Energy Issues
Methane emissions from fossil fuel development around the world are up to 60% greater than estimated by previous studies, according to new research led by scientists from the U.S.’s National Oceanic and Atmospheric Administration and the Cooperative Institute for Research in Environmental Sciences at the University of Colorado in Boulder.
The study found that fossil fuels contribute between 132 million and 165 million tons of the 623 million tons of methane emitted by all sources, every year. That’s 20% to 25% of total global methane emissions, and 20% to 60% more than previous studies estimated. The majority of oil and gas methane leakage comes from a handful of countries: the top seven emitted over half of the global total in 2012; the top 30, including the EU, accounted for three-quarters.
A number of initiatives are underway globally to mitigate methane release and its effects. In the U.S., these have focused on methane capture, and on creation of a set of rules by governmental regulatory bodies, to limit methane emissions.
Capture. Although research on methane capture for reuse is ongoing in a number of areas by various organizations, significant strides have been made in some programs. For instance, a research team, made up of Amitesh Maiti, Roger Aines and Josh Stolaroff of Lawrence Livermore National Laboratory; and Professor Berend Smit, researchers Jihan Kim and Li-Chiang Lin at UC-Berkeley and Lawrence Berkeley National Lab, performed systematic computer simulation studies on the effectiveness of methane capture using two different materials. Those materials are liquid solvents and nanoporous zeolites (porous materials commonly used as commercial adsorbents—https://www.llnl.gov/news/lawrence-livermore-scientists-discover-new-materials-capture-methane).
Unlike carbon dioxide, the largest emitted greenhouse gas, which can be captured both physically and chemically in a variety of solvents and porous solids, methane is completely non-polar and interacts very weakly with most materials. “Methane capture poses a challenge that can only be addressed through extensive material screening and ingenious molecular-level designs,” said Maiti.
Through an extensive study, the team found that none of the common solvents (including ionic liquids) appears to possess enough affinity toward methane to be of practical use. However, a systematic screening of around 100,000 zeolite structures uncovered a few nanoporous candidates that appear technologically promising.
Zeolites are unique structures that can be used for many different types of gas separation and storage applications, because of their diverse topology from various networks of the framework atoms. In the team's simulations, one specific zeolite, dubbed SBN, captured enough medium-source methane to turn it to high-purity methane which, in turn, could be used to generate efficient electricity.
Preventive legislation. While the drive to develop and improve methane emission capture technologies continues, the U.S. Bureau of Land Management (BLM) has introduced rules intended to reduce the release of stray methane into the atmosphere, as detailed by Van Ness Feldman LLP (BLM's Final Methane and Waste Prevention Rule Creates Compliance Uncertainty, Nov. 21, 2016, http://www.vnf.com/blms-final-methane-and-waste-prevention-rule-creates).
As stated by Van Ness Feldman, “On Nov. 18, 2016, the [BLM] announced that it has finalized a rule intended to reduce the waste of natural gas that results from onshore flaring, venting, and leaks by oil and gas production on federal and tribal lands. BLM has said that the Final Rule—which is entitled “Waste Prevention, Production Subject to Royalties, and Resource Conservation”—will modernize existing regulations to reflect advancements in oil and gas production, in an attempt to reduce natural gas waste, curtail air pollution, and provide a beneficial return on public resources for states, tribes, and federal taxpayers.” The paragraphs below provide a brief summary of the key regulatory and policy changes reflected in the Final Rule. Note the uncertainty remaining with respect to its enforcement and validity under the Trump administration.
Specifically, the rule includes several provisions for operators to follow. They should evaluate opportunities for gas capture and prepare a waste minimization plan prior to drilling a development well.
Operators are also told to refrain from venting gas, except in limited circumstances. It further requires that operators replace “high-bleed,” continuous pneumatic controllers with low/zero bleed controllers; replace pneumatic diaphragm pumps with solar pumps or route the pumps to a flare; and capture or flare gas from storage tanks that vent more than six tons of volatile organic compounds annually.
Companies are told to use “best management practices when unloading liquids from wells. Likewise, operators must capture, flare, use or re-inject gas released during well completions. An operator may request exemption from these requirements, but only where it can be demonstrated that compliance would cause the firm to cease output or abandon reserves.
Operators must also capture most of their gas after accounting for specified volumes of allowed flaring. Finally, they are instructed to conduct leak detection and repair (LDAR), “using instrument-based systems for identifying and repairing leaks. The U.S. has done a fairly good job of reducing methane emissions, lowering output by more than 15 million metric tons per year since 2011, as have some other countries. But, the global economy, for the most part, has not. It is time for the entire world to commit to significantly lowering methane emissions. 
