Explainer
The WCS differential is the discount at which Western Canadian Select, a benchmark heavy crude blend, trades against WTI, quoted in U.S. dollars per barrel.
WCS is heavier and more sour than WTI, so refiners pay less for it. It is also landlocked, which means barrels must travel by pipeline or rail to reach refineries, and that transport cost comes out of the Canadian price.
Pipeline and export capacity is the biggest driver. When egress is tight, barrels back up in Alberta and the discount widens. When the Trans Mountain expansion opened in May 2024, its added capacity narrowed the discount. Refinery outages, diluent availability and the general price of oil also play a role.
A wider differential hurts heavy oil and oil sands producers, including SAGD operators, because they receive less per barrel. Pipeline and midstream companies that move the barrels are less exposed, and a persistently wide discount can strengthen the case for new egress projects.
We track the differential and the AECO natural gas price when they move enough to change the story for Canadian producers. See the glossary for AECO, Henry Hub, SAGD and boe/d.
Commodity Ape is information and commentary, not investment advice.