The largest wind energy project in U.S. history is now online, delivering power from a massive array in New Mexico to Arizona and California — and signaling a new era for sending clean electricity across the West.
Nearly two decades in the making, the estimated $11-billion SunZia project from Pattern Energy is now fully operational, company officials said Thursday. It’s made up of 916 turbines that can produce up to 3.65 gigawatts of electricity, making it potentially more powerful than the Hoover Dam.
It’s also more than three times bigger than either of the next two largest U.S. wind farms, Alta Wind in Kern County and Great Prairie in northern Texas, according to the U.S. Energy Information Administration.
It’s a scale that would have been difficult to imagine even a decade ago.
Crucially, the project also includes a 550-mile high-voltage direct-current transmission line that delivers wind power from New Mexico to the Palo Verde substation in Arizona, where it then feeds into Southern California. In all, some two-thirds of the power sent across the line will be delivered to the state.
Experts say the project already has begun making a difference on the grid: Since SunZia began testing in April, the state’s Independent System Operator, CAISO, has reported record-breaking amounts of wind power on the California grid at least five times, according to Dennis Wamsted, an energy analyst at the Institute for Energy Economics and Financial Analysis.
Wind output on May 15 hit a record 8,294 megawatts — almost 1,600 megawatts higher than the record before SunZia power began flowing into the state, he said.
“This is a milestone, there’s no doubt about it,” Wamsted said. “They’re tapping into a great wind resource in New Mexico, and that wind resource is now going to be used across the Southwest. It’s good for consumers everywhere, and it’s really good for folks who are in favor of a transition away from fossil fuels.”
The New Mexico region was selected in part for its strong and consistent winds, comparable to those off the coast of Morro Bay.
Much of it will come when the wind picks up at night, complementing California’s abundant daytime solar power, and batteries, which discharge for a few hours around sunset.
But it’s not only a benefit for California. The project reflects a renewed effort to move large amounts of remote wind or solar power to high-demand population centers across multiple states.
“Large-scale transmission is essential to meeting the West’s growing energy needs and strengthening reliability across the grid,” said Elliot Mainzer, CAISO’s president and chief executive, in a statement. “Projects of this scale help deliver energy reliably to areas of rising demand, improve the movement of power across states and support a more resilient, flexible and affordable electric system.”
It also comes at a critical moment. While many countries, including China, are investing heavily in renewable energy including wind, solar and battery energy storage, the U.S. has pulled back on these under the Trump administration, which has prioritized fossil fuels such as oil, gas and coal in its mission to “unleash American energy.”
The president has especially targeted offshore wind, striking a series of multimillion-dollar deals with energy developers to walk away from offshore wind leases in federal waters and instead invest in domestic fossil fuel and geothermal projects. Two of those abandoned leases have been off the coast of California’s Morro Bay.
The data show land-based wind, such as the SunZia project, already is cost competitive with other major new-build power sources in the U.S. Despite Trump’s approach, red states have continued to expand their wind power, such as Texas, which now leads the nation in the development of wind and solar power as well as battery storage.
Iowa, Oklahoma, Kansas and Illinois have invested heavily in wind, while Wyoming is developing a 3,550 megawatt wind farm, the Chokecherry and Sierra Madre Wind Energy Project, that will export wind power to Western states including California.
“The administration cannot stop the transition,” Wamsted said. “The market [is] moving toward renewable energy.”
The SunZia project faced a long road to completion with ownership changes, slow permitting processes and major redesigns since it was first conceived in 2006. Pattern Energy acquired the project in 2022.
“SunZia proves that we can still build the consequential infrastructure this country needs,” Hunter Armistead, chief executive of Pattern Energy, said in a statement, noting that “many thought this was too big and too complex to finish.”
There was opposition, including from environmental groups concerned about habitat fragmentation, effects on bird migration and other disturbances from construction of the transmission line, which crosses the San Pedro River Valley, an important migratory flyway and river corridor in the Arizona desert.
Perhaps the most significant opposition came from groups concerned about cultural and architectural sites along the transmission path. The Center for Biological Diversity, the Tohono O’odham Nation, the San Carlos Apache Tribe and the nonprofit Archaeology Southwest challenged the project in court, contending that the developers did not comply with historic preservation rules and that the project will cause irreversible damage to sensitive areas.
“Instead of taking the landscape-level impact into consideration in planning and designing the power line, they basically did a slalom course through the places where there were occurrences of environmental sensitivities and cultural sites,” said John Welch, vice president of preservation and collaboration at Archaeology Southwest and a professor at Simon Fraser University. “And this is especially true for the San Pedro Valley, which for decades now has been well known as a place of exceptional cultural significance.”
Welch said a motion for summary judgment is still pending in the U.S. District Court in Arizona, which the groups hope will require the developer to undo parts of the project or otherwise address their concerns.
But others see it as a huge victory for the region and the U.S., including Sen. Martin Heinrich of New Mexico, the top Democrat on the Senate Energy and Natural Resources Committee, who was instrumental in ushering SunZia to completion over the course of nearly 20 years.
Reached by phone Thursday, Heinrich said he believes SunZia is a model for big infrastructure projects in the U.S. It also demonstrates that transmission is a constraint that can be addressed.
“We’re at a point now where it’s fairly straightforward to site and develop new generation — be it wind, solar, batteries, etc. — but getting the electrons where they need to go is the limiting factor in many of these cases,” Heinrich said. “Demand is on the rise for the first time since air conditioning became commonplace, so transmission is important to be able to solve for that.”
The project also underscores the need for permitting reform to help expedite the planning and approval process for similar projects moving forward, the senator said.
“My hope is that we can take this project, lift it up as an example, and apply some of those lessons more broadly,” he said, adding, “we need to be able to do multiple SunZias.”
