Volvo XC90 T8 versus BMW X5 xDrive40e - twin test

So what other refinements have Volvo and BMW brought to the plugin hybrid SUV to tempt you out of a conventional diesel? We’ve already touched on engines, but here’s the detail. Both are petrol motors displacing just under 2.0 litres of volume. The BMW’s is turbocharged to the tune of 242bhp, the Volvo’s both turbocharged and supercharged to produce no less than 313bhp. Not exactly economy-minded four-pots, then – but, in heavy cars often with big batteries to charge as well as motive power to provide, neither could they have afforded to be. Can either turbo petrol really produce better economy than a typical 200bhp four-cylinder diesel?

Both SUVs have around 9.0kWh of lithium ion high-voltage drive battery on board, the Volvo’s packaged in such a way as to preserve its seven-seater status and the five-seat BMW’s not-socleverly packaged. While the BMW deploys its battery’s electrical energy through one electric drive motor producing up to 111bhp and 184lb ft, the Volvo can use both its main electric drive motor and its lesser starter-generator motor to drive the wheels, making for up to 133bhp and 280lb ft of electric power – in theory. Thirty-love to Volvo.

In practice, the XC90’s powertrain doesn’t ever commit absolutely every last horsepower to the wheels. Even so, the Volvo’s total claimed ‘system output’ maximums are comfortably greater than the BMW’s, where Gothenburg’s 401bhp and 472lb ft makes Munich’s 309bhp and 332lb ft look rather limp. Moreover, partly for technical reasons and partly because of the way that these cars’ particular powertrains blend electrical and combustive power, it’s the Volvo’s zero-emissions system that feels much the more accessible and powerful on the road.

However, before we get into all that, to the hard-nosed business case for ownership of these cars. For the private buyer, it’s convincing enough: these aren’t prohibitively expensive vehicles, they perform either as well or better than their diesel equivalents, they should hold their value decently well and, provided you do plenty of shortrange motoring and you’re prepared to do plenty of charging, they’ll be relatively cheap to run.

For the fleet driver, the case is truly persuasive thanks to the effect of that competitive pricing and an outstandingly low benefit-in-kind tax liability. Rated at 78g/km of CO2, the X5 40e qualifies for company car tax at just 15% of list price – half the liability of a like-for-like 40d diesel. The XC90 T8 is better still, emitting just 49g/km of CO2 and qualifying for BIK tax at just 7%.

And so, taking account of a typical monthly contract hire payment and company car tax outgoing combined, a 40% taxpayer could save around £300 a month with either of these cars compared with their like-for-like diesel rangemates. A staggering £750 per month, even, compared to our luxury SUV class favourite, the Range Rover Sport SDV6. And, in spite of its higher list price and contract hire rate, the Volvo finishes up within £25 a month of the BMW for a business user, thanks to that 49g/km CO2 rating. Incredibly, that’s the same as a BMW i8.

On to the matter at hand, then. You always have to go out of your way to set a fair and revealing test for something as broadly talented as a modern luxury SUV; for those with ultra-sophisticated petrol-electric powertrains, farther still. So, for the XC90 T8 and X5 40e in particular, we concocted a 190-mile test route split into two parts. The first part would be a 40-mile mixed commuter run taking in urban roads, trunk roads and motorway, departing with a full battery charge and finishing at Hopwood Park services south of Birmingham. This was designed to give us a reliable and comparable indication of what performance, driveability and economy a UK owner might experience on his daily grind.

The second part of the route would involve forging 150 miles west along plenty more motorway, as well as the challenging A and B-roads of the increasingly mountainous north Wales. We’d make time for photos and finish up at the most apt place we could think of for a pair of mains-assisted SUVs: the Dinorwig hydroelectric power station, Snowdonia – known to patrons of the nearby visitor centre as Electric Mountain.

However, we mustn’t move on to functional and dynamic considerations without first acknowledging a decisive fact in this competition: the sizable difference apparent between these cars on perceived quality, desirability and cabin allure. The XC90 is, quite plainly, the more appealing product. Whether you happen to prefer the straight-edged, tough-yet-smart geometric rigour of Volvo’s new design language to BMW’s freerflowing but fussier look is up to you. Either way, you couldn’t fail to be more impressed by the tactile substance and contemporary style of the XC90’s interior, which makes the X5’s look and feel unimaginative and ordinary by comparison. It’s not that the BMW’s switchgear looks or feels cheap; more that the Volvo handbrake switch, for example, clicks with the tactile allure of the power button on an audiophile’s £10,000 hi-fi amplifier.

