Advocates for protecting the waters of the Straits of Mackinac are raising safety and financial concerns about a Canadian natural gas company’s proposal for an underwater pipeline tunnel.
Enbridge Energy currently operates the Line 5 pipeline, which runs under the Straits of Mackinac, and now they’re proposing to replace it with a tunnel to run the pipeline through.
But experts say the current plan has major safety flaws.
Sean McBrearty, Michigan legislative and policy director for Clean Water Action and campaign coordinator for Oil and Water Don’t Mix, noted Enbridge filed papers with the federal Energy Regulatory Commission claiming they plan to depreciate all of their pipelines within 20 years. But he said the contract with the state to build and operate the pipeline in the tunnel is for 99 years.
“If Enbridge were able to build this tunnel and have it operable by 2028 or ’29, which is about as soon as they’d be able to do something like this, that tunnel would only operate for 11 years before Enbridge would be done using their pipeline system,” McBrearty explained.
Enbridge officials have said the report to the Energy Regulatory Commission is for determining the cost-of-service toll for investors, and does not necessarily reflect the lifespan of the tunnel. Oil and Water Don’t Mix and other groups are calling on Enbridge to suspend activities on the tunnel project until the contract is reviewed.
Brian O’Mara, an environmental engineer with decades of tunneling experience, said the poor quality of the bedrock will make completing the tunnel challenging. He pointed out it is possible an explosion or fire would put workers at risk and many thousands of gallons of natural-gas liquids could be released into the Great Lakes.
O’Mara argued it could be prevented by filling the tunnel with concrete around the pipeline.
“You need air, you need a spark, and you need a fuel to create an explosion or a fire,” O’Mara emphasized. “So if they would have adapted that method — it’s called a sealed annulus — that essentially will eliminate the risks.”
Enbridge has said there is no source of a release that could cause an explosion, but O’Mara contended they have identified dissolved methane in groundwater where the tunnel and pipeline would be constructed. And with flammable and explosive liquids and gas running through the pipeline, there is too much risk with the current design.
