First drive: the Volvo XC90 T8

Wow, Twin Engine eh? Sounds like the sort of notion that Top Gear could really get behind.

Volvo's marketing people thought plain old 'hybrid' sounded drab, so they came up with the 'Twin Engine' badge. And added T8 just for emphasis. The two engines in question being a turbo-and-supercharged 2.0-litre petrol for the front wheels, and an electric one for the rears. In between in a plug-in battery. So, like other XC90s, it's four-wheel-drive, but instead of having a propshaft going down the spine of the car, that space is used by the battery.

If the regular XC90 is already 4WD, what's the point of this?

In Britain, we have to report its main job is to swerve taxes.

Not to save fuel?

OK, here are the numbers. It can do 'up to 27 miles' on electric power. But real-world that's about 18. After that you're operating as a petrol hybrid, but still a big, heavy petrol one. My test run got 25mpg in that mode. Now, if you have an 18-mile total commute, and you diligently plug it in overnight, then you'll do your working week with no fuel at all. But that's only 4,000 miles a year. That means with longer trips taken into account, you'll be doing maybe twice as many fuelled by petrol alone.

Do the math on your total annual petrol bill and it's 33mpg. Which is about the same as a diesel XC90 will give. And the D5 diesel version is £14,000 cheaper.

OK then… ta-da… the tax cost please?

Volvo says these cars will be owned by company-car user-choosers, and they're 40 percent income tax payers. On the 49g/km this car can claim, the company car tax will be trivially small – about £100 a month. And it can get into the London congestion zone for nothing.

But why are you slagging off the T8 when only last week you praised the similar drivetrain of the BMW 225xe?

The Volvo is so big and heavy, so it can't get as far on its electric-only mode. Also it's a lot more expensive to buy than a diesel 4WD XC90, whereas the BMW is priced comparably with the diesel AWD 2 ActiveTourer. And the BMW qualifies for the plug-in car grant whereas most versions of the Volvo don't. That's because the grant is falling to £2500 from 1 March, and available only on cars under £60k. The Government has very sensibly decided that people buying luxury SUVs (or even a Porsche 918) don't need further subsidising by the rest of us taxpayers.

But I'm not exactly slagging off the Volvo, just saying its advantages are not the ones you'd expect.

So what are those unexpected advantages?

It's wonderfully smooth and silent under electric power in towns. When the petrol engine first cuts in from cold, it will sound rough by comparison, even if of course it's a lot more civilised than a diesel. Anyway, once you're running in normal hybrid mode, the switches between engine-on and engine-off and engine-on again are impressively smooth.

Overall performance is pretty solid. The claim is 0-62mph in 5.6s. The petrol engine has the same 320bhp as in the T6 version, and the electric motor adds its own shoulder to the wheel. But at high revs the petrol engine gets annoyingly thrashy. It's best to resist full-throttle excursions and ride the torque, which is generous thanks to the turbo. And the supercharger. And the electric motor. 

Is all the other XC90-ness present and correct?

Yes, the terrific cabin design, the wonderfully comfy and versatile interior, the strong connectivity, the reassuring safety. All boxes properly ticked.