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Somewhere in the upper ranges of the stack are the components of gasoline. There are between 10 and 15 different blend stocks, each with a different octane rating, which are mixed together to make gasoline.

The crude oil being used and little else determine the amount of each blend stock available for mixing. Generally, if you just dump all the blend stocks into a bucket, you end up with something around 88 or 89 octane. If you're selective and only mix the good stuff, you can make 92, 93 or even 95 octane. But once you take out the good stuff, you're left with crap-something like 85 octane. Then you have to leave enough good stuff in the bucket to bring this pee-water up to at least 87 octane. This limits the amount of 95-octane gas you can make. If you make 93-octane premium instead, you use up less of the high-octane stocks, allowing you to make a higher proportion of premium fuel.

In the Midwest, where an extensive customer base of good old boys in pickup trucks consume vast quantities of 87 octane, demand for premium fuel is low enough to make genuine high-octane premium.

In California, however, Lexus-driving executives suck down premium fuel like it's Evian, so 92 was the rule.

California refineries to ship lower octane gasoline
Nevada motorists don't have much choice

By MICHAEL SQUIRES
REVIEW-JOURNAL


Premium grade gasoline will lose a bit of its luster later this week.

Beginning Thursday, the California refineries that supply more than 90 percent of the fuel consumed in Nevada will cut the octane level of the premium and midgrade gasoline they manufacture. Premium grade gasoline sold in Nevada will drop to 91 octane from 92, while mid-grade will drop to 88.5 from 89. The lowest grade gasoline will continue to be 87 octane.

Octane is a measure of gasoline's ability to resist the knocking, rattling or pinging caused by the premature combustion of the mixture of fuel and air in an engine's cylinders.

"The individual refiners determined they wanted to send 91 octane instead of 92 ... and subsequently the pipeline changed its specifications for what it was going to ship," said Jason Geddes, senior petroleum chemist for the Nevada Department of Agriculture. "We don't have much of a choice."

Officials gave several reasons for the change.

One is California's looming ban on the gasoline additive MTBE, methyl tertiary butyl ether.

The octane enhancing chemical has been added to gasoline for years to reduce tailpipe emissions. But when it was discovered the suspected carcinogen was leaking from underground gasoline storage systems and finding its way into drinking water supplies, California officials moved to ban it.

Nevada has avoided the MTBE controversy by using ethanol to cut smog during winter months. California plans to begin using ethanol when it bans MTBE in 2003.

With that ban a little over a year away, some refiners were concerned that continuing to produce 92 octane fuel using ethanol instead of MTBE would be more expensive. Some believed it could reduce production by as much as 12 percent and possibly lead to shortages.

"The removal of MTBE is going to decrease our volumes," Keith said. "We're hoping to recoup some of that by going to 91 octane."

Another reason for the switch is the refiners' use of a common pipeline to ship fuel to Nevada, making a uniform octane standard a necessity. Kinder Morgan Energy Partners, which operates the pipeline that transports fuel to Southern Nevada from California, polled refineries and a majority favored adopting a lower standard octane in the premium and midgrade gasoline.

"It came down to we all go or none of us go," said Carolin Keith, spokeswoman for ExxonMobile.

California gas stations began selling the lower octane fuel in August. The switch triggered complaints from some motorists, who say the lower octane decreases their engine's power and mileage.

Although most of the gasoline sold in Nevada is the lowest grade, which will remain unchanged, opinions are mixed about whether Nevadans that pay for the higher grades of gasoline will notice a difference after they drive on their first tank of the lower octane gasoline.

"I'm told we're not going to see any effect in the performance characteristics or gas mileage," said Peter Krueger, executive director of Western Petroleum Marketers Association, a trade association for gas station operators.

Car dealers and mechanics agree that's probably true for most motorists. The fuel injectors on most vehicles are programmed to compensate for lower octane gasoline.

"The less sophisticated the engine, the less they'll notice," said Greg Young, owner of Silver State Motorcar Corp., a shop which provides service and repair for imports.

But owners of some European imports, such as Audi, Volkswagen and Porsche, and vehicles with carburetors and high-performance engines, might see the performance of their vehicles suffer.

"Cars that are 10 and 15 years old and were designed for what used to be premium are already suffering with the gas out there today," Young said. "For them this is a very bad thing."

Al Alley, assistant service manager at Desert Audi, said the lower octane gasoline may cause poorer performance and mileage, especially during summer months, but it won't damage their engines.

"They recommend 92 octane," he said. "Require is one thing, recommend is another.

"I bet 97 percent won't even notice. The few that notice are the people that are…