Cogeneration power plants in the fire-ravaged Canadian oil town of Fort McMurray were operating at about 18 percent of capacity early Sunday, down from around 30 percent Friday afternoon, as oil sands producers in the area continue to shut their operations.

Cogeneration plants produce electricity and steam. The electricity powers oil sand operations with any surplus energy sold to the local grid, while the steam is used to cook the oil sands to produce crude.

There are about 3,200 MW of power cogeneration capacity serving the oil sands industry in the province of Alberta, about two-thirds of which is located in the Fort McMurray area.

Of the roughly 2,200 MW of cogeneration capacity in the fire-ravaged area, about 650 MW was operating on Friday afternoon while less than 400 MW was operating Sunday morning, according to data from the Alberta Electric System Operator, the operator of the province's power grid.

Before the fire reached Fort McMurray, the cogeneration units in the area were producing about 1,300 MW of power, according to local media reports.