Understanding EREV: The Future of Extended Range Electric Vehicles

Purchasing an electric car can be a daunting experience. With numerous brands and options to evaluate for the best value, it’s easy to feel overwhelmed. An additional consideration is charging—do public chargers exist in your area? Can you charge at home? What if the answer to both questions is no? In such cases, Extended Range Electric Vehicles (EREVs) might be a viable alternative.

An EREV differs from a Plug-in Hybrid (PHEV) in that it uses a combustion engine solely as a generator. Unlike PHEVs, which connect the gas engine to the drivetrain, EREVs power the wheels exclusively through electric motors, with the engine functioning strictly to recharge the batteries when necessary.

Typically, EREVs are equipped with compact battery packs, often not exceeding 45 kWh, enough to provide a respectable electric-only driving range—some models can travel up to 200 km. Once the battery is depleted, drivers can opt to activate the generator or recharge using a DC charger.

This unique functionality allows EREVs to effectively recharge themselves when no traditional charging options are available. A 200 km range suffices for many drivers, and the onboard generator provides peace of mind for longer journeys or unexpected circumstances.

How do EREVs compare with PHEVs if both feature combustion engines? Essentially, EREVs mark an evolution of PHEVs: separating the gas engine from the drivetrain simplifies the vehicle's mechanical complexity and allows the engine to operate at optimal efficiency, further enhancing fuel savings.

EREVs typically deliver more power than PHEVs; it’s common to find EREVs with electric power outputs reaching 300 kW. They offer a more engaging driving experience, benefiting from the instant torque of electric powertrains and featuring superior electric-only driving ranges, along with compatibility with DC fast chargers.

However, one downside is size. Currently, EREVs are primarily available as larger SUVs and crossovers, as manufacturers concentrate on that segment. The long-term trend remains uncertain without broader acceptance of EREVs. Another concern is that some early EREVs may be less fuel-efficient than their PHEV counterparts, and recharging via an onboard generator can prove more costly than traditional AC or DC charging methods.

These vehicles are designed to minimize the inconveniences typically associated with battery limitations. A primary challenge hindering widespread EV adoption is inadequate charging infrastructure. EREVs alleviate this issue, offering up to 1,200 km of electric driving without the dependency on external power sources.

While charging infrastructure is improving, widespread availability will take time. Long charging times for emergency vehicles can be impractical; EREVs are ideal for such uses, primarily operating on battery power while engaging the combustion engine only when necessary, without affecting overall performance.

Regarding costs, EREVs are generally cheaper than equivalent PHEVs due to their smaller batteries. This smaller battery size not only reduces the vehicle cost but also increases availability amid limited lithium supplies and the emerging sodium-ion battery market.

Despite their advantages, EREVs have their drawbacks. For instance, when the combustion engine is inactive, it adds extra weight, and many onboard generators are used less than 10% over the vehicle's lifespan—often meaning around 300 kg of unutilized components. Furthermore, while electric cars typically incur lower maintenance costs, EREVs necessitate regular checks on their complex engines, similar to traditional vehicles, which may lead to reliability concerns.

Building a compact city-oriented electric vehicle is straightforward, while developing a small EREV is significantly more challenging and can be costlier than manufacturing entirely electric vehicles. Such vehicles make economic sense in larger models requiring substantial batteries.

Moreover, the gasoline engine requires space, which could reduce trunk capacity or frunk size. This raises safety implications, affects crash ratings, and diminishes reliability compared to purely electric vehicles.

Choosing the Right Option

If you believe an EREV could resolve your transport challenges, it would be advantageous to reside in China, where these vehicles are highly sought after, and the EREV market is rapidly expanding. Unfortunately, global options are currently limited; we await the arrival of the Mazda MX-30 R-E, featuring a unique rotary engine, which could present various challenges for consumers.

Another option is the LEVC TX, a versatile London taxi available in both passenger and van configurations. Manufactured by Geely using Volvo parts, it enjoys solid build quality and adequate performance. If you’re comfortable with sharing your cab with strangers, it could be a fascinating vehicle choice, offering significant interior space, accommodating up to eight passengers or two with ample legroom comparable to a Rolls-Royce Phantom.

The AITO M5, one of the early EREVs in the Chinese market, features a 1.5-liter turbocharged 4-cylinder engine with 123 hp—this power does not contribute to the overall performance since it doesn't connect to the wheels. With a battery capacity of 40 kWh, the car offers an electric-only range of 140 km. Once that range is surpassed, the extender activates, providing an overall range exceeding 1,000 km (NEDC). Available in both 2WD and AWD versions, the latter boasts two electric motors delivering a total output of 315 kW and 720 Nm of torque, capable of achieving 0 to 100 km/h in just 4.4 seconds. The claimed 1,000 km range indicates a consumption of 6.5l/100km to cover 860 km.

The Li Auto family exclusively includes EREVs, initiated by the Li ONE and now succeeded by the Li L9. Additionally, the Li L8 and Li L7 come with a 42 kWh battery paired with a 1.5-liter gasoline generator. The company claims a total range of 1,315 km for the L8, with a battery electric range of 210 km.

The larger Li L9 employs a similar range extender, featuring a slightly larger battery of 44.5 kWh but a reduced electric range of 180 km. Interestingly, both models share the same total range of 1,315 km. Details regarding the upcoming Li L7 are forthcoming, though it will likely utilize the same generator and a battery around 40 kWh.

Li L9 includes a 65-liter fuel tank, providing a fuel range of 1,135 km (180 km electric), leading to an average consumption of 5.7l/100km—a commendable figure for a vehicle larger than the Mercedes EQS SUV.

The Voyah Free represents another Chinese EREV available with a battery-only option. This version features the same 1.5-liter turbocharged 4-cylinder engine alongside a 33 kWh battery pack. With two electric motors, it peaks at 500 kW (671 hp) and 1,000 Nm of torque, providing a total range of 860 km (530 miles) with a 0 to 100 km/h time of 4.6 seconds.

Equipped with a 56-liter fuel tank, the exact electric-only range remains unconfirmed, but it is estimated to be around 160 km. Consequently, the range extender facilitates approximately 700 km of travel, translating to a fuel consumption of 8l/100km.

BYD boasts a diverse lineup of EREVs, including popular models like the Song Plus, Tang, and Han, classified under the DM-i trim (Dual Mode). Featuring a 1.5-liter engine that powers either a 10 or 21.5 kWh battery, all three vehicles claim to exceed a combined driving range of over 1,000 km.

The BYD Han DM-i, with the larger battery, can achieve 242 km in electric-only mode, in addition to a further 1,158 km via the range extender. Thus, its 50-liter fuel tank yields an average consumption rate of 4.3l/100km.

Final Thoughts

It is essential to note that EREVs are not a recent innovation. Originally, this concept was employed in early electric vehicles during the 1900s, relying on gasoline generators due to unreliable battery technology. More recently, models like the Chevrolet Volt and BMW i3 REx were effectively EREVs, despite failing to achieve significant sales and ceasing production. The Volt’s design allowed it to drive the wheels directly via a sophisticated clutch, while the i3 REx’s fuel tank served solely as an emergency resource.

Will EREVs capture widespread attention? The future hinges on the speed of charging infrastructure development and advancements in affordable battery technology—two critical areas currently hindering progress. EREVs may serve as a solution in the interim, bridging the gap as global governments pursue ambitious environmental goals. While they do not address the long-term emissions issues, EREVs offer a practical transition from the past to the future.