California Fuel Blends: Time for a Change?
California Fuel Blends: Time for a Change?
March 14, 2026 • LodiEye
Summary
California's boutique gasoline blend—CARBOB—was designed decades ago to fight the state's severe smog crisis, and it worked. But the system built around that fuel is now breaking down. Two major refinery closures have eliminated 20% of the state's refining capacity in under a year. Prices at the pump have surged past $5.34 per gallon while neighboring states pay $1.00 to $1.80 less for gasoline refined from the same crude oil. Analysts warn of $7–8 gas by summer. This report examines how California got here, why the current system is failing, and evaluates four alternatives—from modest tweaks to a fundamental rethinking of the state's fuel policy.
How California Got Here
California was granted a unique waiver under the 1970 U.S. Clean Air Act, allowing it to set emissions standards stricter than the federal government. The California Air Resources Board (CARB) used that authority to develop California Reformulated Gasoline (CaRFG), phased in through the 1990s. The current specification—CARBOB (California Reformulated Blendstock for Oxygenate Blending)—took full effect in 2003, requiring very low aromatics, low sulfur, and a Reid Vapor Pressure (RVP) as low as 7.0 psi in summer, making it the cleanest-burning gasoline in the world.
CARB's 2003 assessment found that CaRFG provided emission reductions equivalent to removing 3.5 million vehicles from California's roads. In practical terms, it helped make the mountains visible again from Los Angeles. The environmental achievement is real. But that achievement came with structural consequences that are now compounding into a crisis.
The Price of Being an Island
CARBOB is produced almost exclusively by California refineries—over 90% of demand is met in-state. Out-of-state refineries can produce it, but will only do so when the price premium makes it worthwhile. This creates what energy analysts call a “fuel island”: California is effectively cut off from the national gasoline supply network.
When a refinery goes offline in Texas, conventional gasoline can be sourced from dozens of alternative refineries within days via an extensive pipeline network. When a California refinery goes offline, replacement CARBOB must be imported as blending components from Asia and assembled in-state—a process that takes a minimum of three weeks by ship. During that gap, prices spike as distributors compete for dwindling supply.
The Breakthrough Institute has identified two distinct costs of the CARBOB requirement: a direct production premium of roughly 18 cents per gallon in additional refining expense, and the far more damaging market isolation effect that amplifies every supply disruption into a consumer price spike. On top of that, UC Berkeley economist Severin Borenstein has documented a persistent “Mystery Gasoline Surcharge” averaging around 50 cents per gallon since 2015—a structural retail premium enabled by market concentration and the tight supply conditions CARBOB creates.
What Californians Pay For: Fuel Cost Components (Estimated ¢/gal)
A System Under Collapse
The fuel island problem has escalated from a structural inconvenience to an acute crisis. Phillips 66 shuttered its Los Angeles refinery in October 2025, removing 139,000 barrels per day of capacity. Valero ceased operations at its Benicia facility in January 2026, taking another 145,000 barrels per day offline. Together, these closures eliminated roughly 20% of California's total refining capacity in under six months.
California is now projected to have just 11 operating refineries by the end of 2026—down from 42 four decades ago. The remaining capacity is concentrated among just three companies: Chevron, Marathon, and PBF, which together control over 90% of the state's CARBOB production. USC professor Michael Mische has projected that gasoline could reach $8.45 per gallon if these supply constraints persist into peak summer driving season.
Right Now: As of March 11, 2026, California's average regular gasoline price is approximately $5.34 per gallon. Arizona is $4.02. Oregon is $4.29. Nevada is $4.36. The national average is $3.54. Lodi-area drivers are paying the highest fuel prices in the continental United States for gasoline refined from the same global crude oil. Track current prices at Lodi411.com/fuel-prices.
Gas Prices Across Western States (March 2026)
What California’s Neighbors Actually Use
California exists in PADD 5 (Petroleum Administration for Defense District 5) alongside Arizona, Nevada, Oregon, Washington, Alaska, and Hawaii. Despite sharing a regional fuel market, these states use significantly different gasoline formulations:
| State | Gasoline Type | Summer RVP | Key Characteristic |
|---|---|---|---|
| California | CARBOB (unique boutique blend) | ~7.0 psi | Strictest spec in nation; produced almost exclusively in-state |
| Arizona (Maricopa) | AZRBOB (modified CA Phase 2) | ~7.0 psi (summer) | Simpler than CARBOB; sourced from CA refineries & TX pipeline |
| Nevada | Conventional (CBOB) | ~9.0 psi | Easy to produce; any refinery can supply |
| Oregon | Conventional / Federal RFG | ~7.8–9.0 psi | Supplied by WA refineries and CA exports |
| Washington | Conventional / Federal RFG | ~7.8–9.0 psi | Five in-state refineries; pipeline to OR |
The common thread: none of California's neighbors require anything as complex or restrictive as CARBOB. Nevada uses conventional gasoline that is easy to produce and doesn’t require stringent specifications. Arizona uses AZRBOB in the Phoenix metro area—a modified version of California's older Phase 2 specification that is simpler and cheaper to produce. Oregon and Washington use standard RBOB or conventional blends supplied by Washington's five refineries.
