Hitachi Energy celebrates the inauguration of Pattern Energy’s SunZia project, now delivering clean, reliable power to millions across the American Southwest

Marking a major milestone for transmission infrastructure in the United States, Hitachi Energy, a global leader in electrification, together with Pattern Energy, a leader in clean energy and transmission infrastructure, have announced that the new SunZia Transmission line is now fully operational and delivering power to customers throughout the Southwest.

This high-voltage direct current (HVDC) link transmits 3,000 MW of clean power from the SunZia Wind generation site in New Mexico across roughly 550 miles of overhead lines through remote terrain to the power grid in Arizona. Helping address fast-growing electricity demand in the U.S., the project will supply power to around 3 million people across the Southwest, while supporting rising electricity demand driven by data centers, electrification, and industrial growth.

SunZia Transmission uses Hitachi Energy’s HVDC Light® technology, a state‑of‑the‑art Voltage Source Converter (VSC)-based solution with advanced power electronics to precisely control voltage and power flow. Engineered for long‑distance, high‑efficiency transfer of power with minimal losses, this technology improves grid stability and enables the smooth, reliable integration of energy generated by SunZia Wind.

Hitachi Energy applied its unmatched project execution capabilities, honed through the deployment of some of the world’s biggest and most complex energy infrastructure projects, to successfully deliver SunZia Transmission. This ±525 kilovolt (kV) bipolar HVDC link is the largest VSC-based HVDC installation in the United States and one of the largest worldwide. 

SunZia will also help balance energy supply and demand, addressing the ‘duck curve’¹ that occurs when solar generation drops in the evening and demand for electricity remains high. The VSC based HVDC system can rapidly adjust power flow, allowing the grid to respond quickly to changing conditions while delivering more wind energy precisely when it’s needed, reducing reliance on fossil fuel plants during peak periods. Paired with ultra‑fast AC choppers, the system is designed to protect grid stability, ensure reliable, consistent energy delivery even during weather disruptions or other unexpected events.

Advancing progress toward Arizona’s energy independence, SunZia is expected to avoid approximately 9 million metric tons of CO₂ in its first year of full operation. This is the equivalent of removing three million gasoline-powered cars from the road for an entire year².

SunZia is the third major HVDC Light project commissioned by Hitachi Energy in the United States within the last 6 months, significantly strengthening the grid at a time when demand growth is outpacing supply.