New Mexico Power Plants Retrofitted with Emission Controls

The updates to the plants will seek to reduce pollutants like nitrogen oxides, sulfur dioxides and particulate matter from the atmosphere.

by James Fenton, The Daily Times, Farmington, N.M. / November 2, 2015
The San Juan Generating Station, New Mexico flickr/WildEarth Guardians

(TNS) -- Both Farmington-area power plants have begun installing pollution controls to comply with federal regulations intended to reduce atmospheric haze.

The multi-million-dollar retrofitting projects underway at both coal-fired power plants is to be completed by 2018. The plants — San Juan Generating Station and Four Corners Power Plant — are located 20 miles west of Farmington.

This summer, the Environmental Protection Agency finalized additional portions of the July 1999 regional haze rule, which requires emission controls known as "best available retrofit technology," or BART, be added to industrial facilities that emit air pollutants reducing visibility by causing or contributing to regional haze.

The retrofitting work aims to reduce emissions, especially of pollutants like nitrogen oxides, sulfur dioxides and particulate matter, which impact visibility.

The federal Clean Air Act set the goal of returning national parks and wilderness areas to “natural visibility levels” by 2064, according to an EPA press release.

The pollution controls will also help the state comply with the EPA’s Clean Power Plan, which aims to reduce carbon pollution from power plants to address climate change.

Power plants such as Four Corners Power Plant and San Juan Generating Station are the largest industrial sources of carbon dioxide, a potent greenhouse gas.

Four Corners Power Plant, Fruitland

The plant, owned and operated by majority owner Arizona Public Service Company, or APS, shut down its three older, less efficient generating units in December 2013 as part of a plan to meet federal haze rules at a price that APS could afford. The three units, originally placed into service in 1963 and 1964, would have been too expensive to retrofit with pollution controls. They are expected to be demolished and removed from the plant by 2017.

Retiring those units, which produced a combined 560 megawatts of electricity, reduces the plant's emissions, including nitrogen oxide, by 36 percent, sulfur dioxide by 24 percent, carbon dioxide by 30 percent and particulate matter by 43 percent. The closure also decreases the plant's water use by 6,000 feet per year, according to company documents.

Sulfur dioxide and nitrogen oxide, common pollutants emitted from power plants, have ill effects on human health, including severe respiratory and cardiovascular impacts and premature death. The two are significant contributors to acid rain, smog and haze, according to an EPA press release.

This summer, a record of decision from the U.S. Department of the Interior and a 25-year lease extension breathed new life into the aging plant, triggering a commitment by APS for the millions of dollars necessary to complete the pollution control project at the plant. The lease gives the coal-fired plant the ability to operate until 2041.

The remaining two units, Units No. 4 and No. 5, which are two separate flues housed together in one common stack, will be retrofitted with pollution controls starting this month.

The project, which began several years ago, involves the installation of pollution controls called selective catalytic reduction technology, or SCRs.. The technology and installation will cost approximately $635 million and is expected to be operational by July 2018. The work will require two 95-day outages at the plant. Those outages are slated to occur in fall 2017 and spring 2018, according to David Hansen, APS vice president of fossil fuel generation.

"The technology requires that you inject (liquid) ammonia into the flue gas stream and with the help of a catalyst, it reacts with the flue gas and extracts a majority of the nitrogen oxides from the plant emissions," Hansen said.

The nitrogen oxide is converted to nitrogen, oxygen and water vapor.

“We believe at the end of that process, including the shutdown of Units 1, 2 and 3, the total (nitrogen oxide) emissions for the site, in comparison with what it was several years ago, will be reduced by a total of about 86 percent,” Hansen said.

AEcom, the engineering and construction company that will perform much of the retrofit work, recently completed a similar SCR project at Detroit Edison-owned Saint Clair Power Plant in Michigan.

Brent Gifford, APS major projects manager, said Four Corners Power Plant's units were built by the same manufacturer in the same decade as those at Saint Clair.

Steven Gotfried, APS spokesman, said that the retrofit project will benefit the construction sector.

So far, the plant has 12 people working on the project, but at the height of construction 750 people, working in temporary positions, will be added, Gotfried said.

