The Alaska Highway route is a bargain and safe, compared to the rival proposal for an offshore international Arctic natural gas pipeline known as the over-the-top route, according to an engineering study commissioned by the Yukon government. Laying pipe along the floor of the Beaufort Sea between Prudhoe Bay and the Mackenzie Delta confronts the North American industry with risks it has never faced and probably would cost almost $2 billion more to overcome, according to the report.

Risks identified by the engineers for offshore Arctic pipelines range from short and unpredictable open-water construction seasons to novel hazards such as “strudel scour,” or powerful flows of half-frozen fresh water streams into the Beaufort from its coastline.

In breaking down the two proposed routes, the Canadian study estimates that the Alaska Highway version of the northern gas megaproject would cost $8.97 billion: $4.22 billion for 1,256 miles of pipe in Alaska and the Yukon; $1.12 billion for 447 miles in the Northwest Territories and British Columbia; $1.7 billion for 1,012 miles in Alberta and Saskatchewan; and $1.93 billion for 890 miles across the U.S. Midwest to Chicago. The engineers estimate an over-the-top project, long considered to be less expensive, would actually cost $10.87 billion: $4.41 billion for 368 miles of offshore pipe along the Beaufort coastline of Alaska and the Northwest Territories; $2.89 billion for 1,149 miles on land in the NWT and BC;, $1.63 billion for 972 miles in Alberta and Saskatchewan; and $1.93 billion in the United States.

The figures are an attempt to take into account the risks of innovation in the Arctic. The Canadian engineers noted, “there are many unresolved and complex technical issues when considering the design, construction and operation of a northern offshore pipeline. These issues will translate into long construction delays, substantial cost overruns and significant reliability and environmental risks.” Yukon Economic Development Minister Scott Kent released the document last week before attending the Arctic Gas Symposium in Houston. However, with the report’s release, proponents of an over-the-top route were not discouraged.

In Calgary, the study did not worry Harvie Andre, the engineer and former Conservative member of Parliament who represents over-the-top’s sponsors, the Arctigas consortium, in Canada. Andre urged the critics to fold up their Mercator-projection maps and look at globes. Those show it is nearly a straight line south from Prudhoe Bay along the Alaskan and territorial coast then through the Mackenzie Valley to Alberta, and Andre maintained that every independent analysis of cost shows that direct line to be the lowest-cost route.

Andre also dismissed criticism of the proposal from the Yukon as politically inspired, from a government hungry for economic activity in its jurisdiction. In Houston, meanwhile, Kent’s message was that the need for northern gas development is too urgent to await solutions to the issues raised by the over-the-top proposal (see Daily GPI, Nov. 30). Kent’s department commissioned the technical report from two engineering consulting houses: PFL Inc. Consultants in Calgary and Wolf Island Engineering in Whitehorse, and the report boasts blue-chip authors: Don Dempster at Wolf Island, former director-general of engineering with the Canada Oil and Gas Lands Administration; and Mario Fernandez at PFL, a 32-year engineering veteran with international as well as northern experience.

The engineers observed that the Beaufort is solidly covered in ice for eight-to-10 months of any given year, and that there is in any year a 30% chance that the open-water season will last only 30 days. Drifting floes remain a hazard at all times. If contractors succeeded in laying a pipeline with strengthened equipment that would all have to be shipped long distances north, the ice would pose constant hazards to operations. The risks are highest in an area known as the transition zone. Along Arctic shorelines, the term refers to a shifting place where land-fast ice shelving outwards from the coast meets floating sea ice.

The engineers calculate that to escape the danger of being ruptured by keels of ice formations scouring the seabed, a Beaufort-floor pipeline would have to be protected in a four-metre trench twice as deep as the current standard in offshore pipeline construction. The challenge is heightened by the Beaufort Sea floor. The bottom is sandy and caves in easily requiring any trenches to be extra wide in order to achieve the required depth. In the Beaufort transition zone, the engineers say “the ice is constantly moving and shifting due to wind and current action.

An offshore pipeline will have to be installed, in part, under this transition zone and, as a result, will be inaccessible by sea- and ice-going vessels for many months each year. This means that any incident, pipeline repair or, especially, a leak or rupture, cannot be attended to until the next open-water season.”

The Yukon report also warned that “for some of the technical issues, there are no known solutions yet…for other technical issues, the solutions will be prohibitively expensive.” The prediction is based on results of work done by the Geological Survey of Canada and incorporated, at the request of the U.S. Fish and Wildlife Service, into a review of a BP Exploration Alaska proposal titled the Liberty Pipeline for a six-mile stretch of offshore pipe near Prudhoe Bay. The Canadian engineers say that “to solve the ice scour problem, a pipeline company may have to resort to innovative solutions such as pipe-in-pipe or twin pipelines. While this is realistic for smaller, near-shore projects, it will prove to be economically unacceptable for a large-diameter, long-distance pipeline.”

©Copyright 2001 Intelligence Press Inc. All rights reserved. The preceding news report may not be republished or redistributed, in whole or in part, in any form, without prior written consent of Intelligence Press, Inc.