Terminal Operations

Electric current can find damage in underground liners

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A new Council report shows how electricity can be used to “see” damage in the asphalt liners that are intended to contain oil in case of a spill at the Valdez Marine Terminal.

The terminal’s vast crude oil storage tanks are surrounded by a secondary containment system. This system consists of huge containment cells (two tanks per cell) that would act like a bathtub, holding the oil until it can be cleaned up.

To keep oil from leaking into the surrounding environment, these cells are lined with a special type of asphalt. About 5 feet of gravel fill sits on top of this liner.

These asphalt liners can become brittle with age and are susceptible to physical and chemical damage. Over the years, the gravel fill has been removed in a few places to visually inspect the liner. About 20% of the time, holes or cracks were found.

Removing all the fill to visually inspect and repair the liner would be an expensive and time-consuming project, and the excavation equipment could cause further damage to the liner. Alyeska is looking for ways to evaluate the liner without having to excavate.

To help identify the best liner testing methods, the Council has been working with Dr. Craig H. Benson, who has been teaching and practicing environmental and civil engineering for over 40 years, and has extensive experience in containment systems. A new report by Dr. Benson has several recommendations to help the Council provide advice to Alyeska regarding the secondary containment systems at the terminal in Valdez.

This image shows how electric current can flow through holes in a liner, allowing a technician with a sensor to locate damage in the liner.Dr. Benson evaluated several liner inspection techniques and determined that electrical leak location would likely be the best. This type of survey is done by applying electric currents to the ground outside the liner and measuring electric currents on the surface of the fill inside the liner. A solid liner would block the currents. Holes or cracks would allow the current to flow through. Currents that flow through the liner can be detected from the surface, allowing technicians to create a map of damaged areas.

Dr. Benson also analyzed how much of the liner would need to be tested to have confidence that the liner will reliably hold spilled oil. He determined that testing at least 20% of the liner would be enough to estimate how many holes may exist in the liner, with acceptable accuracy. However, 100% of the liner would need to be tested to find all the actual damage.

The importance of an undamaged liner

The Alaska Department of Environmental Conservation, or ADEC, gives Alyeska a 60% “prevention credit” because this secondary containment system is in place. This means that instead of having to provide response equipment to clean up a spill equal to the contents of the largest tank at the terminal (over 23 million gallons), Alyeska only has to provide response equipment and personnel to clean up a little over 8.5 million gallons.*

This is a substantial reduction in the amount of response personnel and equipment.

In May 2022, ADEC notified Alyeska that they needed to identify preliminary methods to evaluate the integrity of the liners by October 2023. Alyeska must identify final methods to evaluate these liners by March 2025.

Dr. Benson’s report is available online: Methodologies for Evaluating Defects in the Catalytically Blown Asphalt Liner in the Secondary Containment System at the Valdez Marine Terminal

*8.5 million gallons, or 204,180 barrels, is the volume of the largest tank, less a 5% prevention credit for drug/alcohol testing, 2% prevention credit for on-line leak detection, and 60% prevention credit for the secondary containment system.

Matt Cullin builds life of growth and success out of expertise in corrosion and failure analysis

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Volunteer Spotlight

Cullin is a member of the Terminal Operations and Environmental Monitoring Committee. Volunteers like Cullin dedicate their time and expertise on committees who advise the Council’s Board of Directors on technical issues related to the safe transportation of oil through Prince William Sound.

At his job as the director of the University of Alaska Anchorage’s BP Asset Integrity and Corrosion Lab, Matt Cullin imagines himself as a detective.

“I do a lot of failure analysis work for the oil and gas industry,” he says. “Basically when stuff breaks, we do the CSI forensics to figure out why things broke and why they failed.”

They get big projects and a lot of smaller failures too. “Every couple of months somebody shows up with an old piece of pipe and asks us to tell them what happened.”

His goal isn’t just to solve the crime, though, he wants to learn how to prevent corrosion. For all of these projects, Cullin says his next question is always “how can you keep it from failing in the first place?”

