The Keystone oil pipeline could return to full capacity next week if the necessary repairs to an electric substation are completed without major supply chain disruptions for replacement parts, S&P Global Platts reported Wednesday, citing an unnamed company source.

Operator TC Energy (TRP) said there was no timeline yet for completion of repairs and restoration of power, after the 590K bbl/day pipeline was running at a reduced but unspecified rate for a third day on Wednesday.

The outage was caused by vandalism of a power substation transformer in South Dakota, and a criminal investigation is underway.

Depending on the length of the outage, the incident could push differentials for Western Canada crude lower and lead to significant storage builds, according to S&P Global, as the market depends heavily on Keystone to move crude out of the region.

TC Energy (TRP) declared a force majeure for its Keystone system earlier this week.

TC Energy (TRP) “enjoys remarkably stable cash flows regardless of macroeconomic conditions, which gives it a utility-like quality,” Power Hedge writes in an analysis published recently on Seeking Alpha.