As promised in President Obama’s interagency strategy to cut methane emissions, the EPA has released five technical white papers on “potentially significant” sources of methane and volatile organic compounds (VOCs) in the oil and gas (O&G) sector. The Agency says it will use the papers, along with input from peer reviewers and the public, to determine how best to pursue additional reductions from these sources.
In the strategy, the White House noted that methane accounts for nearly 9 percent of domestic greenhouse gas (GHG) emissions. Although U.S. methane emissions have decreased by 11 percent since 1990, they are projected to increase through 2030 if additional action is not taken. Steps described in the strategy could reduce GHG emissions by 90 million metric tons by 2020, according to the strategy.
Regulations possible by 2016
Regarding the O&G sector, the strategy seeks to build on the success of voluntary programs and targeted regulations to reduce methane emissions. Contemplated steps include an upcoming proposal from the Bureau of Land Management to update standards to reduce venting and flaring from gas production on public lands and Department of Energy (DOE)-convened roundtables to identify downstream methane reduction opportunities.
The EPA says it will use the white papers as a starting point on determine how best to pursue further methane reductions from the five sources. If the Agency decides to develop additional regulations, it will complete those regulations by the end of 2016.
Also, the president directed the EPA to work with the industry through the Natural Gas STAR program to expand voluntary efforts to reduce methane emissions.
Equipment, processes, leaks
The white papers cover the following:
- Compressors. Compressors are mechanical devices that increase the pressure of natural gas to expedite its movement through a pipeline. Vented emissions of methane and VOCs from compressors occur from seal degassing for wet seal centrifugal compressors or packing surrounding the mechanical compression components of reciprocating compressors. These emissions typically increase over time as the compressor components degrade. This paper presents data and mitigation techniques for emissions from compressors, some of which are not covered under EPA’s 2012 New Source Performance Standards (NSPS) for VOCs.
- Completions and ongoing production of hydraulically fractured oil wells. Completion is the process of preparing a well for production. Completions of hydraulically fractured or refractured oil wells can be a source of methane and VOC emissions. Hydraulically fractured oil wells also may produce natural gas along with oil; this gas is often vented during production. This paper presents data and mitigation techniques for emissions from completions and associated gas from ongoing production at hydraulically fractured oil wells, which are not covered under the 2012 NSPS.
- Leaks. As O&G production from unconventional formations such as shale deposits continues to grow, so does the amount of related equipment that has the potential to leak. This paper presents data and mitigation techniques for onshore natural gas leak emissions that occur from natural gas production, processing, transmission, and storage.
- Liquids unloading. Liquids unloading refers to processes used to remove accumulated liquids that can impede the flow of gas from a well to the surface. This paper presents data and mitigation techniques for methane and VOC emissions that can occur during these processes. Liquids unloading is not covered under the 2012 NSPS.
- Pneumatic devices. Controllers and pumps powered by high-pressure natural gas are widespread in the O&G industry. These pneumatic devices may release methane and VOCs with every valve movement or continuously in many cases. This paper presents data and mitigation techniques for emissions from pneumatic controllers and pumps, some of which are not covered under the 2012 NSPS.
The EPA requests that comments on the white papers be submitted by June 16, 2014.
The white papers