The use of so-called “conservative assumptions” in a study done for FERC on LNG tanker safety has resulted in “unrealistic potential consequences that may unduly alarm the public,” the Center for Liquefied Natural Gas (CLNG) said last week.

The purpose of the study was to identify appropriate models and methodologies for estimating the potential consequences of LNG spills from tankers, but according to CLNG, it failed to measure up because it did not include analysis using the latest science and technical advances.

CLNG’s comments were among many others filed in response to the study by ABS Consulting that was commissioned by FERC. The study is titled “Consequence Assessment Methods for Incidents Involving Releases from Liquefied Natural Gas Carriers” (AD04-6) (see NGI May 17).

The comments ranged from those saying the report erred by exaggerating consequences of an LNG spill, to others who suggested the worst case scenarios depicted in the report should be accepted by FERC as “probable,” rather than just “possible.”

CLNG is made up of the major natural gas trade associations, including the American Gas Association, the Interstate Natural Gas Association of America, the Natural Gas Supply Association, and the American Petroleum Institute.

“Our technical concerns focus on shortcomings of the ABS modeling of the rate of release of LNG from a hole in a carrier, the spread of an LNG pool on water, thermal radiation and vapor dispersion calculations…,” CLNG said.

The group pointed to the 40 years of LNG operations, including more than 35,000 cargo deliveries with no LNG cargo tank failure, noting that “the scale of fires or vapor clouds studied in the report have never occurred.”

LNG tankers incorporate multiple layers of protection. For instance, the distance from the outer to the inner hull of the double-hulled vessels is six to 10 feet. Beyond that any foreign object also would have to puncture the cargo tank.

CLNG pointed out that cargo areas and piping are segregated and LNG systems require the use of special materials and advanced control systems, alarms and emergency shutdown devices, as well as vessel fire protection systems. All personnel undergo extensive safety training, and LNG vessel operations are closely monitored by authorities.

Weaver’s Cove Energy, the sponsors of a proposed LNG import terminal in Fall River, MA, said the FERC-sponsored report “has been a lightning rod for public opinion, much of it uninformed. The media, politicians and the public have almost uniformly responded by highlighting (mostly out of context) the more alarming statements set forth in the ABS study. While these statements and concerns are largely qualified by ABS in the ABS study, the qualifications are not reflected in the press reports.”

Weaver’s Cover Energy pointed out there was no peer review of the ABS study, “which would almost certainly have led to the elimination of errors…” Also, the study only skimmed the surface of another important study, using the executive summary but not the follow-up detailed report prepared by Quest in October 2003 modeling the potential for spills in Boston Harbor. “ABS also appeared to ignore the well-publicized reports on the Gas Fountain and Limburg incidents, both of which involved double-hulled tankers.”

Taking the opposite tack and going beyond the ABS study, the Boston Fire Department said FERC should consider the potential for escalating failure and additional damage to a ship and surrounding property that might occur from the release of LNG from a tanker. Failure of one LNG tank that involved a fire could cause damage and fire in additional tanks, the ship itself, surrounding structures and people, according to the filing authored by Joseph M. Fleming, deputy chief of the Boston Fire Department.

Fleming criticized FERC’s existing standards for heat levels resulting from a potential facilities fire, saying they are too high to adequately protect the public. He criticized the National Fire Protection Association code itself, whose code 59A FERC uses, saying the provisions for LNG were written by a committee that included industry and government but did not have representation from the fire service. The use of industry codes “creates a false sense of security,” Fleming said.

The Boston Fire Department official cites the ABS study’s distance limit of 2,800 to 4,600 feet from a fire for serious property damage and loss of life, noting it could reach that limit in three minutes. “How are public safety agencies in Boston supposed to evacuate an area within three minutes, which in Boston, due to the narrow channel could involve hundreds of buildings and thousands of people?” He said there could be as many as 10,000 fatalities if adjacent buildings caught fire.

