Emissions cap threatens Wyoming gas E&D

• Where Green River Basin Action is threatened by air rules [42553 bytes]

A number of companies-including Amoco Corp., Texaco Inc., Enron Oil & Gas Co., Mobil Corp., Union Pacific Resources Co., and several smaller independents-have plans to begin or expand production in four major gas fields-Fontenelle, Moxa Arch, Stagecoach Draw and Jonah-in Wyoming's Green River basin.

Southwest Wyoming gas is gathered by pipelines at the Opal hub for delivery primarily to California, as well as to markets in the Midwest.

But the projects were dealt a blow earlier this year when federal regulators determined that total nitrogen oxide emissions from future development within the Bureau of Land Management's Rock Springs District, which includes the gas fields, can't exceed 977 tons/year.

Wellsite and pipeline compressor emissions have been estimated at 5.1 tons of NOx/well/year.

At that rate, the NOx cap would limit the number of additional wells in the area during the next decade or so to less than 200, instead of the potential 3,000 wells operators have envisioned in the four fields.

Industry has appealed the federal decision, as has the state of Wyoming. Meanwhile, the office of Wyoming Gov. Jim Geringer has coordinated a forum of industry, government, tribal, and public interest group representatives to attempt to reach a consensus on air quality issues and industrial development in Southwest Wyoming.

Airshed concerns

The curbs on emissions are being driven by the Wilderness Act and the Clean Air Act's provisions for protecting pristine, or Class I, airsheds.

The largest Class I airshed in the contiguous U.S. is aloft the 428,000-acre Bridger Wilderness in the Bridger-Teton National Forest, about 70 miles north-and frequently downwind-of the proposed Green River basin development.

In an analysis released in May, BLM concluded that the effects on visibility-primarily increased haze-in the wilderness area as a result of the development would be within acceptable levels.

Similarly, BLM said that atmospheric deposition from natural gas development would be minimal and there would be "no significant degradation of water quality" from acid rain that could kill aquatic life in the mountain lakes within the wilderness.

But the U.S. Forest Service did its own modeling of the data in the BLM analysis and concluded that under a worst-case scenario, the development would lead to a deterioration of air quality, particularly visibility, within the wilderness.

Views and deciviews

A key difference between the BLM and the Forest Service interpretations of the data centers on the threshold for acceptable levels of change. The BLM used a threshold value of 1.0 deciview-a 10% change to ambient conditions.

In addition, the BLM analysis tossed out days where relative humidity exceeded 68%, essentially on the grounds that if humidity is that high in the arid basin, cloud cover and precipitation would render visibility impacts moot.

The BLM model concluded that the natural gas projects, when added to existing emissions from the gas processing plants, trona processing facilities, coal-fired power plants, and other industrial operations in the area, could result in a worst-case perceptible change to visibility on 26 days each year within the Bridger Wilderness area.

Under its less-conservative scenario, the BLM model determined there would be no days with a perceptive visibility change.

The Forest Service model used different assumptions about relative humidity and other factors, and then applied a 0.5 deciview limit of acceptable change. The result: a perceptible change in visibility on 153 days under a worst-case scenario and on 18 days under a less-conservative scenario.

To mitigate the effects, the Forest Service, with support from the Environmental Protection Agency, recommended a 977 ton/year cap for NOx emissions from new development on federal lands in the BLM's Rock Springs District.

The BLM said it "could not embrace" the Forest Service analysis, but the former agency adopted the cap anyway, citing the Forest Service concerns and "the mandates of the Clean Air Act and the Wilderness Act to ensure the protection of wilderness resources."

A stab at consensus

Providing it withstands appeals filed by Wyoming and the industry, the NOx cap will stay in effect until a technical analysis shows the cap should be changed.

The most likely place from which such a technical analysis might emerge is the newly formed Southwest Wyoming Technical Air Forum.

The forum has grown out of earlier "kitchen table" meetings fostered by Geringer and which up until early October included only the government agencies involved in managing resources in Southwest Wyoming: BLM, Forest Service, EPA, and Wyoming Department of Environmental Quality.

Managers with those agencies met with industry, tribal officials, and environmental groups in early October to solicit technical and policy representatives to serve on the forum.

The group's goals include agreeing on what monitoring methods to use and what levels of change in air quality are acceptable in the wilderness.

Industry view

Tom Clayson of the Petroleum Association of Wyoming was openly skeptical at the October meeting.

Noting that the EPA and the Forest Service had worked together to impose the emissions cap after BLM had initially found no need for a cap, Clayson wondered if the federal agencies would similarly go their own way after the air forum makes a recommendation.

Regulatory officials at the meeting responded that the group's goal is to achieve consensus and preclude the problem Clayson identified.

However, the group's recommendations will not be legally binding, and if one of the agencies decides to go out on their own, that's a "train wreck," said Dennis Hemmer, director of the Wyoming DEQ.

Air concerns overblown?

Looming over the debate are many questions-if few answers-about the effects on air quality from existing emissions sources, including sources outside Wyoming's boundaries.

Amoco, a key operator in the basin's Moxa Arch project, has already complained that the emissions from future gas development in southwestern Wyoming, even under the worst case scenarios, are insignificant compared to overall NOx emissions in the region.

And if there is in fact degradation of air quality in the wilderness, the 977- ton cap on emissions from natural gas development won't do much to prevent it, the company says.

Amoco may have a point. Southwest Wyoming is already home to two coal-fired power plants, three surface coal mines, six gas processing plants, six trona plants, and 27 oil and gas fields.

An inventory of NOx emissions in Southwest Wyoming compiled for the BLM indicates operators of the region's industries are currently permitted to emit nearly 130,000 tons/ year of NOx.

However, the Wyoming DEQ estimates that perhaps a little more than half that amount is actually being emitted. Thus, the 977-ton cap for gas development represents less than 1% of that already permitted total.

And Utah's Wasatch Front, home of a booming Salt Lake City-area economy, is about 200 miles upwind of the Green River Basin.

The 1993 Utah Air Emission Inventory reported more than 70,000 tons of NOx emissions from the four most heavily populated counties along the front.

Lack of good data

"There is a lack of credible, reliable data documenting air quality degradation, or the source of that degradation, if any, in southwestern Wyoming," said Dan Heilig with the Wyoming Outdoor Council, an environmental group that feels the federal agencies should make more of an effort to protect the wilderness.

But long-time residents in the area swear that the view has deteriorated as the result of industrial activity the last couple decades. The new gas development could be "the straw that broke the camel's back," Heilig said, perhaps leading to irreparable damage to "one of the most significant wilderness resources in the country."

And it is the very lack of scientific consensus that in part is driving the Forest Service's actions, noted Dennis Haddow, an air program manager with the agency's Rocky Mountain Region.

Faced with scientific uncertainty, the Forest Service is legally obliged to err on the side of protecting the resource, Haddow said.

Even if the scientists and the regulatory agencies determine that emissions from other sources pose more of a threat to visibility and aquatic life in mountain lakes in the wilderness than proposed gas projects, that finding alone may not do much to ease the emissions cap.

Often, when the Clean Air Act is enforced, said Haddow, "The guy that's out there getting hammered on the hardest is the new guy on the block."

Copyright 1996 Oil & Gas Journal. All Rights Reserved.