Many gas stations in Nova Scotia were still low or out of gas Saturday. CBC

It's one of the peak weekends for fuel demand, and many Nova Scotia gas stations are out of premium or diesel because of a Dartmouth refinery power outage.

On Friday evening, many stations were out of regular gas, but most got deliveries overnight or Saturday morning.

The Imperial Oil refinery in Dartmouth has been offline since a thunderstorm July 21 shut off power at the plant. The refinery normally supplies diesel and gasoline to all types of service stations in Nova Scotia.

To minimize further disruptions, the refinery stayed closed while the company moved up its annual maintenance shutdown, which had been planned for early next month.

Some stations are on allocation, which means they are only allowed to sell a certain volume of fuel each day despite consumer demand.

"When there are pressures on inventory, we work with our customers to ensure they are all treated fairly and they have regular and controlled access to refined products at our loading rack," said Imperial Oil spokesman Merle MacIssac.

"That means you don't give unlimited amounts to any one company whose getting product from the refinery."

Demand is high this weekend because of the final date of the U2 360 tour putting thousands of fans on the road to Moncton. The Sappyfest music festival is also underway in Sackville, N.B., in addition to a bluegrass festival in Bible Hill, N.S.

Demand higher on long weekends

Halifax-based oil and gas consultant Bill Simpkins said it's the public reaction to news of the potential shortage, coupled with long weekend demand, that has created the problem. He expects it to be short-lived.

"There might be some pumps that you can't get the fuel that you generally are looking for, but generally you will not experience any widespread supply outages," he said.

"After this weekend, probably even today, you'll find that retailers are being supplied and there should be product available."

In the meantime, if you don't have to top up your tank this weekend, don't, Simpkins advised.

"All retailers will prepare for demand," he said. "They know long weekends in particular, people will be out driving, so demand is higher on long weekends.

"And if there's any concern raised in people's mind that there might be difficulties getting product, going out and filling up your tank will only make it worse."

Delays at toll station

However, many of the gas stations that had low volumes or were out of gas were along Highway 102, the main route between New Brunswick and Nova Scotia.

Imperial Oil said Saturday more supply has been brought in that is adequate to supply retailers for this time of year.

Nova Scotians heading out of town were also met with delays as they reached the Cobequid Pass toll station in the Wentworth Valley.

Traffic was backed up several kilometres late Saturday morning, the CBC's Brian Dubreuil reported.

Dubreuil said officials at the toll station were waving cars through without paying the toll to relieve some of the backlog of vehicles.

The Cobequid Pass cleared up by early afternoon.