No half measures: These are the advantages of plug-in hybrids

Aug 20, 2021

Half electric, half combustion engine – plug-in hybrids combine the advantages of both powertrain technologies. You can read about how that works, and which manufacturers include plug-ins in their range, here.

The market for electric is booming – not just for pure e-cars, but also for plug-in hybrid electric (PHEV) cars. In 2020, sales of PHEVs in Germany rose a staggering 342 percent, to 200,469 units sold. That made it the powertrain type with the strongest sales growth in 2020 in Germany. But in other countries, too, PHEVs are proving increasingly popular. Thus in Europe in 2020, a total of 619,129 plug-in hybrids were sold – an increase of 210 percent on the previous year, and around a 5.2 percent share of total sales. In Q1 2021, that figure has even been surpassed once more: With 212,859 units sold, PHEVs have reached a share of around 8.6 percent of all new registrations. That’s strong growth for a type of powertrain which is set to play a key role in decarbonizing the mobility sector. But how exactly do PHEVs work?

How does the plug-in hybrid work?

Hybrids are vehicles with both a combustion engine and an electric motor. However, there can be very significant differences in how exactly the two powertrain technologies work together. On ‘mild hybrids’, for instance, the electric motor is only there to support the combustion engine when accelerating. Conversely, full hybrids are able to run for some kilometers in pure electric mode; the installed battery is recharged via recuperation (energy recovery during braking). Plug-in hybrids go a step further: They have a large battery, with a range of up to 60 kilometers in pure electric mode, which can be recharged externally via a power point. As such, PHEVs are intended to combine the advantages of the two types of powertrain: The energy efficiency of e-cars for short journeys, and the capability of combustion engines to handle long journeys.

The best of both worlds: Experience sustainable mobility and efficient driving dynamics with the BMW 3 Series Plug-In Hybrid. © BMW

What are the advantages and disadvantages of the technology?

One car, two engines: With plug-in hybrids, drivers can choose the appropriate powertrain at all times – whether commuting to work, shopping in town or heading off on vacation. That allows the driver to run the car as economically and adaptably as possible. When they are driving in pure electric mode, they don’t emit any local emissions. In addition, using the e-motor and the right driving style can save between 30 and 80 percent on fuel consumption. And thanks to recuperation, they are also able to convert braking energy into electrical energy and store it in their battery. However, all these advantages are only realized if the PHEV driver also regularly employs the electric powertrain or hybrid mode and charges the battery via the cable. If a plug-in is only driven in combustion mode, the hybrid concept tends to bring disadvantages: Two engines increase the weight, and thus fuel consumption.

What does a plug-in hybrid cost?

The costs of buying plug-in hybrids are generally somewhat higher than those for their sister cars in the combustion engine segment. The reason for that is the need to install an e-motor and a large battery in addition to the combustion engine, which impacts the price accordingly. But there’s plenty of potential for savings with plug-in hybrids. That’s because, if you regularly top the battery up with electricity and drive in electric mode a lot of the time, there’s a saving at the pump. Per kilometer, you are generally paying more at the pump than at the charging point – albeit the difference here is dependent on the current prices of fuel and electricity, and on the respective consumption of the vehicles. A further advantage on costs is the lower wear on e-motors, since they have significantly fewer parts than petrol or diesel engines. Over the long term, that has a positive effect on maintenance costs

Taking all the cost advantages and disadvantages together, some PHEV models even come out better on price than their combustion-powered sisters. For instance, ADAC tests show the Mercedes B-Class as a plug-in achieving an overall average cost of EUR 0.59/km. The diesel and petrol options average around EUR 0.70/km. If the plug-in is a company car, there are also additional cost advantages on tax.

Stopover at the charging station: The Mercedes A-Class as a compact limousine. © Mercedes

What do the EU-wide differences on subsidies look like?

In Germany, a further major cost advantage with PHEVs currently is the environmental bonus (“Umweltbonus”) paid on them; the Federal government has recently raised this again, and extended it to 2025. Under it, plug-ins costing no more than EUR 40,000 currently attract a grant of EUR 6,750, with EUR 4,500 coming from the state and EUR 2,250 from the manufacturer. For PHEVs costing between EUR 40,000 and EUR 65,000, the level of the grant is EUR 5,625 (EUR 3,750 from the state, EUR 1,875 from the manufacturer). Grant programs for plug-in hybrids exist not just in Germany, but in many other European countries too. Behind Germany, where the grant is up to EUR 6,750, grants in Italy and Ireland are comparable, at EUR 6,000 and EUR 5,000 respectively. In other EU countries, however, the amounts are considerably lower; in Sweden, the grant is just EUR 965. And in fact, some EU countries – such as Denmark and Belgium – don’t offer any grants for purchases. Overall, plug-in hybrids currently attract grants in 12 out of 28 EU states.

"Zero emission" in the city, efficiency on the long haul: the Volkswagen Passat GTE Variant. © Volkswagen

Which manufacturers have plug-in hybrids in their range?

Nowadays, practically all manufacturers offer plug-in hybrids. In Europe, particularly popular models in 2020 included the Mercedes A-Class, Volkswagen Passat, BMW 3 series, Mitsubishi Outlander and Volvo XC40. In addition to a wide choice of different manufacturers, there is also plenty of choice on PHEVs when it comes to models too: Whether SUV, compact or sedan – right down to the mini-car, everything is available now. Unlike pure e-cars, this means there’s a far wider choice for hybrids too.

(Stagephoto: © Mercedes; Stagephoto: © Volvo)

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