Phoenix, Ariz. —  The Arizona Corporation Commission stands in support of the recent collaboration among the state’s three largest electric utilities in committing to the Transwestern Pipeline Desert Southwest Expansion Project.  The new natural gas pipeline will help maintain the delivery of reliable and resilient energy by transporting natural gas from the Permian Basin in West Texas to Arizona.  Construction is expected to be completed by late 2029.

“Arizona’s energy needs are growing drastically, which is why it is so important for the state’s utilities to anticipate and prepare for the future,” said Chair Kevin Thompson. “For years, Arizona residents and the state’s economy have benefitted from one of the most reliable energy grids in the country. I applaud APS, City of Mesa, SRP, TEP and UniSource for their commitment to maintaining this reliability and helping to secure Arizona’s energy dominance.”

“With this new natural gas pipeline, Arizona will be well positioned to have reliable baseload power to meet the growing demands of our economy,” said Commissioner Rachel Walden.  “I’m pleased to see that the City of Mesa is participating in this project, serving as an example of Arizona’s ability to attract new commerce with affordable power while innovating in water conservation.”

As the demand on Arizona’s electric grid continues to steadily increase, so has the utilities net capacity. This has enabled them to keep pace with the state’s continuously growing energy demand and record-high demand peaks, so far.  In the past six months several new utility scale generating units were completed in Arizona, increasing the state’s total net summer capacity by about 1,490 MW, according to the latest U.S. Energy Information Administration’s (EIA) Electric Power Monthly report. The Commission has played a key role in pushing forward new generation and infrastructure projects while monitoring the ever-increasing demand for energy in Arizona.

Over the past 18 months, the Commission has approved nearly 1,000 MW of new or expanded utility owned natural gas plants, for example, the Bella project which added 480 MW, the Redhawk project which added 397 MW, and the Black Mountain expansion project which added 96 MW to the utilities net capacity.  The Commission has also allowed privately financed energy generating facilities to be built, owned and operated by independent power producers (IPPs). Typically, IPPs enter into purchase power agreements with an Arizona utility, adding electricity to the state’s electric grid.  In addition to the Transwestern Pipeline Desert Southwest Expansion Project, several other new projects are currently underway that will further increase Arizona’s energy production and capacity. The Commission has also begun the process of investigating opportunities to build new nuclear power facilities, as well.

Currently, natural gas and coal account for about 50% of Arizona’s electricity generation, renewable sources account for about 29% of generated electricity, nuclear plants produce about 11% of the state’s electricity, and battery storage facilities contribute about 9% of the state’s electricity demands.

"We’ve been working closely with the utilities and the Trump administration for some time to expand Arizona’s natural gas infrastructure, so I’m pleased to see this timely announcement of the Transwestern Pipeline Desert Southwest Expansion Project," said Vice Chair Nick Myers.  "Additional natural gas infrastructure is essential to meeting the state’s growing energy demand in the years ahead."

Vice Chair Myers opened docket G-00000A-25-0029 to inquire into the expansion of natural gas infrastructure and storage in Arizona.  The first Workshop on the topic is scheduled for Tuesday, August 26, 2025, beginning at 9:00 a.m. at the ACC building at 1200 W. Washington St., Phoenix, AZ.   The workshop will also be broadcasted virtually.

The sources of information in this news release can be found in the EIA’s Electric Power Monthly reports at https://www.eia.gov/electricity/monthly/epm_table_grapher.php?t=table_6_03, https://www.eia.gov/electricity/monthly/epm_table_grapher.php?t=table_6_02_a.