The Pennsylvania Department of Environmental Protection (DEP) has released new data from 2012 that shows emissions from the state's natural gas industry remained largely flat compared to 2011 when less development was happening in the Marcellus Shale.
The DEP's annual report said nitrogen oxides and sulfur dioxide emissions decreased, while emissions of carbon monoxide, particulate matter and volatile organic compounds (VOC) all increased by varying degrees. The industry sources and activities tracked in the report include compressor stations, dehydration units, drilling rigs and devices, such as connectors, flanges, pump lines and valves, among other things.
The agency's latest emissions inventory includes a new category, as 2012 marked the first time that 250 compressor stations handling natural gas from conventional well sites were included.
"There was a significant increase in activity while most emissions categories were flat or had decreased, which is evidence that the industry is controlling more to maintain these trends with an increase in development," said Kathryn Klaber of the Klaber Group, an energy and environmental consulting firm in Pennsylvania.
The data comes from a time before the DEP expanded upon proposed federal standards from the U.S. Environmental Protection Agency (EPA). Last year, the DEP made revisions to its General Permit, or GP-5, that imposed stricter limits on VOCs, nitrogen oxides and carbon emissions from natural-gas fired engines and equipment from compressor stations (see Shale Daily, Feb. 4, 2013).
"It was sort of a win-win regulation because it was good for the environment and it incentivized capital investment," said Klaber, who also sits on the DEP's Air Quality Technical Advisory Committee. "The incentive is there for a company to over-control in order to affect the timeline of getting a permit."
The permit revisions allow a company to demonstrate that it went "above and beyond" the state's standards, making the application process quicker and allowing companies to accelerate their operations, Klaber said.
"It sends a message to the industry that if you take extra steps, you can get a permit faster."
The DEP also finalized new air quality criteria for unconventional operators last year that require them to take more steps to reduce emissions or submit an air quality plan before well site operations can begin (see Shale Daily, Aug. 12, 2013). Combined with the revised permitting standards for natural gas-fired engines and compressor stations, the agency said that these steps could significantly lower emissions in its next report.
"It is important to note that across-the-board emission reductions can be attributed to the steady rise in the production and development of natural gas; the greater use of natural gas; lower allowable emissions limits, installation of control technology and the deactivation of certain sources," said DEP Secretary Chris Abruzzo.
The EPA said in a 529-page report in February that total methane emissions from natural gas systems nationwide decreased by 2.4% from 1990 to 2012, while greenhouse gas emissions also declined during the same period by 3.3% (see Shale Daily, Feb. 25). Although it's been challenged by studies and groups such as the Environmental Defense Fund (see Shale Daily, Feb. 14), national reductions in the EPA's report were credited to a large decrease in emissions from natural gas production and distribution.
Klaber said many companies were already preparing to meet federal standards and added that the anticipated increase in Pennsylvania's natural gas development might not necessarily reduce future emissions.
"You have to look at each emission compound separately. Not all facets of the regulations affect each regulated pollutant in the same way," she said. "I think emissions are correlated with the amount of activity. Emissions will be affected by how many new wells and compressor stations are put into place. I do believe that we will continue to see more controls because of the general permit revisions and other factors."
The DEP's 2012 report relied on data from 56 Marcellus Shale operators covering 8,800 natural gas wells and 70 operators of 400 compressor stations, which received gas from both the Marcellus Shale and shallower formations.
Nitrogen oxides decreased by 1.09% to 16,361 tons and sulfur dioxide decreased by 17% to 101 tons. Carbon monoxide, however, increased by 7.27% to 7,350 tons; particulate matter increased by 9% to 548 tons and VOCs increased 42% to 4,024 tons.