PLUG-IN hybrid electric vehicle (PHEV) variants once came with major price and packaging penalties, however the $118,900 (plus on-road costs) X5 xDrive40e is at least identically priced and equipped to the existing diesel-engined X5 xDrive40d. No prizes for guessing what the ‘e’ and ‘d’ stand for, though.

There are, however, also comparisons to be made with the $86,200 X5 sDrive25d and its $91,200 all-wheel-drive equivalent, and the $102,900 X5 xDrive30d that sit below the duo of ‘40’ models in BMW’s best-selling model range.

Practically speaking, going petrol-electric reduces boot volume by 30 per cent compared with all other X5s, to 500 litres, or 5L larger than a 3 Series Touring. It also means forgoing a spare tyre and the option of seven-seat capability, because 96 lithium-ion batteries now reside under the rear floor.

More compromise comes in terms of a kerb weight that totals 2230kg, or 120kg more than an X5 xDrive40d. The batteries contribute 105kg alone, but BMW has made two-mode adaptive dampers with rear air suspension standard on the plug-in X5 to compensate, where it is a $3200 option on all diesel versions.

With the statistical differences of going electric clear on the board first, the X5 xDrive40e can then attempt to woo on the road with its silent driveability and remarkable claimed efficiency.

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