Enbridge Inc on Friday endorsed either an underwater tunnel or trench to replace a section of its 65-year-old energy pipeline that travels under a stretch of the U.S. Great Lakes in Michigan. Some local officials want the line removed to prevent the potential for a spill into lake waters. The state of Michigan proposed moving the line into a tunnel under the lake bed and asked the company to evaluate it and other alternatives. The Canadian pipeline operator said a tunnel would cost between $350 million and $500 million and take five to six years to assemble. A concrete-lined tunnel built as much as 100 feet below the lake bed and 350 feet below the surface of the lake would prevent an oil spill from reaching the water, the company said. The alternative, an open-cut trench, would cost between $250 million and $300 million and take four […]