San Juan Generating Station. Source: Wikimedia

Public Service Co. of New Mexico completed the shutdown of two of the four units of its San Juan Generating Station near Farmington, NM.

Operators shut down both coal-fired units a few days earlier than planned because of mechanical problems. Unit 2 was shut down around noon on December 20 and Unit 3 was taken offline a day earlier. The utility says it would have been uneconomical to repair the units because they were scheduled to be shut down later in the week.

The retirement of the two units is part of the Revised State Implementation Plan, which stemmed from an agreement among the New Mexico Environment Department, the U.S. Environmental Protection Agency and the utility. Retiring the units is necessary for the utility to comply with federal visibility regulations under the Clean Air Act. The closure reduces the plant's emissions, including carbon dioxide, as well as its use of coal and water, by around 50 percent.

Crews will now begin cleaning out the units and completing other procedures to permanently retire them from service. The agreement with the EPA mandates that the units be completely out of service by December 31.

Unit 2 came online when the plant opened in 1973 and is the oldest unit at San Juan. Unit 3 began operation in 1979. The shutdown will result in the reduction of energy generation of approximately 836 MW. PNM plans to replace that loss with increased renewable energy, existing nuclear power and natural gas generation.