First Drive: BMW X5 xDrive40e M Sport 5dr Auto

What's this?

A plug-in hybrid BMW X5. It's actually the first plug-in hybrid from the BMW mothership, period. Previous cable-charged BMWs have hatched from the ‘i' sub-brand, which, in the quirky i3 city car and exotic i8 flagship, has produced two of the finest cars of any sort on sale today. Bodes well...

Give me specs...

The X5's petrol engine is the same 2.0-litre four-cylinder turbo job you'll find in any BMW badged ‘28i' That means it's the most powerful four-pot petrol the company makes: good for 242bhp and 258lb ft.

Allied to that is a re-honed version of the i8's electric drive motor. In X5-punting trim, it adds 116bhp and 184lb ft of instant-access torquiness. The flipside is another 150kg of batteries, and the loss of under-floor boot storage as a result.

BMW says its customers won't notice, as internal research shows buyers don't tend to bother using the shallow hidden cargo bay anyway. Rear seat space is unaffected, so it's a clever installation overall.

Is it fast?

Not really. The claims are healthy: 62mph is apparently dispatched in a prompt 6.8 seconds and it'll run on to a limited top speed of 130mph. Total output is 309bhp - identical to the X5 40d, with its 3.0-litre straight-six turbodiesel power. Both cost around £56,000 too.

So I'm no longer paying extra for adopting hybrid tech?

That's the idea. But, don't go expecting diesel levels of urge. The 40e is down 132lb ft on its oil-burning twin, and you can feel that shortfall (and the weight gain) when you ask for maximum go.

Don't worry, your new X5 won't be out-dragged by a golf cart down your local club, but it's a tad strained for those opportunistic open-road overtakes that delight buyers of posh SUVs...

What's it like at a more relaxed pace?

Much better. If you're going to build a hybrid, it's crucial you nail the calibration between the power sources chiming in, and BMW's is up there with the best. The 40e glides away from standstill on electric power, and will whoosh along at up to 75mph, with a maximum range of 19 miles, in MAX eDrive mode.

When the petrol engine is required, you'll only notice it from the rev counter flicking up from zero. There's no vibration to speak of, and very little extra noise. A Cayenne e-hybrid can't quite pull off the same party trick.

BMW's also thrown in a ‘Save Charge' setting, which avoids draining the battery if you're anticipating some urban driving later in your journey. Most drivers will leave the car in Auto eDrive mode, and let the clever algebra decide when the e-motor should get stuck in.

And how much fuel will that use?

Interestingly, BMW's official bumf tacitly admits the claims of 85.6mpg and 77g/km (which misses out on the UK government's £5000 plug-in grant) are a result of the flawed NEDC economy test. Instead, BMW calculates that with a full battery charge (which takes around two hours) you should score about 43.5mpg on a what Munich deems ‘an average commute'.

Is that realistic?

In the evidence of our ‘average' test drive, it's still a tad optimistic - we got 36.8mpg. For a heavy, bluff, two-tonne SUV, it's still pretty good, certainly on a par with what the lustier diesel would manage.

But to really crack impressive economy numbers, you're going to have to pay more attention to your driving style, and what mode the car's in.

What's it like as, y'know, a car?

A pretty normal X5. There are no ‘look how green I am' touches in the cabin, just a subtle eDrive badge. Even the dials are standard. You can even buy an M Sport pack, for the ultimate paradox in looking racy but saving pennies on petrol.

The steering's oddly sticky just off centre, though. It's only a footnote here because a hybrid X5 is hardly aiming for the usual heights of BMW's ‘Ultimate Driving Machines', is it?

Is the diesel still the X5 to have?

If you're still hugely averse to the black pump and do lots of town driving, the X5 40e makes some sense. But right now, its vital stats aren't quite compelling enough to have us rushing to install the home charging station.