What a range-extended electric vehicle is

A range-extended electric vehicle (REEV) is a car that runs on a battery and electric motor most of the time, but carries a small gas engine that turns on automatically when the battery gets low. You drive it like a regular electric car for daily trips — plugging it in at home or at a charger — but the gas engine acts as a backup generator on longer drives, so you do not have to stop to charge.

The gas engine does not power the wheels directly. Instead, it generates electricity to keep the battery charged while you drive. This is different from a hybrid, where the gas engine can power the wheels on its own. In a REEV, the electric motor always drives the wheels.

The most common REEV on the market today is the BMW i3 with Range Extender, though production ended in 2024. The Chevrolet Volt (2016–2019) was also a REEV before Chevrolet discontinued it. Other manufacturers have tested the design, but few currently sell them in the United States.

Key Takeaways

  • A REEV runs on battery power for daily driving and automatically starts a small gas engine to generate electricity when the battery is low, so you do not have to charge as often on long trips.
  • Most REEV owners drive on battery power alone for 80 to 90 percent of their miles, using the gas engine only for occasional longer drives or when charging is not available.
  • REEVs cost more than comparable gas cars but less than most pure electric vehicles, and fuel and maintenance costs are lower than gas-only cars.
  • A REEV works best if you have a place to charge at home or work and make most of your trips within the battery range, typically 20 to 50 miles per charge.
  • Resale value for REEVs is uncertain because the market is small and shrinking, so you should research specific models before buying.

How the battery and gas engine work together

When you start a REEV with a full battery, the gas engine stays off. The electric motor draws power from the battery and drives the car. As you drive, the battery drains. Once the battery reaches a set level — usually around 20 to 30 percent — the gas engine starts automatically and runs a generator to produce electricity. That electricity either powers the motor directly or charges the battery, depending on the model and driving conditions.

You do not have to do anything. The car switches between battery-only and gas-engine-assisted driving on its own. If you stop and plug in before the battery is depleted, the gas engine never runs. If you keep driving without charging, the gas engine keeps the car moving until you reach a charger or gas station.

The gas tank in a REEV is small — typically 9 to 12 gallons — because it is only meant to extend your range, not be your primary fuel source. A full tank might add 100 to 150 miles of range, depending on the model. The battery itself is smaller than in a pure electric vehicle, which keeps the weight and cost down.

Daily driving and charging patterns

Most REEV owners charge at home overnight or at work during the day. The battery range is usually 20 to 50 miles, which covers the average American commute. If your daily round trip is 40 miles or less and you charge regularly, you may never use the gas engine except on road trips or when you forget to charge.

This is the main advantage of a REEV over a pure electric vehicle: you do not have to plan every trip around charging stations. You can drive 300 miles in a day without stopping to charge, as long as you are willing to use the gas engine for part of it. For someone who drives mostly locally but occasionally takes longer trips, a REEV removes the anxiety of running out of charge.

The trade-off is that you still need access to a charger. If you rent an apartment with no charging option, a REEV is not practical. You would rely on the gas engine too often, which defeats the purpose of buying an electric vehicle.

Fuel costs and maintenance compared to gas and electric cars

A REEV costs less to fuel than a gas-only car because you drive on electricity for most miles. If you charge at home, electricity typically costs one-third to one-half what gasoline costs per mile. A REEV owner who drives 12,000 miles per year and uses the gas engine for 10 percent of those miles might spend $400 to $600 per year on gas, compared to $1,200 to $1,800 for a gas-only car.

Maintenance is also lower than a gas car because the electric motor has fewer moving parts and the gas engine runs less often. You still need oil changes when the gas engine runs, but less frequently. Brake wear is reduced because the electric motor can slow the car through regenerative braking, which captures energy as you slow down.

Compared to a pure electric vehicle, a REEV costs more to fuel because you are buying both gas and electricity. However, a REEV costs less upfront than many electric vehicles, and you do not have to pay for a home charging installation if you do not want to — though having one makes the REEV much more practical.

