The 1GW line would cross parts of Arizona and New Mexico. Source: Wikipedia

The Western Area Power Administration and Southline Transmission, L.L.C. agreed to upgrade existing electrical infrastructure and build new transmission lines to provide about 1,000 megawatts of transmission capacity along a 360-mile path between southern New Mexico and Arizona.

The project will interconnect with 14 existing substations in an effort to improve reliability, relieve transmission congestion, meet increased energy demand, and facilitate construction of new generation resources.

The project involves two segments:

• Constructing about 240 miles of new double-circuit, 345-kilovolt line south of Las Cruces, New Mexico, to south of Willcox, Ariz.
• Upgrading about 120 miles of existing WAPA transmission line from single-circuit 115 kV to double-circuit, 230 kV between Willcox, Arizona, and a substation northwest of Tucson.

The line will cross federal lands managed by the Bureau of Land Management and other agencies. It will also cross state and private lands.

Construction is anticipated to begin in late 2018 with transmission operations phased into service beginning in 2020.

WAPA's share of transmission capacity will be incorporated under WAPA's Parker-Davis Project. Southline's transmission capacity was offered to potential transmission customers in a Federal Energy Regulatory Commission-approved open solicitation process in 2016.

Other agreements will be negotiated over the coming months, including construction, operations and maintenance, ownership and lease agreements.

Project development activities began in 2012 and include:

• Completing an Environmental Impact Statement and final federal approvals in April 2016
• Obtaining state siting approval from Arizona in February 2017
• Obtaining state siting approval from New Mexico in August 2017
• Soliciting transmission capacity requests on Southline's share of the future line through an FERC-approved open solicitation process

Southline Transmission, L.L.C., a unit of Hunt Power, is the project sponsor. Hunt Power develops and invests in electric and gas opportunities, and is part of a larger privately-owned group of companies managed by the Ray L. Hunt family, who engages in oil and gas exploration, refining, power, real estate, ranching and private equity investments.