THE second-generation Q7 hasn’t even reached its first birthday yet there’s a new version just around the corner.

Lighter, stiffer and packed with more technology than ever before, the new Q7 is exactly the kind of car that big Audi buyers are looking for. But this e-tron version is something altogether different.

Mixing diesel power with electric motors, the Q7 e-tron is a plug-in hybrid promising exceptional fuel consumption and emissions alongside similar performance, pricing and barely diminished practicality.

To look at there’s nothing to distinguish the electric Q7 from its combustion-only counterpart.

The Q7 e-tron is unquestionably a sizeable car but in e-tron guise there are a couple of compromises. The substantial battery pack sits in the boot where the third row of seats would normally sit, so the Q7 e-tron is a five-seater only. The boot space is also reduced.

The cabin itself is as spacious and comfortable as the standard Q7, with generous space front and rear as well as excellent materials. The Q7’s virtual cockpit gives you a full update on what the complex powetrain is up to.

Defaulting to electric mode on start-up, acceleration from rest is smooth, near-silent and brisk considering its size.

There are four operation modes to choose from: EV; hybrid; battery save, where the charge stays unused until you request it; and battery charge, where the engine will charge the battery while you drive.

But the Q7 has another trick up its sleeve. You can leave it in hybrid and it will engage the battery, the diesel engine or both depending on how you drive, but if you use the sat nav Predictive Assistant will determine what combination to use based on the road – and even the traffic – ahead.

On the one hand the Q7 in e-tron form is significantly more expensive than a comparable diesel model, but that extra outlay brings with it a number of significant advantages.

As well as being obviously cleaner and greener than a standard diesel, it qualifies for the government’s £5,000 grant, and will pay no vehicle excise duty or London congestion charge.

Not everyone needs so much space and comfort, so there are smaller plug-in hybrids and conventional electric cars that can be as frugal, but no rival can offer the same combination of comfort, space, luxury and economy at the same time.

FACTS AT A GLANCE

Audi Q7 e-tron, £65,000 (est)

Engine: 3.0-litre diesel unit plus electric motor producing 369bhp and 516lb/ft of torque

Transmission: Eight-speed automatic driving all four wheels

Performance: Top speed 140mph, 0-62mph in 6.0 seconds

Economy: 166.2mpg combined

Emissions: 46g/km of CO2