California Also Requires Two Separate Seasonal Blends
Beyond the CARBOB specification itself, California requires different formulations for summer and winter—and enforces a longer summer season (April 1 through October 31) than most states. This creates a recurring cycle of refinery shutdowns, supply gaps, and price spikes every spring.
| Characteristic | Summer Blend | Winter Blend |
|---|---|---|
| Reid Vapor Pressure | Lower (~7.0 psi in CA) | Higher (allows easier evaporation) |
| Butane Content | Lower (reduces volatility) | Higher (cheaper, aids cold starts) |
| Energy Content | ~1.7–2% higher | Slightly lower |
| Fuel Economy | Slightly better MPG | Marginally lower MPG |
| Production Cost | Higher (complex refining) | Lower (simpler process) |
| Pump Price Effect | Higher | $0.10–0.30 cheaper |
| Emissions | Lower (cleaner burning) | Higher if used in warm weather |
| CA Season | April 1 – October 31 | November 1 – March 31 |
Every spring, refineries undergo planned maintenance to retool from winter to summer production. This reduces output precisely when demand is rising, and West Coast refinery utilization can drop below 80% during the maintenance window. Prices typically jump 10–15 cents per gallon from the blend premium alone, with additional spikes of 30–50 cents or more when unplanned outages coincide with the transition. The pattern is predictable, disruptive, and entirely a product of the two-blend requirement.
Summer vs. Winter Blend: Key Differences
Four Alternatives
Given the mounting cost of California's current fuel system, four reform options merit serious consideration—ranging from incremental adjustments to fundamental restructuring.
Option A: Stay the Course + Add E15
This is the path California is currently on. Governor Newsom signed AB 30 in October 2025 authorizing the sale of E15 (gasoline with 15% ethanol), making California the last state to permit it. E15 diversifies the fuel supply by increasing the ethanol component and reducing dependence on petroleum refining.
Proponents estimate E15 could save Californians up to $2.7 billion annually and reduce pump prices by up to $0.20 per gallon. A UC Riverside study found no adverse impact on NOx emissions and a reduction in particulate emissions. However, E15 does not address the structural CARBOB isolation problem or the seasonal blend cycle. Some experts caution that expanded corn-based ethanol production carries broader environmental and land-use costs. And $0.20 per gallon barely dents a $1.80 premium over the national average.
Option B: Eliminate Winter Blend—Use Summer Blend Year-Round
By standardizing on a single CARBOB formulation year-round, California could eliminate the costly seasonal transition entirely. Refineries would no longer need planned shutdowns twice a year to retool, reducing the supply gaps and price spikes that accompany each changeover. Summer blend is the cleaner, more efficient fuel—containing roughly 1.7–2% more energy per gallon—so air quality would improve in winter months as well.
The tradeoff: consumers would lose the winter price discount of $0.10–0.30 per gallon that comes with cheaper-to-produce winter fuel. Summer blend's lower volatility could cause marginally harder starts in cold inland areas like the Central Valley and Sierra foothills, though modern fuel injection systems are far more tolerant of low-RVP fuel than older engines. Critically, this option does not solve the fuel island problem—California would still rely on the same shrinking pool of in-state refineries producing a fuel that almost no one else makes.
Option C: Adopt the Same Fuel Used by Neighboring States
This is the most impactful option and the most politically difficult. If California accepted conventional gasoline (CBOB) or standard federal reformulated gasoline (RBOB)—the same fuels used by Nevada, Oregon, Washington, and most of the country—the fuel island would effectively dissolve.
Distributors could source from any refinery in the nation. The Gulf Coast alone has over 50 refineries producing standard blends. California's own remaining refineries could increase output per barrel of crude, since CARBOB's strict specifications yield less finished gasoline per barrel than conventional processing. Marine imports of standard gasoline would face fewer compatibility issues and lower costs than importing CARBOB-specific blending components from Asia. The direct CARBOB production premium (~18¢/gal), the market-concentration surcharge (~50¢/gal), and much of the supply vulnerability would erode.
The cost: CARB has never conducted a comprehensive study of what abandoning CARBOB would mean for air quality in today's fleet of far cleaner vehicles with modern emissions controls. A 2023 study found CARBOB probably still reduces ozone pollution, though the researchers' preferred model showed no statistically significant impact—confounded by the simultaneous tightening of tailpipe standards over the same period. The political cost for any governor would be enormous, and environmental groups would vigorously oppose any rollback of fuel specifications.
Option D: Conditional CARBOB Suspension (Middle Path)
Rather than permanently abandoning CARBOB, California could adopt a trigger-based system: when the CARBOB spot price premium exceeds a defined threshold above standard RBOB—say, 30 cents per gallon—CARB would automatically authorize the sale of federal RFG in the state until prices stabilize. CARBOB would remain the default fuel; suspension would be the emergency valve.
