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Regulators Order Shell's Prelude LNG to Shut Down for Safety Review

Prelude flng
File image courtesy Shell

Published Dec 24, 2021 12:15 PM by The Maritime Executive

After a Australia's National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA) has ordered Shell to keep its massive Prelude LNG offshore gas facility shut down until it can prove that it has made safety improvements. 

Earlier this month, a small fire in an electrical compartment knocked Prelude's power supply offline, forcing a shutdown and a rush to get generators back up and running. According to NOPSEMA, that restart effort failed repeatedly, and Prelude's power kept shutting down for three days. With HVAC offline, heat exhaustion from rising temperatures inside the vessel put two workers in Prelude's hospital bay. 

According to WA Today, Prelude's automatic safety systems shut down all production systems and began flaring gas when the fire was detected. This took out the gas supply for the facility's steam-fed turbine generators. An emergency diesel generator failed to start, and two backup diesel generators kept tripping and failing as well. 

The power failure briefly took down all comms on the platform, and the crew reportedly had resort to calling a nearby support vessel over VHF to get messages out. The support vessel served as a relay station, using a satellite phone to send text messages back to management on shore.

“What happened on the Prelude under Shell’s watch earlier this month is unforgivable,” said Brad Gandy, spokesman for the labor group Offshore Alliance and local secretary for the Australian Workers Union. "This is not the first time similar failures have occurred on the Prelude and clearly Shell has not learned from its past mistakes.”

NOPSEMA's inspectors boarded Prelude on December 9-10, and their report was not favorable. "The Inspectors concluded that the operator did not have a sufficient understanding of the risks of the power system on the facility, including failure mechanisms, interdependencies and recovery," NOPSEMA said.

The inspectors found that the loss of power knocked out comms, access to the ship's safety documentation, evacuation systems for helicopter or boat transfer, lighting, potable water, safety systems, HVAC, sewage treatment and some of its core process equipment. 

Crewmembers told WA Today that they were managing human waste manually because the sewage system was shut down, and without power for transfer pumps, they had to shuttle cans of diesel around by hand to keep a backup generator running. 

The problems aboard Prelude could not have affected a more sophisticated ship. Along with the $13 billion aircraft carrier USS Gerald R. Ford, Prelude is a top condender for the title of the most complex and expensive vessel ever built: though its final cost has not been disclosed, it is estimated at between $12-17 billion. After the heavy-lift ship Pioneering Spirit, Prelude is the world's second-largest vessel by displacement. 

Concluding that Shell has not shown an ability to manage such a complex asset, NOPSEMA ordered that Prelude must be shut down until the operator can convince regulators "that the facility can safely recover essential power and associated essential services following a loss of power, and that the safety systems and essential support systems operate to maintain safety of personnel."