California drivers are once again dealing with gasoline above $6 per gallon, while diesel prices have reached record statewide levels. For households considering an electric vehicle, those fuel prices create another reason to think about rooftop solar as part of a broader home-energy plan.
Solar cannot lower the price displayed at the gas station.
But an electric vehicle changes the type of energy a household uses for transportation.
Instead of purchasing gasoline for every mile driven, an EV uses electricity. When a home has rooftop solar, some of that electricity can potentially be produced at the property.
That creates a connection between two expenses that homeowners have traditionally treated separately: the home electric bill and transportation fuel.
California Gasoline Is Above $6 per Gallon Again
As of September 20, 2026, AAA reported a California statewide average of approximately $6.15 per gallon for regular gasoline.
The statewide diesel average reached approximately $8.42 per gallon, which AAA listed as the highest recorded average for California diesel.
One year earlier, California regular gasoline averaged approximately $4.66 per gallon.
Certain metropolitan areas were even higher.
AAA reported San Francisco averages of approximately $6.33 per gallon for regular gasoline and $8.89 per gallon for diesel on September 20.
Current prices can be checked through AAA's California fuel-price data .
Gas prices can move quickly. The numbers above are a September 2026 snapshot, not a prediction of what California gasoline will cost next month or next year.
Why Are Fuel Prices So Volatile Right Now?
Retail gasoline prices depend on multiple factors, including crude-oil prices, refining, transportation, inventories, taxes and regional fuel-market conditions.
AAA reported on September 17 that crude oil was averaging around $100 per barrel amid continued volatility involving the Strait of Hormuz.
That kind of global oil-market movement can reach household budgets through gasoline and diesel prices even though individual homeowners have no influence over crude-oil markets.
Record Diesel Prices Can Reach Household Budgets Too
Diesel affects more than drivers who own diesel vehicles.
Trucks and other commercial vehicles use diesel to move food, building materials, consumer goods and other products throughout California.
When fuel costs rise, transportation companies face higher operating expenses.
How much of those costs eventually reaches consumers depends on freight contracts, competition, supply chains and individual businesses, so a specific retail-price increase cannot be assumed.
But high diesel prices add another source of cost pressure to an already expensive California energy market.
What Does Rooftop Solar Have to Do With Gasoline?
For a gasoline vehicle, transportation energy comes from the gas station.
For an electric vehicle, transportation energy comes from electricity.
That electricity might come from:
- the utility grid
- workplace charging
- public charging stations
- rooftop solar
- or a combination of those sources
A homeowner with rooftop solar therefore has an option a gasoline driver does not: producing part of the energy used for transportation at home.
The basic energy path can be:
Sunlight → Rooftop Solar → Home Electrical System → EV Charger → Electric Vehicle
How Much Does Driving an EV Cost Compared With Gasoline?
California's DriveClean program publishes a simple comparison of transportation energy costs.
| Energy Source | Example Cost | Estimated Cost per 100 Miles |
|---|---|---|
| Home EV Charging | About $0.26/kWh on a TOU rate | About $7 |
| Public Level 2 EV Charging | About $0.30/kWh | About $8 |
| DC Fast Charging | About $0.40–$0.50/kWh | About $11 |
| Gasoline Vehicle | 25 mpg at $5/gallon | About $20 |
DriveClean's gasoline comparison uses $5 per gallon.
California's September 2026 statewide average is currently above $6 per gallon, so the same 25-mpg gasoline vehicle would cost more per 100 miles at today's statewide average than it does in DriveClean's $5-per-gallon example.
Actual EV charging cost depends on vehicle efficiency, utility rate plan, charger losses, when the vehicle is charged and whether some charging energy comes from rooftop solar.
Solar Does Not Make EV Charging Automatically Free
This distinction matters.
Sunshine itself does not carry a retail fuel price, but installing and financing a solar system costs money.
Electricity generated by rooftop solar therefore should not be described as unlimited free transportation fuel.
The financial benefit comes from using electricity produced by a system the homeowner has installed instead of purchasing the same amount of electricity from the utility or buying gasoline for a conventional vehicle.
How favorable that comparison is depends on system price, financing, solar production, driving mileage, utility rates and the EV being charged.
California Drivers Are Already Moving Toward Electric Vehicles
Electric transportation is already a meaningful part of California's vehicle market.
The California Energy Commission reported that zero-emission vehicles represented 19.1% of new California vehicle sales during the second quarter of 2026.
