Perspective on the Cook Inlet Natural Gas Leak

March 15, 2017 in Blog

The last two weeks has generated no small out of amount of speculation and fear mongering from some parties looking to capitalize on a minor natural gas leak in Alaska’s Cook Inlet.  During events like this, an accurate assessment of the situation is absolutely critical to initiate a proper response – for the operator, for regulators, and for the public.  Speculation, misinformation, or just making things up has absolutely no place.   Top priorities should always be safety, transparency and an accurate accounting of the facts.

While no leak is acceptable, the response from the operator in this event has demonstrated all of these traits.  That isn’t just the opinion of Arctic Energy Center, it also happens to reflect the evaluation of the response by regulators which have made it crystal clear that the natural gas leak is being handled in the most expedient and safest manner possible.

Sadly, some are resorting to the unproductive tactic of conjuring unfounded implications to an event that has no discernable impact to the environment nor the public.  In an attempt to shed light, rather than conjecture, AEC offers the following question and answer list to help address some of the most common questions being asked.

Is the leak dangerous to the public or the environment?

No, that is the assessment according to the experts in the field and observations from both the company and the regulators.  To date there have been no indications of harm to aquatic species or any discernable negative impacts to the air or water.  The publically available video of the release creating bubbles at the water’s surface was filmed by the operator.  According to reports to date, the impacted area of water surface is approximately 10-15 feet.

How is the leak being monitored?

In coordination with regulators, the operator began onsite assessment of the release and worked to approve a more comprehensive analysis of the incident.  On March 14th, Alaska’s Department of Environmental Conservation (ADEC) approved the operator’s submitted monitoring plan.  While ongoing monitoring from existing infrastructures and vessels continues, ADEC’s approval allows for much greater analysis and oversight.

How big is the leak?

The leak is classified as minor by experts and scientists.  A 2016 analysis of methane emissions from the Canadian Journal of Engineering offered a published study which included classifications on the size of methane releases.  No matter if it was natural or industrial in cause, a “minor” leak classification was given when the release rate is less than 0.1–1 kilograms per second.  This amount is well below the discharge associated with the Cook Inlet release.  The Journal’s classification states:

“A leak is a release from faulty equipment and infrastructure. These can be categorized into three groups according to leakage rate: major (greater than 10 kg/s), medium (1–10 kg/s), and minor leaks (0.1–1 kg/s). Smaller leaks are often not detected, and can thus occur over longer times.  “Current Understanding of Subsea Gas Release: A Review” by Jan Erik Olsen and Paal Skjetne (2016-The Canadian Journal of Chemical Engineering)

Are there other sources of methane emissions besides those from fossil fuel development?

Methane is a naturally occurring gas and can be emitted by both natural sources and through industrial activities. Methane exists naturally in places like wetlands and subsurface hydrocarbon reservoirs (regardless of whether or not they are developed).

The Arctic region and its oceans have long been associated with methane seepage, but recently, other areas, such as the Atlantic Ocean, have been identified as regions where widespread methane seepage occurs or could occur as well.

For greater context on naturally occurring methane leaks, one can compare the Cook Inlet release to naturally occurring methane leaks across the state of Alaska.   A 2012 study in Nature Geoscience found that 80,000,000 kilograms of methane, or 0.08 Tera grams, naturally leaks from Alaska’s permafrost annually, far outpacing methane leaks from anthropogenic sources like pipelines.  The study found that there are over 150,000 “highly ebullient macroseep vents” in Alaska.

Why wasn’t the leak detected sooner?

The natural gas leak was self-reported by the operator on February 7th following company monitoring of the Cook Inlet infrastructure.  While the leak may have begun emitting natural gas weeks before the siting by the operator flyover, federally approved and regulated monitoring systems may not immediately identify such minor leaks in the system.  As the Canadian Journal of Chemical Engineering study states, “Smaller leaks are often not detected, and can thus occur over longer times.”  In this case, the leak was reported and addressed by the operator immediately following its identification, allowing corrective actions to diminish the flow rate and a take corrective action.

Why not shut in the gas pipeline entirely?

The natural gas pipeline feeds four existing platforms in the Cook Inlet.  Cutting off supplies of natural gas would necessitate shipments of diesel fuel to keep existing facilities functional for existing personnel needs and obvious safety implications.  Lightering fuel in icy water to keep minimum energy needs available at each platform poses an elevated and unnecessary risk for operations.  Secondly, the pipeline contains residual amounts of oil from use by the previous owner of the pipeline system.  As such, the gas serves to keep positive pressure in the line and negate any water incursion in the system, and causing a potential oil release to the Inlet.  The decision to keep the line functional until a fix is attained was assessed as the best option by both the operator and state and federal regulators.