Great Lakes Tunnel Approves Design, Build Companies
Earlier this month, Canadian multinational energy transportation company Enbridge Inc. (Calgary, Alberta) announced that it has hired two companies for the design and build contracts for the construction of an oil pipeline tunnel.
The tunnel is expected to run beneath the Great Lakes channel linking Lakes Huron and Michigan.
About the Project
In July 2017, Michigan Pipeline Safety Advisory Board released an assessment of Enbridge Energy’s Line 5 liquid pipeline that looked at the risks related to keeping the current pipeline—which was built in the 1950s and crosses under the Straits of Mackinac—as well as alternatives, including new lines in or around the straits, a new pipeline elsewhere or a complete abandonment of the line.
The assessment was prepared by Dynamic Risk Assessments Inc.
Enbridge pushes ahead with planning for Great Lakes pipeline tunnel despite pending court challenge pic.twitter.com/yMRBBCHibE— mycanadiantimes (@mycanadiantimes) March 8, 2020
According to Dynamic Risk, the biggest threats to the existing pipeline are anchor hooking, incorrect operations, vortex-induced vibration and spanning stress. A spill in the straits, the firm contends, would likely incur $100-200 million in costs, about 60% of that covering environmental cleanup. Those figures account for what Dynamic Risk calls “objective assessments of credible risks,” and not a worst-case scenario.
By June 2018, Enbridge Energy released its report to the state of Michigan on possible replacement of its Line 5 pipeline, concluding that a tunnel or an open cut with secondary containment would be feasible methods for replacing the 65-year-old liquids pipeline.
In the report, Enbridge says its study, performed by independent consultants, showed a tunnel created by a tunnel-boring machine could be a feasible method of installing a new pipeline to replace Line 5. Such a tunnel would have a 10-foot inside diameter and would stretch four miles long, 100 feet below the deepest part of the Straits.
A tunnel would cost $350-500 million, Enbridge says, and if this alternative were chosen, the dual 20-inch pipelines comprising the current Line 5 would be replaced with one 30-inch line. The concrete tunnel would be lined with precast concrete tunnel lining; the annulus outside the tunnel lining would be filled with cement grout.
The other alternative the company says could work would be an open cut with a secondary-containment pipeline around a new 30-inch Line 5. This approach would cost $250-300 million and would involve trenching the pipeline for the first half-mile or so from the shoreline, then laying the majority of the line on the lake bed with an engineered protective cover.
The pipe-in-pipe system would involve a 30-inch steel pipeline surrounded by a 36-inch secondary-containment line with low-friction spacer rings in the space between. The outer pipeline would be engineered to withstand pressures greater than the line’s operating maximum.
Although, a worst-case spill on Line 5, according to a risk analysis by Michigan Technological University, could affect more than 400 miles of shoreline on Lake Michigan and Lake Huron and come with a price tag of more than $1.8 billion.
A lawsuit filed at the end of August 2018 by the Environmental Law and Policy Center and the National Wildlife Fund alleged that a top Coast Guard official testified under oath in front of Congress the year before that the service was not adequately prepared for a worst-case spill on the line, though the Coast Guard does have a contingency plan in place to do just that.
In December, Michigan Senate voted to create the three-member Mackinac Straights Corridor Authority, an entity that would oversee the construction of the replacement pipeline and a new utility tunnel.
According to Crain’s Detroit Business, creating the panel is an essential step toward replacing the underwater pipeline. The project is slated to take seven to 10 years to complete, and the cost of replacing the pipeline could range from $350-500 million, all paid for by Enbridge, but owned by the Mackinac Bridge Authority.
However, in May 2019, the law to create the three-member Mackinac Straights Corridor Authority was ruled unconstitutional by the state attorney general. Gretchen Whitmer, Michigan’s current governor, asked for Attorney General Dana Nessel's legal opinion. In Whitmer’s view, the law is invalid. Earlier last year, Whitmer halted state agencies’ attempts to facilitate construction on the tunnel.
State legislature Republicans have dismissed Whitmer’s opinion, citing that a judge has already allowed the law to be as is.
The state attorney general’s communications director, Kelly Rossman-McKinney, noted that the attorney general thinks the opinion will be upheld. If that happens, though, consumer groups are likely to sue, according to the Engineering News-Record, given that Upper Peninsula residents oppose measures that would take Line 5 out of service without replacement.
What’s Happening Now
Despite years of dispute over the pipeline project, Enbridge has announced that Great Lakes Tunnel Constructors—a partnership between Jay Dee Contractors Inc. (Livonia, Michigan) and Obayashi Corp. (Tokyo)—will build the tunnel and Arup (London) will design it.
The project is expected to break ground on the tunnel sometime next year, should the project not be postponed or canceled in a response to opposition.
Already, State Attorney General Dana Nessel has been reported to have filed a separate lawsuit seeking the shutdown Enbridge’s existing Line 5 pipes. Previously, Nessel appealed the Michigan Court of Claims ruling last October.
Other environmental advocacy groups have also voiced their concern about the pipeline and wishes to have the line decommissioned. Advocacy group, For Love of Water, has gone as far to accuse Enbridge of failing to seek authorization for the project through the Great Lakes Submerged Lands Act.
Regardless of the legal challenges and opposition, Enbridge spokesperson Ryan Duffy says that the success in court so far has created a path where the company can safely move forward. “We feel like it’s time now for Enbridge and the state to work together and keep the project moving,” he added.
Enbridge is continuing to seek construction permits from the Michigan Department of Environment, Great Lakes and Energy and the U.S. Army Corps of Engineers.
Currenty, Line 5 carries 23 million gallons of crude oil and natural gas between Superior, Wisconsin, Sarnia and Ontario each day. A roughly 4-mile-long segment divides the two pipes that run beneath the Straits of the Mackinac.