Market Snapshot: Trans Mountain Expansion eases pipeline constraints and increases exports to overseas markets

Release date: 2025-09-03

The Trans Mountain Expansion Project (TMEP) came online in May 2024, nearly tripling the capacity of the Trans Mountain System to a total of 890 thousand barrels per day (Mb/d). This increased total western Canadian crude oil export pipeline capacity by 13% and export capacity to tidewater in western Canada by about 700%.^Footnote 1 Since TMEP’s first month of ramping up, the expanded Trans Mountain System has averaged 82% utilization. More broadly, constraints have eased on all of Canada’s largest export pipelines over this period and Canadian crude oil prices have improved relative to international benchmarks.

Figure 1: Monthly throughput and available capacity on the Trans Mountain System

Utilization of the Trans Mountain System since the TMEP Began Service

The Trans Mountain System has been more than 75% full every month since TMEP came online, except for the ramp up period in May 2024.^Footnote 2 From June 2024 to June 2025^Footnote 3, the Trans Mountain System averaged 82% utilization, ranging from a low of 76% in December 2024 to a high of 89% in March 2025.

Since TMEP entered service, approximately 80% of the Trans Mountain System’s capacity (707.5 Mb/d) is now reserved for committed shippers with long term take-or-pay contracts and the remainder (approximately 182.5 Mb/d) is made available on a monthly basis for uncommitted (also known as spot) shippers. From June 2024 to June 2025, committed capacity was effectively fully utilized each month, averaging 99% utilization.

Compared to pre-TMEP levels, the Westridge delivery point^Footnote 4—at Trans Mountain’s marine terminal located in the Port of Vancouver—has seen the largest increase in throughputs, which is driven primarily by heavy oil exports (and some light oil exports) (Figure 1). These volumes are being exported by marine vessel to the U.S. West Coast and Asia. An average of 23 vessels per month departed from Westridge marine terminal between June 2024 and July 2025.^Footnote 5 Since the startup of TMEP, Canadian crude oil exports to countries other than the U.S. have more than tripled.^Footnote 6

Light crude oil and refined petroleum products also continue to be delivered to the Burnaby delivery point to serve Parkland’s Burnaby Refinery,^Footnote 7 Suncor’s Burrard Products Terminal, and surrounding areas. Additionally, the Sumas delivery point, which connects with the downstream Puget Sound Pipeline for deliveries of crude oil to Washington State refineries, has continued to be at capacity.

The Trans Mountain pipeline historically transported mostly light oil, but heavy oil has increased to approximately match light oil volumes since the TMEP came online.

Easing capacity constraints on export pipelines

In the months leading up to the completion of the TMEP, all major oil pipelines out of western Canada were running at or near capacity, as Canadian oil production increased to record levels. Shipper requests (or nominations) to use export pipelines significantly exceeded capacity, resulting in a large rise in apportionment on the largest western Canadian oil pipelines (Trans Mountain, Enbridge Mainline and Keystone) in late 2023 and early 2024.^Footnote 8

Since the startup of the TMEP, with Canadian oil production at new highs, there has been no apportionment on the Trans Mountain System. On the Enbridge Mainline and Keystone, apportionment has fallen significantly while their total utilization remained at or near capacity. Overall, oil export pipeline capacity from western Canada continues to be highly utilized (Figure 2). Additionally, since TMEP entered service, Canada’s crude-by-rail exports^Footnote 9 have fallen to annual-average levels not seen in over a decade.^Footnote 10

Figure 2: Crude oil volumes transported from western Canada relative to available pipeline capacity

WCS price differential narrowed after the TMEP entered service

In the months leading up to the startup of the TMEP, the price differential between Western Canadian Select (WCS) and West Texas Intermediate (WTI) had widened to an average of about US$18.70 per barrel in the period of September 2023 to April 2024.^Footnote 11 After the startup of TMEP, with total pipeline capacity no longer being constrained out of western Canada, the differential narrowed to an average of US$12.00 per barrel over the period of June 2024 to July 2025.

This means western Canadian oil has been worth more than if the differential had remained wider, like it was in the period leading up to the expansion. A US$12.00 per barrel differential is more in-line with historical levels seen in periods when markets did not face constrained pipeline capacity.

Figure 3: WTI-WCS monthly average price differential

Date modified:

2025-09-03