Battery-electric vehicles alone represented 16.6% of new vehicle sales.
For homeowners who already own an EV, or expect to buy one during the life of their solar system, that future charging load should be considered before the solar array is sized.
NationPro USA also covers the connection between EV adoption and household electricity demand in its guide to EVs, electricity demand and residential solar .
Your Future EV Should Be Included in the Solar Design
A common solar-design mistake is sizing a system only around the electricity the home uses today.
That can become a problem if the homeowner adds an EV later.
Vehicle charging creates a new household electrical load.
Before a system is designed, homeowners should discuss:
- current annual electricity usage
- annual driving mileage
- the EV model being considered
- expected charging location
- home Level 2 charger plans
- utility EV or Time-of-Use rates
- daytime versus overnight charging
- future battery storage
- other planned electrical loads such as heat pumps
NationPro USA's guide to things to know before going solar covers future electricity loads as part of proper system planning.
Charging Your EV While Solar Is Producing Can Matter
Solar production is normally strongest during daylight hours.
If an EV is at home and charging while the solar system is producing, part of that charging load can potentially be served directly by rooftop generation.
That can reduce the amount of electricity the home needs to buy from the grid during that charging session.
The actual amount depends on:
- solar production at that moment
- the home's other electrical loads
- charger power
- vehicle charging rate
- system size
- weather
- utility metering and rate rules
What If the EV Charges at Night?
Many drivers arrive home after work and charge overnight.
Rooftop panels are not producing electricity at night.
In that situation, the vehicle normally charges using electricity from the grid unless another stored-energy source is available.
This does not automatically make overnight charging expensive.
Many California utilities offer Time-of-Use or EV rate plans where overnight electricity can cost less than electricity during evening peak periods.
Homeowners should compare the utility's actual EV rate with other available residential rate plans before changing tariffs.
Do You Need a Home Battery to Charge an EV With Solar?
No.
An EV can use rooftop solar electricity directly when charging occurs while sufficient solar power is available.
A stationary home battery adds flexibility, but it serves a different purpose.
Battery storage can help a household:
- store daytime solar for later household use
- reduce selected peak-period grid purchases
- increase solar self-consumption
- provide backup power when configured for outages
Charging a large EV battery from a smaller stationary home battery can also drain the home battery quickly.
For that reason, a homeowner should decide whether the stationary battery's priority is outage backup, peak-rate management, solar self-consumption, EV charging or a combination of those goals.
Learn more in NationPro USA's guide to home battery storage and solar energy .
Solar, Battery Storage and an EV Can Work as One Energy Plan
A modern home can contain several large electrical loads and energy resources.
Instead of planning each one separately, homeowners can consider how they work together.
| Technology | Role in the Home Energy System |
|---|---|
| Rooftop Solar | Produces electricity during daylight hours. |
| Home Battery | Stores electricity for later household use and may provide backup power. |
| Electric Vehicle | Uses electricity instead of gasoline for transportation. |
| Smart / Level 2 EV Charger | Allows faster home charging and may support scheduled charging. |
| Utility Rate Plan | Determines what imported electricity costs at different times. |
California Electricity Prices Matter Too
Switching from gasoline to an EV does not eliminate energy cost.
It changes the energy source from gasoline to electricity.
California households therefore need to look at both gasoline prices and electricity prices.
NationPro USA's current California electricity-rate guide explains how residential rates vary across PG&E, Southern California Edison and San Diego Gas & Electric.
An EV owner should also check whether the utility provides a special EV or overnight charging rate.
California's Solar Billing Rules Affect the Best Charging Strategy
New solar customers of PG&E, Southern California Edison and San Diego Gas & Electric generally operate under California's Net Billing Tariff.
Under that structure, electricity used directly by the home can offset electricity that otherwise would have been purchased from the utility.
Excess solar exported to the grid is generally credited at a rate below the retail electricity rate, although export values vary by hour.
For an EV owner, this creates another question:
When possible, is it more useful to consume available solar electricity at home rather than exporting it and purchasing electricity back later?
The answer depends on the utility, rate plan, charging schedule, export value, household load and battery configuration.
Solar Can Reduce Exposure to Two Different Energy Markets
A household with a gasoline vehicle and no solar purchases energy from two primary outside sources.
It buys electricity from the utility for the home and gasoline from fuel retailers for transportation.
With an EV and rooftop solar, part of the transportation energy requirement can move onto the home's electrical system, where some electricity can potentially be produced by the rooftop array.
