An effort by Energy Transfer Partners LP to expand its Mariner East 2 pipeline ran into local resistance, and Pennsylvania authorities halted construction earlier this month. Some of North America’s biggest new pipeline projects are already in the ground. As environmentalists and local activists make it extraordinarily difficult to build new oil and gas lines, energy companies are working around the opposition by supersizing old pipes that already crisscross parts of the continent. Executives at some of the biggest pipeline operators in the U.S. and Canada, including Enbridge Inc. ENB 0.08% and Kinder Morgan Inc., KMI 0.93% say they pivoted to the strategy as plans for new pipelines came under attack. For decades, new pipeline projects rarely drew attention, much less ire. “We used to just show up with a map,” said Al Monaco, president and chief executive of Enbridge. “Now we engage with the local communities and indigenous […]