Dive Brief:

• The Arizona Corporation Commission is expected to decide Wednesday whether the builders of the SunZia Southwest Transmission Project, proposed to deliver high-value southwestern wind and solar power to cities in California and Arizona, can be required to reserve a portion of the line’s 3,000 MW capacity for renewable energy.
• The Wilderness Society (TWS) and other environmentalists want half the carrying capacity of one of the two 500-kilovolt alternating current (AC) lines reserved for electricity generated by wind and solar and other considerations in return for agreeing on SunZia’s route through Arizona’s San Pedro River Valley.
• SunZia’s developers say such a restriction on the 515 mile, $2 billion project violates federal law forbidding power lines from "undue discrimination" against independent power producers. The environmental groups argue Arizona’s regulators can impose the restriction.

Dive Insight:

The transmission project is being built by a consortium that includes Southwestern Power Group II, a natural gas plant developer, the Tri-State Generation and Transmission Association, Shell Wind Energy, and two Arizona utilities, Salt River Project and Tucson Electric Power.

TWS and other environmentalists accept the need for new transmission but say the route through the San Pedro River Valley chosen by the Bureau of Land Management (BLM) fails to balance the need to deliver renewables and “unacceptable impacts” to the environment. They argue that without restrictions on the line’s carrying capacity it will end up delivering natural gas-generated electricity from a planned Southwestern Power Group II power plant.

SunZia has a letter of intent from SunEdison, in which the renewables developer commits to using about half the line’s carrying capacity to deliver wind energy-generated electricity from its planned Gallo Wind Project in New Mexico to off-takers in Arizona and California. The wind project is scheduled to be online by 2021.

At an Arizona Corporation Commission hearing on Tuesday, critics of the line criticized the Obama administration for pushing fast track approval of the line through the remote lower San Pedro valley, where little development exists today. The head of the state's consumer advocate agency endorsed the project, telling regulators it would allow utilities to purchase cheaper power on interstate markets and help ensure electric reliability.

The Arizona Daily Star reports the commission is expected to rule on the SunZia line Wednesday.