Whitehorse’s new liquefied natural gas facility is very unlikely to explode and take out part of the city with it.
That was one of the take-home messages from Thursday’s tour of the LNG plant, which focused heavily on the safety features at the new facility.
“We have flame and gas detection, we have wind monitoring, we have cameras, we have a guy that’s in the control centre 24 hours a day, seven days a week looking for the alarms and responding,” said Guy Morgan, director of operations with Yukon Energy. “To the greatest extent possible, we’ve looked at the safety on this.”
The plant, located near Yukon Energy’s hydro facility on Miles Canyon Road, is fenced in and partly enclosed by a vapour barrier designed to prevent clouds of methane gas from drifting along the ground in case of a natural gas leak.
Inside the compound, three large, cylindrical white tanks contain the city’s liquefied natural gas supply. Two of them are currently full, and the third will likely be filled in the near future.
If one of those tanks starts to leak, the plant is designed to funnel the liquid gas into a concrete containment pit, where it will be left to vaporize and disperse into the atmosphere. The containment pit can hold 110 per cent of the volume of one of the three tanks.
In the tanks, the liquefied gas is kept at -162 degrees Celsius. But during a spill, it will begin to vaporize as soon as it warms up. Shannon Mallory, an environmental coordinator at Yukon Energy, said it would take about 20 hours for the full volume of one tank to convert to gas.
Even if the gas were to catch fire in that containment pit, Mallory said, it would create a “lazy flame” rather than an explosion. She estimated it would take four hours for an entire tank’s worth of gas to burn off.
Though natural gas in its liquid form is not flammable, natural gas vapours can ignite. In 2014, an explosion at an LNG facility in Washington State punctured one of the LNG tanks on the site, raising fears that leaking vapours could produce another explosion. The incident prompted an evacuation in a three-kilometre radius around the plant, though no secondary explosion occurred.
At the Whitehorse facility, the natural gas will be used primarily during peak hours in the winter, during droughts, and through long-term outages. When the system is turned on, liquid gas from the tanks is heated and vaporized, then delivered by pipeline to the two generators. That process can take 20 or 30 minutes if the system hasn’t been running recently and the tank pressure is low.
Morgan said the LNG generators can run for 80,000 hours before needing a major overhaul.
“Gas engines are less maintenance-intensive, which means we don’t need to change the oil as often because we are not burning diesel fuel in them, so it’s a nice clean burn,” he said.
Except when the tanks are being filled, the plant will be largely unmanned. Gas and flame detectors should trigger an automatic shutdown of the facility in case of an accident, though the site can also be shut down manually.
The LNG plant was built to replace two diesel generators that had reached end of life.
Brad Cathers, the minister responsible for Yukon Energy, said the LNG generators are predicted to save $700,000 in 2016 and $2.1 million in 2018 compared to new diesel generators.
Last week, the News reported that the LNG plant will not be used to restore electricity during short-term outages. At the tour on Thursday, Yukon Energy president Andrew Hall said the natural gas generators will typically be used for outages that last longer than four hours. For outages that are predicted to last that long, the diesel generators would be used to restore power, and then the LNG generators would take over.
“With diesel, engines pick up load quicker, so we can get the lights on faster with diesel than with LNG,” he said.
Hall said it’s too soon to say what will happen when the rest of Whitehorse’s diesel generators reach end of life.
Sally Wright, a renewable energy advocate and an outspoken opponent of the LNG plant, was among those who attended the public tour of the facility. She said the tour helped alleviate her safety concerns.
“It’s a safe place,” she said. “It allayed my fears, but it didn’t really answer my questions about what a stupid project it is.”
Wright said she still believes the government should have chosen to replace the aging equipment with new diesel generators, which she believes would have cost less. She said the difference should have been invested in renewable energy.
Wright is also calling for another public meeting that will be more accessible to people who can’t take time off work.
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