There are advantages to driving a large SUV and for many, it's the ride height, the interior space and the feeling of safety lent by being the biggest thing around that drives appeal.
The downside, of course, is that you're hauling a huge amount of car around the place. These offroaders and softroaders are typically the greatest gas-guzzlers, especially when combined with a powerful engine to give you the satisfactory all-round performance you expect from BMW.
The solution is to modernise the powertrain. BMW now offers a PHEV version - plug-in hybrid electric vehicle - to blend traditional X5 luxury convenience with modern efficiencies. The X5 eDrive was the first plug-in hybrid announced by BMW, with the 2 Series Active Tourer and 3 Series Saloon also joining the green party.
BMW X5 xDrive40e: Familiar design
There are two camps when it comes to hybrid car design. There's statement design, typified by the Toyota Prius which divides opinion, then there's conventional integration into existing cars. While there's been a lot of interest in Toyota's efforts, we've always felt that the tipping point for electric vehicles (be that pure or hybrid) will come through more traditional positioning.
With that in mind, looking over the hulking lines of the X5 40e, there's little to give away that it's carrying batteries, that it might be greener than its regular combustion engine stable mates. The 40e, as the name suggests, is pitched as an alternative to the 40d, here dressed with M Sport trim (SE also available).
Within this subtle approach to hybrid design, there are only a few small indicators on the exterior of the X5 eDrive that reveal its clean secret lurking within.
There's the eDrive moniker on the rear, which you'd probably dismiss as the xDrive badge at a glance, but then there's the charging point on the front right-hand wing. Just as there's a hatch on the rear left-hand wing for old-school fossil fuel, there's one at the front for electricity.
Otherwise, this is every inch a BMW X5 M Sport, riding on 20-inch wheels here and carrying the hallmarks of BMW's latest family design, with creases rippling the bonnet and that bold kidney grill at the front, boosted with M Sport external body work for meaner kerbside looks, with those gaping front intakes and body-coloured sills.
But adding a battery to the X5 isn't without consequences and those looking for a 7 seater will feel the sting, as there's no option for a third row of seats. The space they would occupy now houses the battery in the boot floor. That sees the internal storage space come out at 500 litres, losing about 150 litres over the regular model.
BMW X5 xDrive40e: Behind the wheel, ahead of the curve
Slip into the driving seat and that exterior design story continues within. Although the eDrive system takes lessons learnt from the BMW i models, the X5 keeps things pretty much as you'd expect inside. There's the occasional eDrive marking again, but things are otherwise exactly as you expect them to be.
You don't get the i8's fancy digital display, instead offering regular dials, adapted. The left-hand dial is your conventional speedo, the right-hand dial is the rev counter, with the bottom section dedicated to eDrive. This displays the battery charge status and whether you're charging or discharging the battery.
Elsewhere you'll find an eDrive button to control how the car uses its power. There are essentially three power modes: pure electric (Max eDrive), auto (Auto eDrive) and finally using the petrol engine, which can also charge the battery.
The normal driving mode is Auto eDrive and this balances the two power supplies, basically using electric up to 44mph. This is the mode that will see you pulling away silently before the engine chirps up and joins in the fun as you get going.
For those looking for zero tailpipe emissions, selecting the Max eDrive will let you drive at up to 75mph with a range of about 19 miles. BMW says that the vast majority of journeys made by X5 drivers are under 19 miles, so there's the potential to really lower your consumption of petrol by driving electric only.
That's likely to be the school run, trips to the supermarket, or perhaps your commute to work, and it's here that the greatest efficiencies can be found. For stop-start driving over short distances in congested areas, you're saving a lot of tailpipe emissions.
There's 313hp from the combined electric system and 4-cylinder petrol engine, meaning you can hit 62mph in 6.8 seconds, but with CO2 emissions at about 78g/km in hybrid mode compared to 157g/km for the 40d with the same power output. It's a 2-litre petrol engine, producing 245hp, the rest coming from the electric system.
BMW tells us that the fuel efficiency balance stays in the favour of eDrive on most short and medium journeys. It's only once you're looking at long journeys, such as a lengthy drag on the motorway, that a traditional diesel will be the more efficient. Yes, this still has a large IC engine, so this is really a hybrid for those who don't want to sacrifice the performance and convenience they're used to.
The car will charge the internal batteries, or preserve the charge via recuperation (braking), but when you're parked at home, you can hook it up to the mains. Through a standard 13V socket it will change in under 4 hours, but if you have a BMW i Wallbox (for your i8?), the X5 will charge in under 3 hours. You'll also be able to use public charging points, now appearing in many parking locations, such as shopping centres and supermarkets.
BMW X5 xDrive40e: Uncompromising SUV driving
So far this has been a story about the lack of compromise and that's true once you're underway. Whichever power mode you choose to drive in, this is very much the big SUV experience, responsive enough to keep pace whatever traffic you're sitting in and whatever roads you're on.
The ride is comfortable, perfectly at home on mixed urban roads and able to soak up those slightly larger bumps you might encounter. But the X5 still handles like the large SUV it is and you'll feel it heaving in the corners at speed as you'd expect. As with other BMWs, there are also different driving modes - comfort, sport and eco pro.
As this is an X model, you have all-wheel drive too, giving plenty of traction wherever you choose to take your X5. It's fitted with an 8-speed auto gearbox, which is smooth and fast to respond, giving you power when you need it, such as when exiting a roundabout, without undue lag.
The high ride height gives commanding views with good all-round visibility, which can be further boosted with plenty of technology options. Whether you're picking the regular X5 or the e version, all your options remain the same. Our test vehicle was fitted with BMW's surround view system, as well as the reversing assist camera, removing the angst for those who might worry about slotting the X5 into a smaller parking space.
That's part of a huge range of technology options that will make your drive more comfortable and safer. There's a full range of connected options, from Bluetooth for your phone, through to the car's own internet connection, to deliver services through ConnectedDrive, as well as a special BMW Remote app that will let you check the charge status, or find a charging station. You can also pre-condition the car, changing the heating or cooling remotely.
BMW might not have been the fastest to offer this next-step in driving, but with a cost that's pretty close to that of an equivalent power X5 40d, it's a model you can slip into without feeling you've compromised. It has the luxury experience, all the options and very much the same feel when you're behind the wheel.
You do lose some stowage space in the boot and compared to the 313hp 40d, it's a slower car - nearly a second slower to 62 - with a 120kg increase in weight. But the important thing is that when you put your foot down the X5 xDrive40e responds. This isn't a weak alternative: for many, the benefits will outway the drawbacks.
At the same time, this isn't a huge leap towards cleaner motoring, still packing in a 2-litre engine. This really makes the X5 a car that should appeal to those who might want to race away at the weekend without the worry of a lack of power or range, but otherwise use it mainly for short journeys close to home.
The BMW X5 xDrive40e M Sport will be available from just under £56k. With all the options pictured here, it's a brow-furrowing £62,605, but importantly, it's every inch a BMW. If you just don't want to compromise on your big luxury car, at least you do it with a cleaner, greener, BMW X5.