A proposed power-line system to deliver renewable energy across the Southwest could disturb habitat for sensitive species, harm more than 300 cultural sites, damage scenic views and increase fire risk while it's being built, a new federal environmental report says.
But the Bureau of Land Management report also says that many of these impacts could be eased or otherwise mitigated by careful planning.
The agency's draft SunZia environmental impact statement estimates that its preferred, 530-mile-long route, containing two 500KV power lines, could generate about 2,500 to 3,000 construction jobs lasting two to three years in Arizona and New Mexico. It would also add 3,000 to 4,500 megawatts of power, enough to serve between about 750,000 and 1.125 million homes.
But it's also stirring up controversy among rural Southern Arizona residents, particularly those in the San Pedro River valley east of Tucson.
This route would snake across high and low deserts, grasslands, riparian areas, conifer forests, chaparral and other natural habitats as it delivers power from as yet unbuilt wind and solar energy facilities in this region to customers in four states.
The transmission towers would stand about 135 feet high, as tall or taller than a 10-story building, with the lines about 110 feet high.
Such systems typically cost $1 million to $2 million a mile, totalling between $530 million and $1.06 billion.
The system's purpose is to improve the climate for production of renewable energy - which BLM and many experts say is now limited in this region by the lack of transmission line capacity.
SunZia LLC hopes to start construction in early 2014 and finish in two years.
The lines would start at a substation in rural Lincoln County, N.M., near the town of Corona, and finish at a substation in rural Pinal County, about eight miles north of Eloy and 55 miles southeast of Phoenix.
In between, they would slice through seven New Mexico counties and four Arizona counties - Cochise, Graham, Pima and Pinal, including a Pima County-managed open space parcel in the San Pedro River Valley northeast of Tucson.
SunZia LLC would need about 50 permits, including one from the Arizona Corporation Commission - which just last week wrapped up a bruising controversy by approving a power line for the Rosemont Mine southeast of Tucson.
The SunZia line faces strong opposition from rural residents in the Cascabel, Winkelman and Redington Pass areas.
It's supported by some economic development groups, chambers of commerce and construction workers.
Opponent Daniel Baker of Cascabel is concerned about the prospect of thousands of birds dying in collisions with power lines and transformers, given the San Pedro's status as a globally important migratory bird flyway. The roads needed to build and serve the power lines will trigger severe erosion that will silt up rivers and streams and endanger native fish, said Baker, who lives about 30 miles from Benson near the river's floodplain and is secretary of the Cascabel Working Group.
But the project could bring economic benefits to Cochise County. A proposed solar power plant south of Benson and a wind energy project in the Bowie area have been shelved because there's no line to carry their electricity, said George Scott, director of the non-profit Southeastern Arizona Economic Development Group in Benson.
"Folks trying to do projects in Southern Arizona are looking forward to that SunZia line," Scott said.
But on Tuesday, U.S. Rep. Raúl Grijalva also expressed concern about the impact to rural communities from the power lines along with up to eight towers per mile, and said it's critical that BLM reach out to residents along the route before making a decision.
"We have to protect the resources of the San Pedro River watershed and keep in mind the communities that call this unique place home," Grijalva said. "We need, and the public demands, a final route that has the fewest negative impacts to archaeological resources, migratory birds and rural communities."
Yet for now, this is a project without specific power suppliers or customers.
There are "tremendous" renewable energy resources in the two Southwestern states, and as SunZia progresses, the more likely it will be that the sun and wind energy will get developed, said Ian Calkins, a spokesman for the SunZia Southwest Transmission Project.
As for customers, SunZia has had conversations with them, but can't give any details right now, said Calkins, adding, "We're really focused on the permitting side right now. As we get down the road, we will be announcing customers."
Customers must be secured before construction begins, he said. He also said SunZia can't deny non-renewable energy generators access to the lines, although he said he's not aware of any such sources now.
For Pima County officials, SunZia could be a major concern because the lines would cut through the heart of 34,000 acres of state and federal leased grazing land that's part of the A7 ranch, an open-space preserve that also includes 6,800 county-owned acres. Officials are worried about the power-line route opening up a path for off-road vehicles and non-native species into the area, said Diana Durazo, a staff assistant to county Administrator Chuck Huckelberry.
"But we're just looking at Pima County right now," Durazo said. "What does it mean as a whole when you look at the entire corridor along the San Pedro?"
SunZia LLC is a corporate entity consisting of several sponsors. They include Salt River Project; Tucson Electric Power; Shell Wind Energy; Southwestern Power Group, a Phoenix-based developer of power generation and transmission project developer that did the Gila Bend Power Station, a natural gas generating facility; and Tristate Generation, a wholesale electricity supplier operating in three Western states and Nebraska.
The Bureau of Land Management says its preferred SunZia route would or could:
• Disturb about 2,960 acres.
• Increase the risk of collisions of migratory sandhill cranes with the power line.
• Disturb roosts and remove food plants for the endangered lesser long-nosed bat.
• Kill and/or destroy habitat for the Tucson shovel-nosed snake and the Sonoran Desert tortoise, both candidates for federal protection.
• Increase fire risks, particularly during construction, although the risk "can't be quantified." Once in operation, the power lines could restrict authorities' ability to conduct prescribed burns nearby and pose hazards to firefighting crews.
• Damage more than 300 cultural sites - although the damage can be eased if not eliminated by better planning.
• Create at least moderate visual impacts to nearly half the portion of the route through Southeastern Arizona.
Mitigation measures planned for the project, filling 10 pages of the new BLM report, include:
• Restricting all vehicle movement outside the power-line right of way to designated access roads or public roads.
• Existing access roads would be used as much as feasible to limit disturbance.
• Existing access roads wouldn't be widened or upgraded except for repairs to make them passable, in areas with sensitive soils and vegetation and archaeological sites.
• No new roads would be bladed at perennial streams, designated recreational trails and irrigation channels.
• A detailed reclamation plan would be developed for areas impacted by construction.
• Tower designs would be modified to minimize ground disturbance, visual contrasts and conflicts with birds.
• Power-line structures would be placed at the maximum distance feasible from highway, canyon and trail crossings to minimize visual impacts.
Contact reporter Tony Davis at email@example.com or 806-7746. Follow Davis on Twitter at tonydavis987.