The reason for the price discrepancy between 91 octane gasoline and premium gasolines is a mystery, according to the Automobile Association.

It’s been more than a month since gas stations were required to advertise premium gas prices to help improve competition, and nothing has changed, said senior AA policy adviser Terry Collins .

Seven complaints have been filed with the Commerce Commission about possible non-compliance with the new rules, including not displaying all prices, prices too small to read, no price displayed and the price displayed not matching the price charged.

Collins noted that the period had been volatile in global markets, but motorists were still paying about 15 to 16 cents per liter more than they should have. “We welcome oil companies that justify the price difference as it is still a mystery to us.”

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Currently, the average price of 91 is up 5.5% over the past 28 days to $2.82 per liter, according to the Gaspy app Wednesday afternoon.

The average price of 95 octane rose 7.3% to $3.01 and that of 98 octane rose 9.9% to $3.19.

It's been a little over a month since petrol stations were required to announce the price of premium petrol.

WARWICK SMITH / Stuff

It’s been a little over a month since petrol stations were required to announce the price of premium petrol.

Gasoline prices jumped well above $3 a liter after Russia invaded Ukraine on Feb. 24, and have since fallen, following international oil prices and temporary duty cuts tax on fuel by the government.

Premium gasoline, which has sold at higher prices and higher margins than regular gasoline, has contributed to high industry profitability, the Commerce Commission said in its 2019 report on the gasoline sector. retail fuels.

The extra margin made by oil companies does not appear to reflect actual cost differences, the commission said. The lack of premium gasoline prices displayed on price boards made it difficult for consumers to compare prices, which contributed to higher margins.

“I haven’t yet seen a significant change in margins as a result of these price panels going up,” Collins said.

“I know it’s only been a month and I know it’s been extremely volatile, but from what I’ve seen in margins and price differences a year ago, they’re still at pretty much the same.”

He said the AA never received a satisfactory response from the fuel industry regarding the price difference between 91, 95 and 98. It may contain additives, but the cost of those additives was not reflected. in the prices currently charged, he said.

The infrastructure was the same for 91 and premium. But a difference of about 3 or 4 cents in the landed price, before markups and taxes were added, ended up being an extra 15 to 16 cents at the pump, and that went up to 20 cents, Collins said. .

“Collectively, it’s about 15 to 16 cents more expensive than we think,” he said.

Late model cars with high compression engines had to use higher octane fuel. The lower the octane rating, such as diesel, the more likely the fuel is to ignite under compression, causing “knocking”.

Department for Business, Innovation and Employment (MBIE) data for December showed around two-thirds of imported fuel was 91 and just over a third premium, although levels fluctuate.

Motorists will not yet feel the full impact of changes to regulate the fuel market, according to the Commerce Commission.

Alden Williams / Stuff

Motorists will not yet feel the full impact of changes to regulate the fuel market, according to the Commerce Commission.

Z did not stock 98, spokeswoman Kiri Shannon said, but it did sell 95 octane.

“Higher octane fuels are more expensive due to their higher fixed costs relative to lower volume – meaning they are more expensive to produce due to higher processing and distillation requirements .”

The data provided by the Commerce Commission is from 2019, and there has been “significant market volatility” in the cost of fuel since then, she said.

Motor Trade Association energy and environment sector manager Ian Baggott said most of the price difference could be explained by the lower amount of octane gasoline high sold. There was some cost, like a dedicated underground reservoir.

“It’s low volume and service stations have to decide if they choose to stock it. They will either do so based on their understanding of the local market. It is mainly the higher performance European vehicles that use higher octane fuel.

Some members of the MTA gas station said customers appreciated being able to see the full range of prices on different fuels, although some customers found the additional information confusing, he said.

The gap between 91 gasoline and premium gasoline would remain until other vehicles entering the fleet required an octane rating of 95 or higher.

A spokeswoman for the Commerce Commission said the full effect of changes to regulate the fuel market would not yet be felt at the retail level.

From July, fuel wholesalers and distributors were required to provide information to help the commission monitor and report on the competitive performance of the fuel market. The price difference between 91 octane and premium fuel can be included, she said.