Enbridge’s 2.8-MMb/d Mainline system from Alberta to the U.S. Midwest has been running close to full, as have the other crude oil pipelines out of Western Canada. The Mainline is a unicorn among these pipes, however, in that none of its capacity — zilch — is under long-term contract. Instead, under Enbridge’s almost nine-year-old Competitive Tolling Settlement (CTS), shippers each month submit nominations stating the volumes of crude they would like to transport the following month on various elements of the Mainline system, then hope they get what they need when the available capacity is divvied up. In an effort to give producers and refiners the pipeline-capacity certainty they say they want — and to optimize the efficiency of the Mainline’s operation — Enbridge has been working with shippers on a CTS-replacement plan that would commit as much as 90% of the capacity on the pipeline system to shippers who enter into long-term contracts. Today, we continue this blog series with a look at how the prospective “priority access” capacity-allocation system is shaping up, how it might affect planned pipeline projects, and how it may facilitate the transport of a lot more crude from Alberta to the U.S. Gulf Coast.