Not too long ago, owning a sports-utility vehicle meant you were sworn enemies with Mother Nature. Unwieldy, hefty and thirsty, they were as environmentally friendly as a cow fed on baked beans.

But cars such as the Porsche Cayenne S E-Hybrid and the new Volvo XC90 T8 have shown that SUV drivers can have their cake and not mess up the environment (too much). Following this trend is BMW's first plug-in hybrid SUV, the X5 xDrive40e.

Other than a subtle eDrive badge at the rear and an extra filler cap on the front left side for charging, there is little to give away the fact that this is an X5 with a conscience.

It is the same on the inside too. Besides the missing third row of seats (the space taken up by batteries), there are no other visual signs of its greener credentials.

The car is as beefy as its petrol/diesel siblings. Mated to BMW's most powerful 2-litre four-cylinder engine, as in all 28i models, is a detuned version of the BMW i8's electric motor producing 113bhp. The pair produce a total of 308bhp driving four wheels.

Select the default Auto eDrive mode and the car cleverly decides when to call upon the petrol and electric motor, or both. While this is common among hybrids, the seamless, near silent transition between electric and combustion modes is the best I have experienced, with only a riffle of the tachometer giving the petrol engine's activity away. The Save Battery mode maintains the state of charge in the batteries.

In Max eDrive mode, the car runs on pure electric power for a maximum of 31km and reaches a top speed of 120kmh. It glides along in spooky silence, until you step hard on the gas and call upon the petrol engine.

While the instant torque of the electric motor can be felt, it still lacks the low-down punch of the X5 xDrive30d. Not helping things is the extra 150kg of weight the car lugs around.

Still, its 0-100kmh time of 6.8 seconds is nothing to be sniffed at, especially for a car weighing more than 2.2 tonnes.

Even more impressive is the car's economy figures. BMW claims a hardly believable 3.3 litres/100km. But in the real world, expect to average about 7.5 litres/100km, which is what I achieved. CO2 emission is an iceberg-friendly 77g/km.

What is not so convincing is the X5 xDrive40e's handling. Drive it at half-pace and the car is comfortable and settles into turns nicely, despite its size and heft. But push harder and the steering's numbness and slack off-centre become unBMW-like and distracting. Body roll is also more apparent.

I drove the seven-seater BMW 2-Series Gran Tourer alongside this car and even that felt more fun around bends.

Then again, a hybrid SUV is hardly the machine for spirited driving. With its relative frugality and earth-saving qualities, the X5 xDrive40e is the closest you can get to guilt-free SUV ownership.

•The writer is a contributor to Torque, a motoring monthly published by SPH Magazines.