Summer’s here, and so is summer gasoline.
The pricier blend, which Canadians buy for about five months a year, replaces some of the fuel’s butane with alkylates. It reduces emissions and is better for the environment and your car.
And because of this, if you’re using premium gasoline in an older car that’s past its warranty, you probably only need regular gas during the summer. If you’re using it in a performance car, your engine probably only needs it to create extra power, and your engine is unlikely to be damaged by using lower octane fuel.
(Some vehicles recognize this by “recommending” higher octane gasoline be used, while others “require” higher octane. If your car requires it, you may void your warranty by using lower-grade fuel, though it’s doubtful the regular grade will cause any harm to your engine.)
The higher levels of butane in winter gasoline help engines start in cold temperatures. In hot weather, the butane evaporates more quickly when it is emitted as exhaust vapour and it can produce ground-level ozone that contributes to smog.
The alkylates in summer gasoline, however, are expensive to produce and they’re becoming more costly. Demand has grown from other countries, including China and India, that are strengthening their laws for vehicle emissions.
“Alkylation of gasoline for enhancing octane rating has been well practised in petroleum industries,” says Hua Song, a professor in the department of chemical and petroleum engineering at the University of Calgary. “During this process, gasoline molecules are structurally reformed under certain temperature and pressure with a suitable catalyst in place to generate highly branched ones which burn more smoothly and resist knocking better in gasoline engines, leading to more efficient combustion.”
This means you probably don’t need the expensive premium fuel you might have been using, saving you money and hurting gas stations’ profits.
The price of gas one day in late June at a Shell station in Cobourg, Ont. shows a difference of more than 50 cents between regular and premium.The Globe and Mail
While the advertised pricing of regular gasoline is highly competitive, the pricing of premium gasoline is not, because it isn’t usually advertised on the station’s signboard. A quick survey of the seven gas stations near Cobourg, Ont., showed all seven were within a penny of each other for regular gas, at about $1.30 a litre in late June, but the price for premium fluctuated wildly, even between stations within sight of each other.
The price of gas one day in late June at an Esso station in Cobourg, Ont. shows a difference of almost 40 cents between regular and premium.The Globe and Mail
Pioneer and Canadian Tire were the cheapest that day for premium, 91-octane fuel, at $1.579 per litre, or about 27 cents above the price of their regular gas. Two Petro-Canada stations – one at each exit of Highway 401, sold premium for $1.629 and $1.689, though regular was the same price. An Esso station was $1.693, and by far the most expensive was Shell, at $1.839 per litre. That was a difference of 52.6 cents a litre above its regular fuel.
The price of gas one day in late June at a Petro-Canada station in Cobourg, Ont.The Globe and Mail
The price of mid-grade, 89-octane fuel held even more of a profit margin. The gasoline is a 50/50 mixture of 87 and 91 octane, blended at the pump, so it should be priced halfway between the two. That was the case at some stations, but at Shell, Petro-Canada and Pioneer, it was only about 10 cents cheaper than premium fuel and at least 20 cents more expensive than regular.
“The difference in the rack price between regular and premium – the cost of actual production – should be about seven or eight cents a litre,” says Dan McTeague, president of Canadians for Affordable Energy, which advocates for government policies in support of cheaper oil, gas and electricity. The rack price is the wholesale market price from the refinery that fuel suppliers charge to gas stations on any given day.
In Atlantic Canada, the price of gasoline is regulated by the provincial governments and the difference between the grades is considerably smaller. In the rest of Canada, there is no price regulation and it is determined by the market itself.
The rack price varies daily and by location. Petro-Canada shows its rack prices on its public website, which is the price charged to stations before federal and provincial taxes, and the difference between regular and premium is often up to almost 20 cents, but it demonstrates that profits are much greater for the higher octane fuel.
The profits are needed because fierce competition at the pumps means regular gas is often sold at or even below cost.
“There’s no such thing as a free lunch with gas stations,” says McTeague. “The game is that they’re able to cross-subsidize the losses of selling you regular (gas) by picking it up with what you buy in-store or by selling you premium (gas). They often use premium as the cash cow to offset the losses. I guess they think that people driving premium have a lot of money to throw around.”
The ratio of sales in Canada between the two grades of fuel is about one litre sold of premium for every eight litres sold of regular gasoline, according to Kalibrate Canada Inc., which monitors more than 7,000 gas stations across the country to provide data and analytics to the petroleum industry. In 2024, 10.8 per cent of all retail gasoline sales was 91-octane, which was an increase from 9.6 per cent in 2014.
Premium fuel is usually recommended for older vehicles to prevent the damage caused by abnormal combustion, or “engine knock.” However, the computerized ignition systems in today’s engines can usually compensate for this, and especially with the additional alkylates of summer fuel.
The turbochargers of modern engines often benefit from higher octane fuel and will create more power with premium gas, though the difference is sometimes negligible. The 577-horsepower Mercedes-AMG GT63 Coupe, for example, is designed to run best on premium fuel, but if it was filled with 87-octane gasoline, “it’s a four-litre V8 and there’s enough power left, so I think you wouldn’t realize it,” says Rene Szczepek, the head of vehicle dynamics for Mercedes-AMG, based in Germany. “We are continuously calculating and looking at what’s going on in the burning zone. It’s very complex, but we’re taking care of it,” so there is no damage.
A Mercedes-AMG GT63 coupe at a gas station in Spain.Mark Richardson/The Globe and Mail
“If you go to push the car and you heat up the engine to a maximum, and all the turbines of the turbos are pushing and pushing air, and they are glowing, then that’s one thing. But if you just go to commute from A to B, and you drive on a highway at 100 kilometres an hour, then the engine is laughing about it, because the turbines are not even being used.”
The Mazda CX-70 mild hybrid has a 3.3-litre turbocharged engine that creates 319 horsepower with 87-octane fuel, but that is boosted to 340 horsepower with 93-octane fuel.
Mazda's new CX-70 comes with either a mild hybrid engine or as a plug-in hybrid.Mark Richardson/The Globe and Mail
And the Lexus RX uses an almost identical 2.4-litre turbocharged engine to the Toyota Highlander, but creates 11 more horsepower with the use of premium fuel. Lexus Canada says the RX requires premium fuel for its warranty to be valid, while the Highlander is content with less expensive regular fuel. Toyota Canada spokesperson Romaric Lartilleux acknowledges this is to provide the “Lexus driving experience” and not to protect the engine.
Is the price worth it to you, for that occasional extra possibility of performance? It’s your choice to make, but the extra cost is probably not justified – and especially if you buy your premium gasoline at the Shell station in Cobourg.