The Bureau of Land Management (BLM), after a multi-year environmental review process, has released the Final Environmental Impact Statement (EIS) and two related Proposed Resource Management Plan Amendments (RMPAs) for the SunZia Southwest Transmission Project. The full text of these documents can be found here. The relevant Notice of Availability was published in the Federal Register on June 14, 2013. Publication of the Notice of Availability starts the clock running on a 30-day public protest period for the two RMPAs.

The project, proposed by SunZia Transmission, LLC, would involve the construction of two separate 500kv transmission lines in mostly parallel corridors, spanning approximately 515 miles between Lincoln County in south-central New Mexico and Pinal County in south-central Arizona. The capacity of the lines is anticipated to be 3,000 MW on an AC basis, or up to 4,500 MW if the project proceeds under a hybrid AC/DC option. The EIS includes a detailed map indicating four potential alternative locations where the lines could be sited in this general area, including the “BLM Preferred Alternative” route. Approximately 185 miles of the route for the BLM Preferred Alternative would be located on BLM lands.

Originally conceived as far back as 2006, the project is viewed by many as being a vital component of New Mexico’s and Arizona’s efforts to comply with state-mandated renewable portfolio standards. Under current law, New Mexico is required to generate 20% of power from renewables by 2020, and Arizona is required to generate 15% of power from renewables by 2025. The project is also seen as critical for the development of New Mexico’s and Arizona’s substantial solar and wind power resources, as it would enable the delivery of power generated by solar and wind projects in those states across the southwestern U.S., including potentially all the way to Los Angeles. Various sources have estimated that more than 10,000 MW of solar power and 10,000 MW of wind power could be generated from locations in New Mexico and Arizona in close proximity to the proposed transmission lines. Supporters of the project also note that it would substantially improve the reliability and efficiency of the electrical grid in the region.

One interesting difficulty encountered by project proponents was opposition from the U.S. Army, which has expressed concern about the proposed lines’ proximity to the White Sands Missile Range. The White Sands Missile Range, covering almost 3,200 square miles in five counties of southern New Mexico, is the nation’s largest military installation. The White Sands Chief of Plans and Operations noted the possibility that an off-target missile or rocket could strike the transmission lines – which might be as high as 165 feet – potentially resulting in a blackout affecting most of the West coast! In an effort to address these concerns, the BLM Preferred Alternative route would site the project a minimum of 30 miles away from White Sands.

As might be expected, the project has also encountered significant opposition from environmental groups. Much of this opposition is centered around concern for adverse environmental impacts in the San Pedro River Valley in Arizona, which is considered important habitat for a number of species. According to one commentator, the lower San Pedro River Valley – where the Sonoran Desert, Chihuahuan Desert, Madrean and Arizona Mountains eco-regions converge – contains some of the richest species diversity in the U.S. The area is also viewed as a crucial migratory bird route for millions of birds traveling from Central America to the U.S. and Canada.

The BLM’s Socorro Resource Management Plan and Mimbres Resource Management must be amended so that they would not be violated by the construction of the lines along the BLM Preferred Alternative Route. The proposed RMPAs would include modifications to visual resource management objectives and right-of-way avoidance area management. As noted above, these RMPAs are now subject to a 30-day public protest period which expires July 14, 2013. Although it is likely that protests will be filed, the BLM anticipates issuing a Record of Decision authorizing the project, and approving the RMPAs, in September 2013. Assuming final approval, the project could be operating as soon as 2016. If the project is ultimately completed, it should have a significant impact on renewable energy development throughout the southwestern U.S.