"Oh, It's The Alkylate's Fault..."

Experts are predicting pump prices, which jumped by almost a dollar a gallon in each of the last two springs in many parts of the United States, will spike again this year as refiners and gas stations switch from winter- to summer-blended fuels.

The increases, starting as early as February in southern California, could push the average national price to a record $3.50 a gallon or more by June. Prices in urban areas on each coast could approach $4 a gallon.

And the reason for the spring price shocks? Analysts say it’s linked to a shortage of alkylate, a little-known and expensive gasoline additive that some in the industry are calling “liquid gold.”

It has become a must-have ingredient since refiners stopped using MTBE two years ago when the potentially cancer-causing additive was found to be seeping into ground water.

The alkylate shortage has become the most important driver of summer gas prices, said Doug Leggate, an analyst at Citigroup Global Markets. “Supply of (alkylate) will set the price of summer gasoline — not inventory levels,” he said.

Oil companies deny they are purposely limiting production of alkylate, which like gasoline, jet fuel, and asphalt is a by-product of the oil refining process. But only recently have some started studying how they can boost output, and alkylate prices today are more than 15 percent higher than spot gasoline prices.

That means overall costs will jump when it is added in larger quantities to summer-blend fuels.

Without additives, gasoline doesn’t burn completely, increasing tailpipe air pollution. And untreated gas evaporates more quickly in hot weather, potentially causing vapor lock when it changes from a liquid to a gas and blocks fuel lines.

The federal government long ago required refiners to boost the oxygen content of summer-blend gasoline to make it burn more completely, a problem that was solved by adding MTBE and, more recently, ethanol.

But ethanol also has a high evaporation rate, so refiners increasingly have turned to alkylate, which Tom Kloza, publisher and chief oil analyst at the Oil Price Information Service in Wall, N.J., calls the “magic bullet” in making summer gasoline.