That does not eliminate outside energy purchases.
But it can reduce how much household energy must be purchased from outside suppliers.
NationPro USA discusses this broader approach in its home energy-control guide .
Gas Prices Can Change Quickly, So Do Not Base a 25-Year Solar Decision on One Week
California's current fuel prices make solar-plus-EV planning timely, but homeowners should avoid assuming gasoline will remain at today's level for decades.
Gasoline can rise or fall quickly.
The better approach is to review multiple scenarios.
A homeowner can compare:
- current annual gasoline spending
- annual mileage
- vehicle fuel economy
- EV efficiency
- current utility charging rate
- expected solar production
- solar system cost
- EV charger cost
- battery-storage cost where applicable
- expected length of homeownership
A long-term energy decision should work under reasonable assumptions rather than relying on one unusually high gasoline-price period.
The Former 30% Homeowner Solar Tax Credit Should Not Be Included in a 2026 Purchase
California homeowners evaluating solar in 2026 should also remember that the former federal Section 25D homeowner credit ended after 2025.
The system should therefore be evaluated using the actual 2026 purchase or financing structure rather than an outdated net price that subtracts the former homeowner credit.
NationPro USA explains the change in its California solar guide after the federal tax credit .
Questions EV Owners Should Ask Before Installing Solar
If an EV is already in the driveway or likely to be purchased soon, ask:
- How many miles do I drive each year?
- How efficient is my current or planned EV?
- How much extra annual electricity will charging require?
- Will most charging happen during the day or overnight?
- Does my utility offer an EV charging rate?
- Can my electrical panel support a Level 2 charger?
- Should the solar array be sized for the EV load now?
- Would battery storage serve a useful purpose for my home?
- Do I want outage backup?
- What will the entire solar, battery and charging setup cost?
Solar Is Becoming Part of a Broader Household Energy Strategy
Residential solar has traditionally been discussed as a way to reduce an electric bill.
Electric vehicles make the calculation broader.
Electricity can now power the home, air conditioning, appliances and transportation.
That means a properly designed rooftop solar system can potentially serve more of the household's total energy demand than it did when every vehicle in the driveway burned gasoline.
The goal is not to promise that solar eliminates gasoline costs, electric bills or all dependence on the grid.
The goal is to determine how much electricity a household can reasonably produce and use at home and whether the economics make sense.
Solar EV Charging FAQs
Can I charge an electric vehicle with rooftop solar?
Yes. When an EV is connected to the home's electrical system while rooftop solar is producing, available solar generation can serve part or all of the charging load depending on solar output, home consumption and charger demand.
How much is California gasoline in September 2026?
AAA reported a California statewide average of approximately $6.15 per gallon for regular gasoline on September 20, 2026. Fuel prices change frequently, so homeowners should check current pricing when making comparisons.
How much does it cost to drive an EV 100 miles in California?
California DriveClean currently estimates approximately $7 per 100 miles for home charging using an example Time-of-Use electricity price of about $0.26 per kWh. Actual cost depends on vehicle efficiency and the homeowner's electricity rate.
How does that compare with a gasoline vehicle?
DriveClean estimates about $20 per 100 miles for a 25-mpg vehicle when gasoline costs $5 per gallon. California's September 2026 statewide gasoline average is currently above $6, so actual gasoline cost under the same fuel-economy assumption would be higher than that example.
Do I need a battery to charge my EV with solar?
No. An EV can consume rooftop solar directly while the panels are producing. Battery storage can add flexibility for household energy use, peak-rate management and backup power, but it is not required for solar EV charging.
Can solar charge my EV at night?
Rooftop panels do not produce electricity at night. Overnight EV charging normally uses grid electricity unless stored energy is available. Some utilities offer lower overnight EV or Time-of-Use rates.
Should my solar installer know that I plan to buy an EV?
Yes. An EV can materially increase household electricity consumption. Future EV charging should be included when reviewing system size, electrical service and expected solar production.
Does a home battery make EV charging cheaper?
Not automatically. A stationary battery can shift when electricity is used, but battery cost, capacity, efficiency, utility rates and backup priorities all matter. In some cases, daytime solar charging or low-cost overnight utility charging may be a better use of available energy.
Are electric vehicles becoming more common in California?
Yes. California Energy Commission data shows zero-emission vehicles represented 19.1% of new California vehicle sales in the second quarter of 2026, with battery-electric vehicles representing 16.6%.
See How Solar Could Power More Than Your Home
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