BLM refines preferred route in final EIS for SunZia project

The U.S. Bureau of Land Management (BLM) has refined its preferred route for the proposed SunZia Southwest transmission project, with a route detailed in the final environmental impact statement (EIS) that is some 15 miles shorter than the route in the draft EIS issued more than a year ago.

The information is contained in the Notice of Availability (NoA), scheduled to be published in the Federal Register on June 14 and providing official notice that the final EIS and proposed resource management plan (RMP) amendments for the project have been published.

The lengths of the route alternatives the BLM considered for both the draft and final EIS documents ranged from about 460 to 530 miles. The BLM’s preferred alternative route in the final EIS, which includes some modifications to the route in the draft EIS, is approximately 515 miles in length compared to a 530 mile route in the draft document.

BLM estimates that about 185 miles, or 36%, of the right-of-way for the preferred route is located on federal lands administered by four BLM field offices in New Mexico, as well as federal lands administered by two BLM field offices in Arizona. The BLM preferred route would cross about 135 miles of federal lands in New Mexico and 50 miles of federal lands in Arizona.

About 273 miles of the BLM preferred alternative route would fall within designated utility corridors.

The route was selected after considering issues and impacts identified during the project’s scoping period, including effects on wildlife habitat, migratory birds, bighorn sheep, cultural resources and archeological sites, Native American traditional properties, and viewsheds, among other factors.

The final EIS includes a description of the BLM’s preferred route for the project as well as discussions of route alternatives that were considered and evaluated, but ultimately rejected.

Project developers characterized the issuance of the final EIS as the clearing of a major hurdle.

“This sends a very strong message to the financial community that the project is strong, that it makes good economic sense, and that it is moving forward,” a SunZia spokesperson told TransmissionHub June 13.

Eastern portion alignment

The BLM preferred alternative for the eastern portion of the project would stretch approximately 230 miles from the proposed SunZia East substation to the proposed Midpoint substation northeast of Deming, N.M.

From the SunZia East substation, the preferred route proceeds northwest into Torrance County, N.M., about four miles north of the Gran Quivira Unit of Salinas Pueblo Missions National Monument, and then enters Socorro County, east of the Sevilleta National Wildlife Refuge. The route crosses the Rio Grande River north of Socorro, then turns south along an existing transmission line path into Sierra County, continuing south to the proposed Midpoint substation site.

That portion of the route parallels approximately 141 miles of existing or designated utility right-of-way, and crosses approximately 108 miles of public land administered by the BLM, according to the agency.

Other routes were considered and eliminated from detailed study in the draft EIS/RMP amendments, including an alignment that would have crossed the Fort Bliss Army Base. That specific group of route alternatives was eliminated from consideration because base leadership indicated that overhead transmission lines “would have substantial impacts to military operations and would not be compatible with its mission,” according to the NoA.

Western portion alignment

The BLM preferred alternative for the first segment of the western portion of the project is approximately 124 miles long. It extends west from the proposed Midpoint substation site, then crosses a 115-kV transmission line and U.S. Route 180 about 7.5 miles north of Deming before it proceeds southwesterly, then turns northwest to parallel a 345-kV transmission line and pipeline adjacent to the Lordsburg substation site northeast of Lordsburg, N.M.

The preferred route then heads west, crossing from Hidalgo County, N.M., into Greenlee County, Ariz. The route continues west into Graham County and south of the Hot Well Dunes Recreation Area, then continues through the San Simon Valley to the proposed Willow-500-kV substation site northeast of Willcox, Ariz.

From the Willow substation, the second segment of the western portion of the project extends an additional 161 miles and follows an existing 345-kV transmission line corridor southwest from the substation. It crosses the San Pedro River about 12 miles north of Benson, Ariz. The route then continues northwesterly, crossing the northeast corner of Pima County, then follows a westerly path through Pinal County, north of Oracle toward the Tortolita substation northwest of Tucson.

The first section of the western portion of the route parallels about 42 miles of existing or designated utility corridors, and crosses approximately 62 miles of public land administered by the BLM. The second section of the western portion of the route parallels about 90 miles of existing or designated utility corridors, including approximately 72 miles of existing transmission lines, and crosses about 15 miles of public land administered by the BLM.

RMP amendments

Where the proposed project does not conform to BLM RMPs, the final EIS proposes land use plan amendments to bring the project into conformance. The BLM proposes amending existing RMP visual resource management (VRM) decisions and right-of-way avoidance areas in the Socorro, N.M., RMP dated 2010, and the Mimbres, N.M., RMP dated 1993.

The BLM received more than 900 submittals during the comment period for the draft EIS/RMP amendments, which contained more than 2,000 unique comments. The final EIS/proposed RMP amendments include responses to all substantive comments and revisions to the EIS, according to the BLM.

Changes that stemmed from the comments included modifying a portion of the route that passed near the White Sands Missile Range to increase the distance between the proposed transmission lines and military operations at the range. Other changes addressed sensitive environmental resources near the Lordsburg Playa and the Peloncillo Mountains Wilderness. Additional considerations for National Scenic and Historic Trails were also included in the final EIS/proposed RMP amendments.

Project specs

The proposed project would include two new, single circuit 500-kV transmission lines located adjacent to one another. One of the lines would be constructed and operated as an AC line, and SunZia may construct and operate one of the proposed transmission lines as either AC or DC, according to BLM’s notice.

The requested ROW width would be about 400 feet, to accommodate a separation of 200 feet between the two lines, but could be up to 1,000 feet wide in areas where terrain poses engineering or construction constraints, BLM said in the final EIS.

The purpose of the proposed SunZia Southwest transmission project is to transport electricity generated by power generation resources, including renewable resources, to western power markets and load centers. The project would enable the development of renewable energy resources including wind, solar, and geothermal generation by creating access to the interstate power grid in the southwest, according to the BLM.

Publication of the NoA in the Federal Register starts a 30-day period during which protests to the RMP amendments can be submitted. In addition, after a final EIS is published, a minimum 30-day waiting period is required under NEPA before a record of decision (ROD) can be issued. The ROD will notify the public of the decision made on the proposed action and will include the reasons for the decision.

The final EIS/proposed RMP amendments have already been sent to affected federal, state, tribal and local government agencies, public libraries in the project area, and to interested parties that previously requested a copy, according to the BLM.

Once the ROD is issued, the developer plans to move forward with the state permitting efforts in both New Mexico and Arizona, which the SunZia spokesperson said could extend into 2014. Additional next steps will include finalizing project financing.

SunZia developers have been reluctant to estimate a final price tag for the project, although they acknowledged previously that projects of the size and scale of SunZia typically average in the range of between $1m and $2m a mile.

The project is scheduled to enter service in 2016, according to TransmissionHub data.