Bold new (Amp)era: ZF shaping new generation of range extenders

ZF’s eRE and eRE+ REx products, depicted above, are due to arrive in 2026.
ZF’s Scharrer sees a future for REx, but regulators need to see the benefits too

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Opinion

4 mins read

22 July 2025

Let’s wind back to 2012: Britain is gripped by Olympic fever as Vauxhall launches the Ampera and the UK’s first ‘plug-in’ hybrid decisively beats the Volkswagen Up to European Car of the Year glory in the process.

Within 12 months the Ampera will have a carbonfibre-cored rival in the unlikely shape of the BMW i3, another car using its petrol engine purely as a range-extender in what appears to be a movement gathering momentum.

Yet more than a decade later both cars feel like distant memories and range-extender (REx) technology – essentially where an engine charges a drive battery instead of powering the car itself – remains remarkably niche.

Mazda will sell you its MX-30 crossover with a dinky rotary generator on board, while LEVC London cabs deploy REx tech on a larger scale. But most customers opt for a battery-electric vehicle (BEV) or parallel hybrid and ignore a once-pioneering stepping stone between the two camps.

ZF reckons that is about to change. The German automotive and industrial tech giant has its hand in all manner of components and its 8HP eight-speed automatic transmission is a mainstay of the industry, with dozens of applications since its late-noughties introduction.

ZF’s latest range-extender systems, eRE and eRE+, are designed to speed up car makers’ evolution of hybrid and EV technology – and help them mould around increasingly tumultuous market conditions.

“It could potentially revitalise the somewhat sluggish electric vehicle market in Europe and the US,” says the company. “Major manufacturers like Hyundai, Ford and Stellantis are showing interest in range-extender technology and planning to launch vehicles equipped with it within the next two years.” Its halo gearbox certainly has a good track record of breaking down rivalries and supplying multiple, competing manufacturers all at once.

So what’s new compared with a decade ago? “When you look at the history of range-extenders, [engines] like those in the i3 were designed to help you in utmost urgency,” says ZF’s e-mobility R&D boss Otmar Scharrer. "This has changed. Range-extenders are now much stronger and more powerful.”

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Cooling, packaging and refinement have improved as REx cars move away from shrunken engines to proven larger units with a strong, efficient mid-range and capable of running frequently rather than being dipped into sparingly. A naturally aspirated petrol four-pot is optimal.

While neither of ZF’s new offerings drives the wheels directly – it’s key to their MO – they can work with up to 200bhp of engine output and either plug and play with a manufacturer’s existing engine and motor or use a clutch and differential to create a more flexible set-up where an intermediary generator can drive the wheels. Both options can hook up to 400V or 800V charging architecture.

Scharrer sees huge market potential in areas where charging infrastructure remains a barrier to EV sales success. “I hear comments that this is a very short-term technology and that regulations aren’t following,” he laments. “But if you have a car capable of going 155 miles fully electric, then it has a range-extender for the countryside, why should you be banned from driving it in the city?

“We involve ourselves as much as we can in regulatory discussions. In China, to keep the status of a ‘new-energy vehicle’ [EVs and plug-in hybrids], you must not connect the internal combustion engine to the wheels.

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The EU has not finally decided what to do with range-extenders, but I think they realise that this is an interesting opportunity to offer a product which is less dependent on rare materials and cell chemistry because you need a significantly smaller battery.

“They want to understand what the pros and cons are. The whole mobility community is ready for these discussions, because we need them. The past regulation of BEVs has shown that we cannot push things into the market against the customers’ will.

The easier a solution is, the higher its chance of surviving a long time. And this is quite an easy solution. I personally expect that we will see it beyond the next five to 10 years. I think there will be plenty of applications which really excite people.”

Confident words when sales of new hybrids are due to cease in Europe after 2035. Indeed, Ineos, Lotus and Volkswagen are three more names reportedly dabbling with REx powertrains as we speak. Maybe the Ampera was right all along.