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Water Management:
San Juan Generating Station

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  • San Juan Generating Station uses an average of 22,000 of water acre-feet per year.
  • San Juan has rights to 24,200 acre-feet per year — 16,200 acre-feet from the Navajo Dam reservoir through a Bureau of Reclamation contract and 8,000 acre-feet in native stream flow from the San Juan River through a contract with BHP.
  • Water is used at San Juan for cooling systems and cleaning of equipment and facilities. The plant has cooling towers that condense the steam used in the turbine back into water so it can be reused. Through a series of complex processes, water is reused, at least 10 times and as many as 50 to 100 times before it evaporates.
  • Unit 3 at San Juan has a "hybrid" cooling tower — one that can run in both wet and dry modes. Unfortunately, this unit has not performed as well as the wet cooling tower units. Engineering estimates indicate that converting the plant to dry cooling could add at least 10 percent to the cost of electricity production because of lower energy efficiency and increased construction and maintenance costs. Because of the "energy penalty" thus imposed, the amount of emissions per megawatt produced will also increase with the use of dry cooling.
  • San Juan is a "zero discharge" facility, meaning no wastewater is discharged to either the San Juan River or underground water supplies.


PNM's efforts to secure short-term supplemental water supply and the San Juan Basin shortage sharing recommendations:

  • Due to drought conditions in the Four Corners area and at the suggestion of the state engineer and the Bureau of Reclamation, PNM and 12 other parties in the Four Corners region were encouraged to develop a voluntary shared shortage water plan based on reasonable use to address anticipated shortages this year.
  • Starting in the fall of 2002, the Navajo Nation, the Jicarilla Apache Nation and the other entities including PNM, Arizona Public Service Co., owner and operator of the Four Corners Power Plant, and BHP Billiton, owner and operator of the Navajo, San Juan and La Plata mines, began negotiations on recommendations to address the potential summer water shortage and resulting usage issues.
  • Principles and recommendations were developed that all 13 parties agreed upon. These recommendations were finalized in May 2003 and were accepted by the state engineer and the Bureau of Reclamation.
  • This shortage sharing arrangement is an unprecedented example of tribal, governmental, agricultural and industrial water users in the Four Corners region working together to establish water priorities and address shortage issues without litigation and prior to a more serious situation occurring.
  • In connection with the shortage sharing arrangement, PNM also entered into a contract to purchase water from the Jicarilla Apache Nation for use at San Juan. This contract has received final approval by the Bureau of Reclamation and the U.S. Fish and Wildlife Service. The one-year contract, with two one-year renewal clauses, will allow San Juan Generating Station access to an additional 8,300 acre-feet of Navajo Reservoir water during shortage time periods.
  • PNM, Arizona Public Service and the mines are currently taking shortages based on recent drought calculations. PNM has paid the Jicarilla Apache Nation $80,000 for the first 10 percent of the allocation.