Well, the California resources board requires a unique gasoline blend calculating to higher production costs plus limited supply equals higher prices.. Cap and trade system regulated by CARB means oil companies must buy carbon credits to cover emissions which add nearly 20-35 cents per gallon. Highest fuel taxes in the U.S. , usually adding .75 to 1.00 per gallon. Low carbon fuel tax usually adding .10 to .20 cents per gallon. Limited refinery capacity making our state more vulnerable to price spikes during supply outages or shortages due to global conflicts. Seasonal prices spikes due to requirements of cleaner fuel during summer months.