SunZia, billed as the largest U.S. renewable project, is fully online after 18 years

June 2026 — Pattern Energy said on June 18, 2026, that SunZia, a wind farm and long-distance power line it calls the largest renewable energy infrastructure project in U.S. history, is fully operational. Here's what happened, what it cost, and what went wrong.

Cost and outcome (as of June 19, 2026)

Outcome: fully operational, delivering power from New Mexico to Arizona and the western grid. (Pattern Energy)
Cost: total cost not stated by Pattern or Hitachi Energy.
Scale: about 3,650 MW of wind; the HVDC line carries up to 3,000 MW. (Pattern Energy; Hitachi Energy)
Timeline: more than 18 years in the making; construction began September 2023. (Pattern Energy)

What it is

SunZia pairs an approximately 3,650-MW wind project with a 550-mile high-voltage direct current line, and Pattern says at full capacity it can supply about one million homes a year, delivering more power than the Hoover Dam. (Pattern Energy)

Hitachi Energy says the ±525 kV bipolar link, the largest voltage-source-converter HVDC installation in the U.S., carries 3,000 MW across roughly 550 miles of overhead line and will serve around 3 million people across the Southwest. (Hitachi Energy)

Pattern calls it one of the first major HVDC systems built in the U.S. in a generation, with converter stations at each end. (Pattern Energy) Hitachi says it is the third HVDC Light system it has commissioned in the U.S. and Canada in six months, adding a combined 5,450 MW. (Hitachi Energy)

Who buys the power

The project is fully contracted, Pattern says. Clean Power Alliance, which called itself SunZia's first major customer, said its nighttime wind complements solar and storage. Ava Community Energy said SunZia adds over 250 MW to its portfolio, and San Francisco's utility said its agreement could power nearly 100,000 homes. (Pattern Energy)

Central Coast Community Energy, which serves 1.2 million people, said SunZia provides renewable generation outside peak solar hours. HASI said it was a financial partner. (Pattern Energy)

"Large-scale transmission is essential to meeting the West's growing energy needs," said Elliot Mainzer, CEO of the California Independent System Operator. (Pattern Energy)

Hitachi says fast power-flow control helps address the evening "duck curve," when solar output drops while demand stays high, and estimates about 9 million metric tons of CO₂ avoided in the first full year. Ultra-fast AC choppers paired with the converters are designed to protect grid stability during weather disruptions or other unexpected events. (Hitachi Energy)

The long road

"SunZia proves that we can still build the consequential infrastructure this country needs," said Pattern CEO Hunter Armistead, adding that it was built "on time and on budget." (Pattern Energy)

"Through a whole series of obstacles spanning over a decade and a half, we kept working to move it forward," said Sen. Martin Heinrich of New Mexico, who called it a milestone more than 18 years in the making. (Pattern Energy)

Pattern projects $1.3 billion in direct payments to local governments, schools, counties and landowners over 30 years. (Pattern Energy)

In February 2026, the EIA expected SunZia to start commercial operations that year and said it would be the largest onshore wind project in the United States. (EIA, Feb. 2026)

What went wrong

Eighteen years. Heinrich called full operation a milestone more than 18 years in the making, after 'a whole series of obstacles.' (Pattern Energy)
Numbers don't line up neatly. The wind farm is about 3,650 MW, but the line carries up to 3,000 MW. Pattern counts about one million homes; Hitachi counts around 3 million people. (Pattern Energy; Hitachi Energy)
No cost given. Neither release states what SunZia cost to build.
What we don't know yet: SunZia's actual output and line use in its first year, and the total build cost.

Our follow-up question for Pattern Energy

What did SunZia cost in total, and how much of its 3,650 MW can the 3,000-MW line deliver at peak?

Sources

Pattern Energy, “SunZia comes online, transforming power delivery in the United States,” June 18, 2026. patternenergy.com
Hitachi Energy, “Hitachi Energy celebrates the inauguration of Pattern Energy's SunZia project,” June 19, 2026. hitachienergy.com
U.S. Energy Information Administration, “New U.S. electric generating capacity expected to reach a record high in 2026,” Today in Energy, Feb. 20, 2026. eia.gov

Disclosure: [not in copy] Editor placeholder