SunZia opens solicitation for capacity on 500-kV transmission line

A second open solicitation process has been launched to allocate the approximately 1,500 MW of remaining capacity for the first phase of the SunZia Southwest Transmission Project.

The first phase of the SunZia project will consist of a single-circuit 500-kV high-voltage direct current line, which will primarily deliver renewable energy from southwestern New Mexico and southeastern Arizona to load-serving entities in Arizona, California and other western project markets.

Developer SunZia Transmission awarded the initial 1,500 MW of transmission capacity to Pattern Energy Group LP in August 2016. The current solicitation will be for firm service from the SunZia East AC/DC converter station to the existing Pinal Central substation and the proposed Owl Head substation.

Interested participants may obtain a form at the open solicitation website and submit it via email to SunZiaOS@energystrat.com by Dec. 17. Energy Strategies LLC is serving as the independent third-party solicitation manager.

The transmission project has been in development for 14 years. SunZia Transmission has already completed federal permitting and has secured an Arizona state siting permit. New Mexico regulators, however, denied SunZia Transmission's project application in 2018 without prejudice, allowing the developer to reapply for a permit.

In a 2020 presentation, SunZia Transmission indicated that it was arranging construction financing for the estimated $900 million first phase of the project. The developer expects to start construction in 2023 and achieve commercial operation in late 2025.

The second phase of the project is expected to include an additional 1,500 MW of capacity on 500-KVac transmission lines, as well as additional delivery points. The developer has yet to determine the date to begin construction for phase two and has excluded it from the current solicitation.

SunZia Transmission has also been in discussions with Pattern Energy over the latter acquiring the project to minimize risks. The companies expect to soon file an application with the Federal Energy Regulatory Commission to confirm continued recognition of SunZia Transmission's negotiated rate authority when and if Pattern Energy becomes the upstream owner of the project.