At the heart of the GLE 350de's driveline is a longitudinally mounted turbocharged 2.0-litre four-cylinder diesel engine that develops 192bhp and 295lb ft of torque. This is supported by 134bhp and 324lb ft from an electric motor mounted within the standard nine-speed automatic gearbox.
Together, the two power sources provide a total system output of 315bhp and 516lb ft – 11bhp shy but equal in torque to the turbocharged 3.0-litre in-line six-cylinder diesel engine of the GLE 400d. For comparison, the turbocharged 3.0-litre in-line six-cylinder petrol engine and electric motor of the X5 xDrive45e deliver a combined 389bhp and 442lb ft.
The combined reserves are sufficient, says Mercedes, to propel the four-wheel-drive GLE 350de from 0-62mph in 6.8sec and up to a limited top speed of 131mph. In electric mode, top speed is limited to 100mph.
The 31.2kWh battery provides the GLE 350de an official electric-only range of between 55.9 and 61.5miles on the WLTP cycle. This correlates to combined fuel consumption of 256.8mpg and CO2 emissions of 29g/km.
The GLE 350de supports both AC and DC charging. With a maximum DC charge rate of 60kW, it can recharge in approximately half an hour.
The large battery has compromised the GLE's boot slightly, however: overall luggage capacity drops from 2055 litres to 1915 litres.
The GLE 350de is among 20 plug-in hybrid models that Mercedes plans to launch by the end of 2020.
New Mercedes GLC 300e is more efficient, thanks to bigger battery
In a further boost to the line-up, Mercedes has also revealed pricing for the updated GLC 300e 4Matic petrol-electric plug-in hybrid.
The BMW X3 xDrive30e rival is available now, priced from £49,687 and equipped as standard with 19in alloy wheels, AMG styling elements and sports seats. Mid-range AMG Premium trim costs £53,187 and brings 20in rims, multibeam LED headlights and leather seats, while top-rung Premium Plus trim includes a panoramic sunroof, a Burmester sound system and the Memory Package from £56,937.
The facelifted GLC variant receives a heavily upgraded driveline that yields a WLTP-certified electric-only range of 26.7 miles and a CO2 rating of 51g/km.
Key among its developments is a new 13.5kWh battery, as used by the C300e and E300e, which replaces a 8.7kWh battery.