Background

The Mohave Generating Station (Mohave) is a two-unit, coal-fired power plant located in Laughlin, Nevada. Southern California Edison Company (SCE) is the plant operator and owns a 56% undivided interest in Mohave, which entitles SCE to approximately 885 Megawatts (MW). Pursuant to the terms of a 1999 Consent Decree¹ specific environmental controls must be installed at Mohave for it to continue in operation post 2005. SCE filed this application seeking Commission authorization to either make the necessary environmental expenditures, or prepare to close the plant down.

Mohave obtains all of its coal supply from the Black Mesa coal mine, which is located approximately 273 miles east of Mohave in northeast Arizona. The mine is on lands that belong to the Hopi Tribe and Navajo Nation. The coal is transported from the mine to Mohave by way of a coal-slurry pipeline that requires that the coal be pulverized and mixed with water near the mine site to produce the slurry. Once the slurry mixture reaches Mohave, the water is extracted and the coal is dried. The water for the slurry process and for all other water requirements of the mine comes from the N-Aquifer, a well that underlies the land of the Hopi Tribe and Navajo Nation.

Approximately 4,400 acre-feet per year is extracted from the N-Aquifer to slurry the coal. The Hopi Tribe opposes pumping of the N-Aquifer after 2005. Beginning in 2001, SCE and the other Mohave co-owners restarted past efforts to develop an alternative water source to the N-Aquifer for the slurry line. Some time during the pendency of SCE's application, the parties determined that the only potentially viable alternative is the C-Aquifer. In addition to the uncertainty of the water situation, there are also some unanswered questions as to the availability of the coal supply.

D.04-12-016, among other actions, authorized SCE to continue working on resolution of the essential water and coal issues, including the funding of the C-Aquifer hydro-geological and environmental studies. Once the two primary unknown questions concerning the availability of water and coal supplies are ascertained, the Commission will review those costs and determine if it can make a final decision on the future of Mohave as a coal-fired plant.

Numerous parties participated in this proceeding including: The Navajo Nation, Hopi Tribe, Salt River Agricultural Improvement and Power District, the Center for Energy and Economic Development, The Utility Reform Network (TURN), Office of Ratepayer Advocates (ORA), NRDC and Water and Energy Consulting (WEC).

Nine parties protested SCE's application. On October 11, 2002, a combined Prehearing Conference (PHC) and Public Participation Hearing (PPH) was held at the Navajo Chapter House in Tuba City, Arizona. On January 7, 2003, the assigned Commissioner issued a Scoping Memo; evidentiary hearings were held June 14 through July 9, 2004; post hearing concurrent and reply briefs were filed August 9 and August 24, 2004, respectively; the proposed decision (PD) was mailed on October 20, 2004; final oral argument (FOA) was held on November 30, 2004; comments and reply comments to the PD were received; and on December 2, 2004, the Commission issued its decision in the proceeding. No applications for rehearing or petitions for modification were filed. The proceeding is closed.

NRDC actively participated in this proceeding including filing a protest; attending the October 2002 PHC/PPH; submitting testimony; sponsoring expert witnesses/testimony; conducting cross-examination; filing concurrent opening and reply briefs; submitting comments and reply comments to the PD and participating in the FOA. NRDC's primary role in the proceeding was proposing alternatives to Mohave continuing as a coal-burning plant to be studied along with pursuing solutions to the outstanding coal and water issues.