San Juan Generating Station, Waterflow

The San Juan Generating Station, which is owned and operated by majority owner Public Service Company of New Mexico, or PNM, is enmeshed in a case before state regulators over whether the utility’s compromise plan to shutdown two of the plant’s units and retrofit two others is acceptable.

PNM's plan includes the installation of nitrogen oxide emissions reduction technology on Units No. 1 and No. 4 by the end of January and retiring Units No. 2 and No. 3 by the end of 2017.

The plan was developed as a compromise after plant officials said meeting federal haze regulations under the federal Clean Air Act at the plant would be too expensive and result in the utility closing the station.

Both units at the plant will receive selective non-catalytic reduction, or SNCR, which reduces nitrogen oxide emissions.

Plant Manager Tom Fallgren said the plant will add about 800 temporary workers during the roughly two-month overhaul of Unit No. 4, the same amount of jobs added during the outage work on Unit No. 1 in February and March. Unit No. 4 work was scheduled to begin after the peak season of summer was over on Oct. 3, he said.

The majority of those jobs will be filled by boiler makers who do duct work and tube welding. Other required specialties include electricians, general laborers, carpenters who build scaffolding and iron workers who build structural steel, he said.

Unlike Four Corners Power Plant, the generating station's retrofitting work using SNCRs, will be less apparent to the eye after the work is completed.

Instead of adding a structure to house the catalyst for an SCR project, the SNCR retorift at the generating station will add about a dozen injection ports — designed to deliver urea inside the unit's furnace — toward the top of the boiler as well as three induced draft fans, Fallgren said.

APS' ability to add SCR pollution control technology at the Four Corners Power Plant was possible because room was available, he said.

"Four Corners (Power Plant) has more real estate, but here we have limited real estate, plus there's the cost of an SCR for us," Fallgren said. "It's pretty well proven technology, and we have good confidence that we will have a great product at the end of this process."

Jodi McGinnis, PNM spokeswoman, said the project cost is a little more than $78 million.

Maureen Gannon, executive director of environment and safety at PNM, said the work will bring the coal-fired power plant into compliance with state and federal regulations.

“We're moving forward to comply with the regional haze rules,” Gannon said. “What's been provided to the PRC is the right plan, the most cost-effective plan that will reduce the plant's carbon footprint, which will be a huge step for the state.”

George San Miguel, natural resource manager at Mesa Verde National Park, said the pollution controls are welcome news to the national park system.

San Miguel, who has been at Mesa Verde for 17 years, said that visibility is a perennial problem — one that park visitors report degrades their experience of the park — but the pollution controls represent a logical step forward.

San Miguel said that Mesa Verde park staff took pictures three times a day for many years to document visibility conditions at the park, and the images are still a valid representation of atmospheric conditions today. Several years ago the park switched to a quantitative filter system the park uses to add data to the park system website.

San Miguel said that cold air inversion events during colder months trap pollutants, concentrating them at ground level. However, haze during warmer months of the year can diminish visibility even more.

"Often, especially in the mornings, at Mesa Verde, we are high above the inversion and can see clearly over the top of it to the Chuska Mountains in Arizona in the distant background," San Miguel said in an email. "Summer haze is very different as it rises higher in the atmosphere and surrounds us, obscuring visibility in all directions."

On clear days, San Miguel said he can see Shiprock from the park as a sharply definable landmark, but more often it appears as a faint blurred outline and sometimes it is entirely obscured. He said the national parks are supportive of power plants being retrofitted, but other sources — cars, trucks, bulldozers, fires, to name a few — of air pollution should be considered.

"We have been supportive of the efforts to retrofit the power plants in Northwest New Mexico, and we believe that in the future it will pay dividends," San Miguel said. "(The EPA's 2064 deadline) does seem like a pretty difficult bar to reach when you consider how much pollution this area is getting now to get to natural background levels, if we really take a look at our industrial way of life ... Whether we’ll be done in 50 years, we won’t be around to see them. Our hope is that we move in that direction. Everyone has a stake in this."

©2015 The Daily Times (Farmington, N.M.) Distributed by Tribune Content Agency, LLC.