Purchase price and available incentives

A new REEV typically costs $35,000 to $50,000, depending on the model and features. This is more than a comparable gas car but often less than a pure electric vehicle with similar range. The BMW i3 with Range Extender, for example, started around $45,000 before production ended.

Federal tax credits for electric vehicles do not cover REEVs in most cases. The federal credit of up to $7,500 is available only for vehicles that meet specific battery size and domestic content requirements, and most REEVs do not may have access to because their batteries are smaller. Some states offer their own incentives for plug-in hybrids or electric vehicles, but these vary widely and change frequently. Check your state's environmental or energy office website to see what is currently available.

Used REEVs are less expensive but come with uncertainty about battery health and resale value. Because the REEV market is small and shrinking, used prices can be unpredictable. A 2016 Chevrolet Volt might cost $12,000 to $18,000 depending on mileage and condition, but the market for these cars is thin, so selling one later may be difficult.

When a REEV makes sense for your situation

A REEV works best if you have a predictable daily commute of 50 miles or less, access to a charger at home or work, and take occasional longer trips. If you drive 100 miles every day, a REEV will use the gas engine constantly, and you would be better off with a pure electric vehicle or a gas car. If you have no place to charge, a REEV becomes an expensive gas car with a small battery.

A REEV also makes sense if you live in an area with few public charging stations but want to reduce your gas consumption. You get the benefit of electric driving for daily trips without the range anxiety of a pure electric vehicle. This is especially valuable if you live in a rural area or travel frequently to places without charging infrastructure.

A REEV does not make sense if you are looking for the lowest possible purchase price, if you drive very long distances daily, or if you want the environmental benefit of zero tailpipe emissions. For those situations, a gas car, a hybrid, or a pure electric vehicle would be a better fit.

Resale value and market availability

The REEV market in the United States is small and shrinking. The Chevrolet Volt was discontinued in 2019, and the BMW i3 with Range Extender ended production in 2024. No major manufacturer currently sells a new REEV in the U.S. market. This means resale value is uncertain, and finding a used REEV may require searching across multiple states or waiting for inventory.

Used REEV prices depend heavily on mileage, battery condition, and local demand. A well-maintained Volt or i3 with low mileage may hold value reasonably well, but you cannot count on it. Before buying a used REEV, research the specific model's reliability, battery degradation patterns, and what similar cars are selling for in your area. A mechanic familiar with electric vehicles should inspect the battery and motor before you buy.

If you are considering a REEV as a long-term investment, understand that you may have difficulty selling it later. The market is too small to predict resale value with confidence. Buy a REEV because it fits your driving needs now, not because you expect it to hold value.

Frequently Asked Questions

Can I drive a REEV on gas only if I do not want to charge?

Yes, but you would be wasting money. The gas engine can power the car indefinitely by generating electricity, but the car is heavier and less efficient than a gas-only vehicle because it carries a battery and electric motor. If you never charge, you would pay more for gas and maintenance than you would with a regular car.

How long does the battery last in a REEV?

Most REEV batteries are designed to last 8 to 10 years or 100,000 to 150,000 miles, though some last longer. Battery degradation is gradual — you lose a few miles of range per year, not a sudden failure. Replacement batteries are expensive, typically $5,000 to $15,000, so battery health is important when buying used.

What happens if the gas engine fails in a REEV?

If the gas engine breaks, you can still drive on battery power alone, just like a pure electric vehicle. You would have the range of the battery — typically 20 to 50 miles — and then you would need to charge. Repairs to the gas engine are similar to repairs on any small gas engine and are usually less expensive than electric motor repairs.

Is a REEV better for the environment than a gas car?

Yes, if you charge regularly. A REEV that is charged daily and uses the gas engine only occasionally produces fewer emissions than a gas-only car. However, a pure electric vehicle charged on renewable energy produces fewer emissions than a REEV. The environmental benefit depends on how often you charge and where your electricity comes from.

Can I tow with a REEV?

Most REEVs are not designed for towing. The BMW i3 and Chevrolet Volt have low towing capacity or none at all. If towing is important to you, a gas car, truck, or a pure electric truck would be better choices.