In 1997, the plant was converted to operate with either heavy oil or natural gas.
The dry product is mixed with heavy oil recycled from the process.
Any heavy oil used as a road fuel is standard-rated.
The engines mainly ran on heavy oil, using whatever was available.
It contains about 6.3 billion barrels of heavy oil, but is thought to have originally held more.
The same unit of heavy oil, the kind used in competition with gas and coal, is around $2.50.
Specialized techniques are being developed for exploration and production of heavy oil.
The province's first significant production of heavy oil came from the Wainwright field in 1926.
These developments made heavy oil for the first time more than a marginal resource.
Valero will be able to process about 1.8 million barrels a day of heavy oil.