unit 5 in 1970.

An interesting historical note is that astronauts from the Mercury Seven program identified only two man-made features visible from space: the Great Wall of China and the exhaust plume emitted by Four Corners Power Plant.

In 1975, New Mexico enacted a tax targeting electricity generation that was exported beyond state borders. This tax led to two significant cases before the United States Supreme Court. In Arizona v. New Mexico (1976), the court declined to exercise original jurisdiction, deferring to state courts. Later, in Arizona Public Service Co. v. Snead (1979), it was determined that the tax infringed upon the Supremacy Clause of the United States Constitution.

In November 2010, APS revealed plans to purchase Southern California Edison’s stake in Units 4 and 5, implement air pollution control technologies on these units, and retire Units 1 through 3. This acquisition and subsequent shutdown were finalized by 2013, resulting in a reduction of Four Corners’ generating capacity to 1,540 megawatts.

Following litigation initiated by environmental organizations, an agreement was reached in a 2015 consent decree between plant operators and plaintiffs. This settlement mandated reductions in nitrogen oxides and sulfur dioxide emissions, imposed $1.5 million in civil fines, and allocated $6.7 million toward healthcare services and mitigation efforts benefiting affected communities within the Navajo Nation. The lawsuit addressed pollution concerns impacting Class I areas protected under the Clean Air Act, including Grand Canyon National Park and other federally managed sites, as well as health hazards faced by nearby residents.

Decommissioning

In January 2020, Arizona Public Service declared its intention to retire the Four Corners Generating Station by the close of 2031, advancing the shutdown timeline by seven years from the initially planned 2038. This decision supports APS's commitment to achieving zero carbon emissions by the year 2050.

See also

• List of largest power stations in the United States