The SunZia wind farm and transmission line now under construction across New Mexico and Arizona is a case study of the perils and promise such ambitious projects present in today’s dynamic energy marketplace. 

It’s getting built

Combined, the effort has an $11 billion price tag, incorporating the cost to construct more than 900 wind turbines along with a 550-mile high-voltage direct current (HVDC) transmission line designed to carry up to 3,000 megawatts (MW) from New Mexico’s wind-rich desert to Phoenix and California. It’s an example of the kind of big thinking many power planners say we need more of to help decarbonize our grids—and of the many challenges developers face.

By the time SunZia is operational in 2026, it will have been 20 years in the making. That might have been six years before Californians started hearing the phrase “duck curve” to describe the drop-off of solar generation in late afternoon, but that’s just the scenario SunZia was designed to address. New Mexico has one of the nation’s most abundant and consistent wind supplies—it generates about 30% of its power from wind. When completed, the 3,000-MW transmission lines will provide Arizona and California with enough carbon-free electricity for up to 3 million homes when solar generation lags.

Specialized technology

Transporting that kind of capacity over such a long distance requires specialized technology, which is where the HVDC design comes in. These lines operate more efficiently than traditional high-­voltage AC wires, losing much less energy to waste heat (so no sagging lines during scorching summers). Additionally, this project will incorporate one of the world’s highest-­capacity voltage source converter systems, which will convert AC power from the wind farm to DC for transmission, and then back to AC at the receiving terminals. More often used in undersea applications, this will be its first use in an overhead line installation.

The birds and other concerns

Another aspect that sets SunZia apart is that it’s actually getting built. The challenges it has faced over the last 20 years aren’t unusual, but the fact that the project has made it past those hurdles stands out. Licensing efforts began in 2006, with the original route adjusted due to proximity to the U.S. Department of Defense’s White Sands Missile Range. It was approved in 2015, but required subsequent permitting across multiple counties, states and federal agencies, with nongovernmental environmental groups also weighing in, including Audubon Southwest, the regional branch of the National Audubon Society, due to passage through sensitive bird habitats.

That group initially opposed the line, but worked with Pattern Energy, the project’s owner, to research other options. These included adjusting the route to take advantage of existing lines’ rights-of-way rather than cutting new paths through undisturbed desert environments. Additionally, Pattern Energy will be using an ultraviolet light system Audubon developed to make the infrastructure more visible to birds. 

These revisions earned Audubon Southwest’s approval, and the national organization now cites the project as an example of successful cooperation with transmission developers. Audubon has also launched a program to improve transmission policy and planning, noting the dangers climate change poses for birds and other wildlife, and the need to build out renewable resources to slow down the rate of change.

However, local Native American tribes and environmental groups continue to challenge the project. These legal efforts have focused on Arizona’s San Pedro Valley, where indigenous people have lived for more than 12,000 years. 

The area is rich with archaeological remnants of past cultures, and the Tohono O’odham Nation, along with others, has sued the Bureau of Land Management for approving the project without adequate archaeological study. The case was dismissed in June, but an appeal is underway.

In July 2024, the Biden administration issued new permitting rules that outline strict deadlines for federal agencies to complete environmental assessments and impact statements. However, such rules may be reviewed and changed by the current administration—and the Biden team’s efforts also involved changes to revisions made during the first Trump administration. Broader, bipartisan legislation to ease permitting for a range of energy projects, including mining and liquid natural gas exports, made it out of a Senate committee last fall, but was never voted on.

Another hurdle to similar projects was raised with a January executive order Trump signed, which halts all leasing of federal land and waters for new installations and directs federal agencies to stop issuing permits for all new wind projects, until a government review of the industry can be conducted.

Pattern energy