2008 Paris: BMW 7-Series ActiveHybrid

It won’t be on sale until this time next year, but BMW has responded to Mercedes-Benz’s unveiling of the S400 BlueHybrid by releasing limited details about its own version of the same drivetrain, the 7-Series ActiveHybrid.

Set to make it’s debut at the Paris motor show, the ActiveHybrid will be BMW’s first true hybrid model.

It uses a twin-turbocharged 4.4-litre V8 petrol engine that delivers 407bhp and 442lb ft, working in combination with an AC electric motor that can add another 20bhp and 155lb ft of torque.

No performance claims have been made for the ActiveHybrid yet, but BMW claims it returns 15 per cent better fuel consumption than the new 750i upon which it is largely based, suggesting a combined average of around 28mpg.

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By mounting the hybrid drivetrain’s lithium-ion battery in the same place as the standard 750i’s lead acid unit, BMW has managed to provide the electric 7 with the same interior and boot space as the standard car.

Other systems featured on the new car include further developed versions of the part-time alternator and stop/start systems already offered on other BMW models.

BMW insiders have also confirmed that the same hybrid drivetrain will be developed for the forthcoming ‘baby’ Rolls-Royce saloon.