The Western Spirit transmission line is a 241km-long, 345kV AC transmission line to deliver approximately 800MW of wind power from central New Mexico, US to the existing grid in the north-western region of the state.
The project is being jointly developed by Pattern Energy and the New Mexico Renewable Energy Transmission Authority (RETA).
Pattern Energy announced the financial closure and the start of construction works on the project in January 2021.The project will be taken over by the Public Service Company of New Mexico (PNM) upon the completion of its construction at the end of 2021.
The power transmission project is estimated to cost approximately £264.1m ($359.2m). It is expected to create more than 300 jobs during peak the construction phase and supply enough electricity to power approximately 590,000 homes when it enters service.
The transmission line is being constructed in conjunction with Pattern Energy’s Western Spirit Wind power projects totalling 1,050MW in Guadalupe, Lincoln County, New Mexico.
Western Spirit transmission route and design
The Western Spirit transmission line will originate in Santa Fe County and proceed south to the expanded PNM Clines Corners switching station. It will pass through Torrance, Socorro, Valencia and Bernalillo counties before terminating at the new Pajarito switching station in the western side of Albuquerque within Bernalillo County, where it will interconnect PNM’s transmission system.
There will be two intermediate stations along the project route, the Western Spirits switchyard station interconnecting the wind generation project in Torrance County and a new mid-point series compensation station (Abo station) in Socorro County.
The transmission line will be mounted over either steel H-frame or mono-pole tower structures while the width of the right-of-way will be approximately 150ft.
Interconnection to PNM’s transmission system
The existing Clines Corners switching station will be expanded to interconnect the northern portion of the Western Spirit transmission project. The western portion of the project will be interconnected to a new 345kV Pajarito station, which will loop into PNM's existing 345kV West Mesa-Sandia line.
The West Mesa-Pajarito-Sandia 345kV line will be upgraded to 1195MVA to accommodate the Western Spirit project.
MMR Constructors and EC Source were awarded a contract to construct the Western Spirit transmission line in September 2020.
GE Energy Consulting performed the power system and equipment studies for Pattern Energy to support the construction of the Western Spirit transmission line, the associated wind farms, substations, as well as the series capacitor bank.
Western Spirit transmission project background
The New Mexico RETA identified the Western Spirit transmission line as beneficial to the New Mexico grid in 2010 and began development of the project in 2013.
The Bureau of Indian Affairs (BIA) issued a grant of easement for the relevant portion of the project in March 2017 while the Bureau of Reclamation issued a finding of no significant impact in 2018.
The US Federal Energy Regulatory Commission (FERC) granted Pattern Development, an affiliate of Pattern Energy Group, the authority to sell transmission rights on the project in June of 2016. Pattern Energy partnered with New Mexico RETA to accelerate the project development in May 2018.
PNM signed an agreement with the New Mexico RETA and Pattern Development to acquire the project for approximately £220m ($285m) in May 2019.The acquisition was approved by the New Mexico Public Regulation Commission (NMPRC) in October 2019.
The power transmission project is expected to strengthen PNM’s existing system and provide capacity upgrades to enable the transfer of approximately 800MW of new wind power.