Volunteering for the Council

Cullin also puts his background in mechanical engineering with a specialty in corrosion, materials, and failure analysis into use for the Council as a member of the Terminal Operations and Environmental Monitoring, or TOEM, Committee. He says working with the committee helps him better understand the pipeline and terminal. The students in his classes at UAA benefit too.

“Students have a lot of questions about the pipeline and the terminal,” Cullin says. “These are engineers who might go to work for the state or Alyeska and for them to have that information before they graduate is pretty neat. It’s not a given, when you get a university degree, that you’ll get to study this applied information that’s relevant to your local installation.”

“It’s a cool symbiotic relationship,” he adds.

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Schantz: Collaboration leads to better solutions for prevention and response

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Photo of Donna Schantz
Donna Schantz

By Donna Schantz
Executive Director

The Oil Pollution Act of 1990 notes congressional findings from the Exxon Valdez oil spill. Included in those findings was the need to foster the long-term partnership of industry, government, and local communities. This is a key piece of the foundation on which the Council was formed.

The Council may not always agree with industry and regulators, but we strive to maintain positive working relationships and build trust. While we do not hesitate to raise concerns when we perceive potential rollbacks in oil spill prevention and response safeguards, it is just as important to recognize when we are in agreement.

I am pleased to report the Council will be supporting Alyeska in a recent appeal they filed with the Environmental Protection Agency (EPA) (page 2). Our independent review verifies that systems Alyeska currently has in place at the Valdez Marine Terminal capture over 99% of the emissions addressed by the rule – a higher reduction goal than is currently being required. The Alaska Department of Environmental Conservation (ADEC) has also voiced support of Alyeska’s appeal to the EPA.

This collaborative approach goes both ways. For example, after months of coordination, Alyeska has also agreed to support a project proposed by the Council to look at the chemical composition and concentration of oxygenated hydrocarbons released from the terminal. Oxygenated hydrocarbons are less studied than other hydrocarbon products and they are potentially toxic in the aquatic environment. Revisions to the scope of work were necessary to satisfy Alyeska’s concerns, mostly related to COVID impacts and their desire to focus resources on their priority operational goals. This is another example of how good communication, strong relationships, and a willingness to work together can lead to solutions that support everyone’s goal of moving oil safely.

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Council supports Alyeska’s appeal to EPA

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In late 2020, Alyeska Pipeline Service Company appealed a July 2020 Environmental Protection Agency air quality rule that would regulate emissions from the crude oil storage tanks at the Valdez Marine Terminal.

Alyeska asserted that the new rule would not result in emissions reductions at the terminal, that local residents would not see air quality benefits, and that Alyeska was already controlling air pollution from the storage tanks using optimal methods.

Alyeska noted that the existing control system at the terminal captures 99.94% of all tank vapors, while the reduction goal for the updated rule is 95%.

The Council hired experts at John Beath Environmental to conduct an independent review of Alyeska’s appeal and their assertions, to determine if the Council should support Alyeska’s appeal or not.

The section of the standards being appealed establishes national emission limitations, operating limits, and work practices for major sources of hazardous air pollutants. Hazardous air pollutants can be harmful to human health and include carcinogenic compounds such as benzene, among nearly 200 other harmful compounds.

In addition to verifying Alyeska’s assertions, the review documented how the implementation of the new rule, as written by the EPA, would impact the amount of hazardous air pollutants coming from the terminal.

The Council’s independent review supports the key arguments in Alyeska’s appeal. The design of the existing vapor recovery system already controls vapors better than the alternatives required by the new rule. Imposing the entirety of the new rule at the terminal would not result in overall, local air quality benefits.

The Council will be supporting Alyeska in their appeal by sending a letter and the final report to the Environmental Protection Agency.

A Review of the Appeal to 2020 Updates to 40 CFR 63, Subpart EEEE by Alyeska Pipeline Service Company

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