HARRISBURG– The Department of Environmental Protection (DEP) has released annual emissions data for the natural gas drilling industry. The inventory represents 2012 emissions levels from Marcellus Shale natural gas production and processing operations as well as compressor stations that receive gas from traditional oil and gas well sites.
“The natural gas emissions inventory was created to collect and assess air quality impacts from these sources,” DEP Secretary Chris Abruzzo said. “This vital information assists DEP in its efforts to improve Pennsylvania’s air quality.”
In addition to the emissions inventory, DEP has implemented new measures for controlling and reducing emissions from natural gas sites. In 2013, DEP made revisions to the general permit, GP-5, that regulates emissions from natural gas-fired engines and equipment at compressor stations. The changes will significantly lower allowable emissions for compressor stations.
DEP also finalized new air quality criteria for Marcellus Shale gas well owners and operators. These criteria require actions to be taken which are more stringent than the EPA’s standards for new emission sources and result in emission levels of minor significance. If an owner or operator is unwilling to or cannot meet these criteria, they must seek an air quality plan approval for construction of the well site from DEP.
The sources and activities of natural gas operations that DEP identified as part of the inventory include compressor stations; dehydration units; drill rigs; fugitives, such as connectors, flanges, pump lines, pump seals and valves; heaters; pneumatic controllers and pumps; stationary engines; tanks, pressurized vessels and impoundments; venting and blow down systems; well heads and well completions.
For the 2012 inventory, data reported to DEP came from 56 Marcellus Shale operators covering 8,800 natural gas wells and 70 operators of 400 compressor stations, which received gas from Marcellus Shale and traditional oil and gas well sites. New to this round of reporting were 250 additional compressor stations that process gas from traditional well sites. These compressor stations were not required to report in 2011.
The totals reported for the 2012 natural gas emissions inventory are:
- 16,361 tons of nitrogen oxides, a 1.09 percent decrease from 2011;
- 101 tons of sulfur dioxide, a 17.21 percent decrease from 2011;
- 7,350 tons of carbon monoxide, a 7.27 percent increase from 2011;
- 548 tons of particulate matter (PM)2.5, a 8.51 percent increase from 2011;
- 600 tons of PM10; a 3.99 percent increase from 2011; and
- 4,024 tons of volatile organic compounds, a 42.70 percent increase from 2011.
Significantly, since 2008, when unconventional drilling across the state began quickly increasing, cumulative air contaminant emissions across the state have continued to decline. In particular, sulfur dioxide emissions from electric generating units (EGU) have been reduced by approximately 73 percent. The emissions of nitrogen oxides and particulate matter have also been reduced by approximately 23 percent and 46 percent, respectively, from this sector.
“It is important to note that across-the-board emission reductions in emissions 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 Abruzzo.
These reductions represent between $14 billion and $37 billion of annual public health benefit, based on U.S. Environmental Protection Agency (EPA) methodologies.
The U.S. EPA requires Pennsylvania to submit a comprehensive air emissions inventory every three years which includes emissions data from sources such as refineries, manufacturing plants, power plants, dry cleaners and cars, trucks and other vehicles. The last comprehensive inventory was submitted in December 2012 for calendar year 2011. The next comprehensive submission will be due on Dec. 31, 2015, for calendar year 2014.
In addition to the EPA submission, DEP regulations and Act 13 of 2012 directs owners and operators of unconventional and conventional natural gas sources to report their emissions annually for the previous year to DEP by March 1 of each year.
To view the emissions inventory, visit www.dep.state.pa.us and click “Air” and then “Bureau of Air Quality.”