Arizona Corporation Commission’s Vote Ensures Continued Development of Massive SunZia Transmission Wind Project in New Mexico, Arizona

SunZia Transmission and Wind, the largest renewable energy project in the western hemisphere, will bring renewable power to 2.5 million customers.


PHOENIX (November 9, 2022) Western Resource Advocates commends a unanimous decision by the Arizona Corporation Commission (ACC) today that allows SunZia Transmission to move forward with the development of a transmission project that will carry wind-generated electricity from New Mexico to Arizona.

In July, the Pattern Energy Group acquired the SunZia Transmission project from SouthWestern Power Group. Pattern Energy is developing the SunZia Wind project, a 3,000 megawatt facility in New Mexico, which will utilize the 550-mile SunZia Transmission line to provide affordable and reliable renewable electricity for an estimated 2.5 million customers in central New Mexico and south-central Arizona. SouthWestern Power will develop a second line, El Rio Sol Transmission, parallel to SunZia’s. The combined lines will bring 4,500 megawatts of power to the two states and for export to Western markets.

“SunZia will be the largest wind project in the Western hemisphere, and with the Commission’s latest approval, we’re thrilled to see development move forward,” said Adam Stafford, Western Resource Advocates’ managing senior staff attorney in Arizona. “Arizona and New Mexico are already experiencing the impacts of climate change, and our window to combat this by reducing greenhouse gas emissions is closing quickly. We need to take action now, and building the SunZia lines helps us move in the right direction.”

The ACC approved SunZia Transmission’s certificate of environmental compatibility on Feb. 16, 2016. In May, the group requested that the Commission amend the certificate to authorize the use of updated power pole structures, divide the approved certificate to allow separate ownership of the two lines, and to extend the expiration date of the certificate for SunZia’s line by two years, to February 2028. On Oct. 17, WRA filed a brief in support of SunZia’s request, urging the ACC to approve the amendments; today’s 5-0 vote by the ACC granted them.

The SunZia line will avoid nearly 17 million metric tons of annual CO2 emissions. Pattern Energy is developing the SunZia Wind project in Lincoln, Torrance, and San Miguel counties in New Mexico. The company is expected to begin operations in 2025; SouthWestern Power is expected to bring El Rio Sol online by 2031.


James Quirk, 908-902-3177,

2° Out West Podcast


Important updates from WRA’s experts – straight to your inbox.

Western Resource Advocates