On Thursday the Department of Environmental Protection reported 2015 methane emissions from unconventional natural gas operations increased slightly-- from 107,735 to 112,128 tons- 4 percent-- with more facilities and an increase in natural gas production from 4.1 to 4.6 trillion cubic feet between 2014 and 2015.
Air emissions from other pollutants including nitrogen oxides (NOx), sulfur dioxide (SOx) and particulate matter (PM2.5) all saw decreases from 2014 emission levels.
Even though the total tons of methane reported increased due mainly to the increase in the number of sources, the average emission per facility has declined.
The average methane reported from each mid-stream compressor station decreased from 106.9 tons in 2012 to 97.5 tons in 2015.
The average emission per well site was 8.3 tons in 2012 and 5.8 tons in 2015. Year to year changes in other emissions are related to a variety of factors, including where wells are drilled and types of equipment being used.
The inventory represents 2015 emissions from unconventional natural gas production and processing operations as well as compressor stations that receive gas from conventional and unconventional well sites and coal gas.
Air emissions from the industry are required to be reported to DEP under Pennsylvania’s Air Pollution Control Act.
“The inventory presents a mixed picture of emissions from the unconventional natural gas industry” said DEP Secretary Patrick McDonnell. “Certain pollutants are decreasing as best practices are implemented more widely through the industry, while others - including methane, a potent greenhouse gas - continue to increase, underscoring the need to do more to detect and fix leaks in order to reduce emissions.”
“While methane emissions increased in 2015, other harmful pollutants like nitrogen oxides (NOx), sulfur dioxide (SOx) and particulate matter (PM2.5) all saw decreases from 2014 emission levels,” said McDonnell.
Click Here for a table showing air emissions in each category from 2011 to 2015.
DEP has proposed changes to the general permits for new well sites and compressor stations that would reduce methane emissions from these sites and facilities. A comment period on the proposed changes closed on June 5, 2017.
More than 10,000 comments have been received on the proposed permits.
The proposed changes include increased leak detection and repair frequency, a specific methane emission threshold for the installation of additional control and added requirements for additional sources.
DEP began collecting emissions data from owners and operators of unconventional natural gas sources in 2011. In 2012, DEP expanded the data reporting requirement to include mid-stream compressor stations that support the conventional natural gas industry.
DEP again expanded the reporting requirements in 2013 to include data from mid-stream compressor stations that support coal-bed methane formations. In 2015, DEP required pigging stations to be reported.
The figures presented are calculated based on the estimated emissions of the equipment on site, per manufacturer specifications.
In addition to compressor stations, other sources and activities of natural gas operations that DEP identified as part of the inventory include dehydration units; drill rigs; fugitive emission sources, such as connectors, flanges, pump lines, pump seals and valves; heaters; pneumatic controllers and pumps; stationary engines; tanks, pressurized vessels and impoundments; venting and blowdown systems; well heads and well completions.
Click Here for a copy of the report.
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