This approach has precedent. Governor Newsom has already twice directed early transitions to winter blend during price emergencies (2022 and 2023), and CARB noted the air quality impacts were “minimal.” ABx2-3 (Gallagher) sought to formalize exactly this kind of flexibility. A conditional suspension system would preserve CARBOB's environmental benefits during normal operations while preventing the worst price spikes from cascading through a system with no relief valve.
Comparing the Options
| Factor | A: Status Quo + E15 | B: Year-Round Summer | C: Western Standard | D: Conditional Suspension |
|---|---|---|---|---|
| Estimated Price Impact | –$0.10 to –$0.20 | –$0.10 to –$0.30 (spike reduction) | –$0.50 to –$1.00+ | –$0.30 to –$0.50 (during spikes) |
| Supply Resilience | Minimal improvement | Moderate (less disruption) | Highest (national supply) | High (during emergencies) |
| Air Quality | Maintained or improved | Improved (summer spec all year) | Reduced (federal minimums) | Mostly maintained |
| Refinery Complexity | Unchanged | Simplified (one blend) | Greatly simplified | Unchanged normally; simplified in crises |
| Market Competition | Unchanged | Unchanged | Dramatically increased | Increased during spikes |
| Cold-Start Risk | None | Minor (inland areas) | None | None |
| Political Feasibility | Already enacted | Moderate | Very difficult | Moderate to high |
| Implementation Timeline | In progress (CARB rulemaking) | 1–2 years (regulatory change) | Multi-year (legislative + regulatory) | Months (executive + CARB action) |
Estimated Price Scenarios: Monthly Averages Under Each Option
What the Data Suggests
No single option is a silver bullet. E15 (Option A) is already underway but provides minimal relief against a structural premium of $1.50 or more. Year-round summer blend (Option B) would remove a predictable source of disruption but doesn't address the core isolation problem. Adopting western standard fuels (Option C) would deliver the largest consumer savings and greatest supply resilience but faces steep political and environmental headwinds. The conditional suspension approach (Option D) may be the most actionable near-term reform—preserving CARBOB as the default while providing an escape valve that prevents the worst consumer harm.
In practice, these options are not mutually exclusive. California could implement E15 (already underway), move to year-round summer blend to eliminate seasonal disruptions, and simultaneously adopt a conditional suspension trigger for periods of extreme market stress—all while studying the air quality implications of a longer-term transition away from CARBOB. The combination of B + D, layered on top of A, would meaningfully reduce both the average price and the volatility that hits California drivers hardest.
The Numbers in Context: As of March 2026, a California driver filling a 15-gallon tank weekly pays roughly $624 per year more than an Arizona driver, $546 more than an Oregon driver, and $1,404 more than a driver paying the national average—all for gasoline refined from the same global crude oil. The CARBOB specification and its cascading market effects are the single largest structural contributor to that gap.
The View from Lodi
Lodi sits roughly 75 miles from the now-shuttered Valero Benicia refinery and 90 miles from the PBF Martinez facility that suffered an explosion in February 2025. Both disruptions sent local prices soaring within days. Every spring, the seasonal blend transition adds another round of price increases that ripple through the northern San Joaquin Valley before the first warm day arrives.
If Lodi could access the same fuel sold in Reno—just 180 miles east—at Nevada's conventional gasoline prices, the typical Lodi household would save an estimated $50–80 per month at the pump. The fuel that goes into a car in Sparks, Nevada, and the fuel that goes into a car in Lodi, California, come from the same crude oil, pass through some of the same refineries, and power the same engines on the same roads. The difference is a regulatory specification written in Sacramento—one that was necessary and visionary in the 1990s, and that may now be costing Californians more than it saves.
California's air is cleaner than it was 30 years ago. Its vehicles are cleaner. Its fleet is electrifying. The question is no longer whether CARBOB was the right choice in 2003. The question is whether a fuel policy designed for an era of severe urban smog and abundant local refining capacity still makes sense in a state with 11 refineries, $5+ gasoline, and a 2035 deadline to phase out new combustion vehicles entirely.
Track current fuel prices in Lodi at Lodi411.com/fuel-prices.
Sources
- Here's why gas always costs more in California — KSBY
- Governor Newsom urges accelerated action on new gas blend to lower prices
- Growth Energy on Inclusion of E15 in California Budget
- Consumers — California Fuels + Convenience Alliance
- As California Pushes Increased Ethanol Use, Experts Sound the Alarm — Inside Climate News
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- What's the difference between winter and summer gas blends? — CBS News
- What Is the Difference Between Summer and Winter Gas? — Rislone
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- How California Regulated Itself Into an Energy Crisis — Breakthrough Institute
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- ABx2-3 (Gallagher) Fuel Blend Flexibility Bill — CA State Assembly (PDF)
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- Governor Newsom Signs Bill Expanding Fuel Options — Office of Governor
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- California Gasoline Supply to Arizona and Nevada — Stillwater Associates
- State Fuels (Boutique Fuel Programs) — U.S. EPA
- Reformulated Gasoline Program — U.S. EPA
- Arizona and Nevada Depend on California for Their Transportation Fuels — IER
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- Cleaner Burning Gasoline (CBG) — Arizona Department of Agriculture
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