This Calgary Petro-Canada station has already run out of regular and higher grade fuel. (Karen Wade/CBC)

A Petro-Canada fuel shortage in Alberta and B.C. is costing at least one Calgary station $20,000 in potential sales.

Kiren Mjnda, who manages a Petro-Canada station in Falconridge, said until she gets a fuel shipment next week, she's predicting a substantial loss in business.

Her gas station sign is listing the price at zero to let customers know their pumps are empty.

Petro-Canada had to shut down its Edmonton refinery last week after a piece of equipment broke down, drying up the fuel supply to stations in Alberta and the B.C. Interior.

"I know it's not good," Mjnda told CBC News on Tuesday. "It's losing money, it's losing business, everything losing."

Petro-Canada spokesman Jon Hamilton said the Calgary-based company has been in communication with its retailers, but its first concern is its customers.

Petro-Canada is warning of fuel shortages because of equipment failure in its Edmonton refinery. (Karen Wade/CBC)

"Our focus right now is on getting gasoline production to return and to get product into our sites. Any other issues that we have to address we'll look at down the line," he said.

Fixing the problem at the refinery will take weeks, said Hamilton. In the meantime, Petro-Canada is relying on stocks of fuel trucked in from across Canada and overseas.

By Wednesday, about two dozen stations in Alberta and B.C. had run out of gas.

Industry analyst Michael Ervin said while there's a lack of refining capacity in North America, it wouldn't make sense for companies to build more capacity to prevent these types of shortages.

"It would be inconceivable to expect any refiner to have multimillions of dollars of extra plant sitting idle to await those rare occurrences," he said.

Petro-Canada said some stations are offering higher grade fuels at lower grade prices if there are no other options available.