A Texas research firm said the study evaluates some methodologies with less than credible assumptions and fails to distinguish between probable risk and worst-case risk. The recommendations produced in the study are “weak” in that there is almost no comment or guidance as to the use of the various methods “to determine risk in the real world.” That comment was part of the response filed at FERC by Project Technical Liaison Associates Inc. (PTL), of Spring, TX . The group pointed out that the potential size of a breach in a tanker and consequent release rates of the LNG used for the FERC-sponsored assessment “have near zero probability, especially in areas where a hazard zone would reach any populated area.”

“The release rate from an LNG carrier seems to have been chosen based on assumptions used by LNG project opponents and completely excludes any results of collision or terrorist attack analysis for cargo tank penetrations which might be credible. Also, the assumption that a 5-meter penetration of the outer hull results in a 5-meter penetration of the cargo tank is convenient but not credible…Assumptions are necessary but choosing an assumption which would never occur is an unnecessary distortion of reality and gives misleading results.”

The fact that the report was commissioned and published by FERC — even though it was not done by FERC staff, nor endorsed by the commissioners — gives it a status that “will probably be most useful to opponents of LNG projects as the basis for ‘Even FERC says’ statements,” PTL said.

The PTL response found fault with the initial report’s estimates of the spread on LNG on water, noting the calculation assumed a smooth surface, when even small waves could cause a dramatic difference in the spread. Also, the calculations of the evaporation rate and vapor dispersion rate should use the same wind and water surface conditions.

PTL also found fault with the distance calculated for flammable vapor dispersion following spills on water, saying in part that “the release rate is not credible for any port area; the dispersion over land, i.e., where people are potentially at risk, is not the same as over water.” The PTL comments included point-by-technical-point challenges to the ABS assumptions and conclusions and laid out procedures for establishing actual risk to the public in the real world.

ABS Consulting, meanwhile, said its report should simply be considered as a first step or starting point for the Commission’s efforts to get a handle on the risk associated with imported LNG. FERC should involve a broad cross section of industry stakeholders and the public in coming up with a formula to balance risk with energy requirements, it said.

ABS suggested that risk-based decision-making techniques such as those used by the U.S. Coast Guard could be helpful to the Commission in its own decision-making.

Taking a different tack, a Fall River, MA-based environmental organization, Green Futures Inc., said FERC should accept the worst-case scenarios labeled as “possible” in the ABS study as “probable.” The group, which has been opposing the location of the Weaver’s Cove LNG terminal near Fall River, cited the attack on the double-hulled French oil tanker Limburg in 2002 and the terrorist attack on the USS Cole to bolster its case.

Green Futures cites calculations by Professor James Fay of MIT, which show a greater potential spread of LNG and greater fire risk. The group used the example of the Limburg, which was attacked by a small boat with explosives that tore a gaping hole in the double-hulled oil tanker, resulting in a 90,000-gallon spill and a massive fire. The tanker rupture was at least 16 feet in diameter. The models should assume that more than one compartment in a tanker would be ruptured, the group said, since surrounding compartments may be affected if one compartment is ruptured.

Further, Green Futures claims that it would be almost impossible to defend against a terrorist attack in a narrow ship channel, such as Fall River, where the channel is about 600 feet from shore for most of the five miles in the city’s harbor.

The environmental group said any discussion of LNG hazards should include a investigation of the Skikda, Algeria fire at a liquefaction facility, although that was not on water, since it provides evidence regarding vapor clouds.

Weighing in on the LNG side, the International LNG Alliance (ILNGA) and the 75-year old International Gas Union (IGU) said the ABS report reviews “a limited number of theoretical models and is similarly limited in its depth of analysis.” The two groups advised there is an extensive body of work on the subject that should be considered.

The two gas organizations noted that evidence does not support that the inside hull of a tanker would be punctured to the same extent as the outside hull, nor the outflow rate or dispersion data of LNG used by the study. The group challenges several other procedures used in the FERC report, pointing to the need to encompass other available research.

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