NMED data details industry-reported excess emissions, including why they occurred

Hannah Grover
Farmington Daily Times
A flare stack at the San Juan Processing Plant is pictured, Friday, Feb. 1, 2019, in Kirtland.

FARMINGTON — Industries and utilities emitted more emissions than permitted — approximately 50 times in San Juan County and nearby areas within the last 12 months — according to data released by the New Mexico Environment Department earlier this week.

The data included nearly 1,800 reports of excess emissions from all parts of the state. These excess emissions do not necessarily constitute violations, however NMED states they are an opportunity for reductions.

This data is based on industry accounts and includes volatile organic compounds and nitrogen oxides, which interact with sunlight to form ozone, or smog. Seven New Mexico counties, including San Juan County, are currently pushing the federal threshold for ozone.

There are many reasons that excess emissions occur, as seen in the data. Sometimes equipment fails. Other times, conditions outside of the company's control lead to excess emissions. For example, a car crash cut off power to a compressor station earlier this year.

Here’s a look at some of the reasons industries and utilities gave for excess emissions. A full list of excess emissions is available on the NMED website.

San Juan River Gas Plant's excess emissions reported over several years

In most of the reported incidents, the problem was quickly identified and remedied within a day or two. However, CCI San Juan reported several years of excess emissions from the San Juan River Gas Plant.

The plant began emitting excess emissions in October 2016. Between then and Nov. 30, 2018, the San Juan Gas Plant emitted more than 17,000 excess pounds of carbon monoxide, nearly 350 pounds of nitrogen dioxide, almost 1.6 million pounds of sulfur dioxide and more than 11,000 pounds of sulfur dioxide.

These excess emissions occurred because of changes in the plant’s inlet gas concentrations as well as unusual wear of compression valves and other parts. This resulted in the flaring from the gas plant exceeding the hourly emissions limits the company’s permits allow, according to information CCI San Juan provided NMED.

Mill configuration leads to excess nitrogen dioxide emissions at SJGS

The data also includes San Juan Generating Station. On Jan. 3, there was a belt failure and breaker shortage at the unit 4 coal reclaim. Public Service Company of New Mexico took the unit offline and board operators scrambled to adjust the mill configuration and to continue to burn the remaining coal that was in the unit, according to the report PNM submitted following the incident. Because of the abnormal mill configuration, the coal combustion was also irregular. This resulted 0.04 pounds of excess nitrogen dioxide emissions for approximately three hours.

Two of the four units at the San Juan Generating Station have already closed as part of an agreement with the U.S. Environmental Protection Agency to cut emissions at the power plant.

Animas Power Plant struggles on startup and shut down

Throughout the last year, the Animas Power Plant has struggled with excess carbon monoxide emissions on multiple occasions. The City of Farmington rarely uses the Animas Power Plant because of its age and condition. It plans to retire the power plant.

However, the Animas Power Plant is used in emergencies, and when there is not enough electricity from other sources like the San Juan Generating Station, Bluffview Power Plant or Navajo Dam.

The Animas Power Plant is pictured, Wednesday, Feb. 27, 2019, in Farmington.

There were nine reports of excess emissions from the Animas Power Plant in the last 12 months. All of these incidents occurred during shutdown or startup of the plant, which does not have permitted startup, shutdown and maintenance emissions.

The largest excess emissions report from the Animas Power Plant came in November 2018 when more than 19 pounds of excess carbon monoxide was emitted over the course of an hour. This happened when the Farmington Electric Utility System had to start up the plant due to the unplanned shutdown of a neighboring power plant. The city needed more electricity to stabilize the grid and the excess emissions occurred while the plant was being started.

Contractor finds excess carbon monoxide at Chaco Gas Plant

Enterprise Field Services hired a third-party emissions testing company to look at emissions from the Chaco Gas Plant. This contractor found one of the vent stacks was emitting excess carbon monoxide on July 23. Enterprise Field Services reported 26.4 pounds of excess carbon monoxide over 22 hours. That was the sole report of excess emissions from the Chaco Gas Plant.

Car crash, cold weather impact Blanco Compressor C&D Station

The majority of reports Enterprise filed came from the Blanco Compressor C&D Station and many of the incidents were caused by valves or scrubbers hanging open, which allowed gas to flow at higher than normal rates through process flares.

However, when a car crashed into a Farmington Electric Utility System power pole on July 21, the power failure caused Blanco’s turbines to go down. This resulted in 3,697 pounds of excess volatile organic compounds being emitted over the course of an hour and 15 minutes as Farmington worked to restore power.

A transmission pole was damaged during a car crash July 21, 2019, in Farmington.

Cold weather also contributed to excess emission in January at the Blanco compressor station. For example, the wind chill temperature at the Blanco station on Jan. 30 was -20 degrees Fahrenheit overnight. The cold temperature, which resulted in less gas on the system, meant the Harvest Midstream Low Pressure Unit went down. That led to more gas than normal flowing to the flare, resulting in 10.9 pounds of excess volatile organic compound emissions over the course of an hour.  

Hannah Grover covers government for The Daily Times. She can be reached at 505-564-4652 or via email at hgrover@daily-times.com.

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