The cars are evenly matched on practical fronts such as cabin space: where the Volvo scores (on boot space and seven-seat passenger carrying), it scores just about hard enough to deserve a relative recommendation, while the BMW hits back with more comfortable seats and a useful split tailgate.

Mr and Mrs Sensible will, of course, also be keen to find out which is the more frugal car here in real-world commuter running. Enlightenment time, then. Over an initial mixed 40-mile trip in rushhour traffic, used similarly to how most UK owners are likely to use it on a daily basis, the XC90 returned an indicated 44.6mpg to the X5’s mere 34.9mpg. So one of these cars is a potential diesel-beater, under the right circumstances – while the other may not be.

And, with a full charge in the battery to deploy, part one of our test drive route also revealed that the XC90 not only goes marginally farther before its cells are depleted but also feels much the more responsive, powerful and assured car of the two when running on electric power. In the X5, the electric motor drives through the same transmission as the combustion engine, which often means you have to tolerate the same momentary lowspeed delays and interruptions in power delivery as you would when the combustion engine is running, as the gearbox engages, disengages and shuffles ratios. But the XC90’s entirely electric, directly driven rear axle gives it much cleaner throttle response at low speeds and something much more akin to the instant, effortless waft of a true EV.

As your speed builds on trunk roads and dual carriageways, the BMW’s electric motor begins to feel weaker than that of the Volvo, struggling to pull higher ratios without the assistance of the petrol engine. But in the XC90, up to about 60mph, it always seems like there’s enough electric oomph under your right foot to keep the piston engine from intervening – while there’s charge in the battery, at least.

Onto part two of our route, then, and more inviting and open Welsh A-roads. With batteries now mostly depleted, the fuel efficiency of the cars depends mostly on how drivable they are, and how effective their hybrid systems are at scavenging energy. Pretty soon, both trip computers are indicating considerably less impressive economy numbers: low 30s from the Volvo, and high 20s from the BMW. But we’re driving the cars quite hard, and asking them to cover greater distance than may be routinely required of them. High-mileage drivers take note: you’re probably still better off in a conventional diesel than either of these cars.

A fulfilling motoring life isn’t all about miles to the gallon, though. Twisting mountain roads will quickly remind you of that, if you let them. While both of our SUVs take to them with greater vigour and involvement than a typical diesel 4x4, it’s the Volvo that shines more brightly on them – completing something of a rout for its maker.

While neither of our cars has the telling muscle of a proper performance 4x4, the XC90 has something almost as good: a real wallop of tractive urge on tap between about 40 and 70mph, right where you need it. Both cars have sporty modes for their suspension, powertrain and steering systems, and both cars allow you to manually select your own gears. However, the Volvo takes off more quickly than the BMW when everything is set just-so – quick enough to shade almost any diesel SUV I can think of – while the X5 can feel a little inconsistent and strained when overtaking.

The Volvo’s ride and handling shade the BMW’s by an even wider margin. It corners with greater poise and natural balance than the BMW and rides much more fluently. All this is helped by it having the more weighty, feelsome and incisive steering. The Volvo is the more softly sprung car, so it rolls a touch harder and feels slightly underdamped occasionally, but it has distinguishing ride comfort.

The BMW handles gamely when harried, just as you’d expect it to, but its steering is too slow around dead-centre, too muted on feedback and just a bit too imprecise and inconsistent at times to inspire the confidence you need to tackle a twisting road with much gusto in a really big car. The X5’s ride seems needlessly firm: hyperactive over camber changes and through ruts, and slightly coarse with it – at a guess, at least partly as a result of the runflat tyres our test car came fitted with. All in all, it feels like a car struggling against its dynamic limitations next to one that’s much more at one with them.

It leaves us with a singular conclusion. Before this test, I wasn’t sure that the financial case for a petrol-electric luxury SUV could stack up against a diesel – but it can. I didn’t expect the XC90 T8 to be capable of driver appeal on the one hand and rational appeal on the other: to deliver on performance, handling, refinement and creditable economy.

But it is, and does. If the future of the luxury SUV comes with a plug, we can trust Volvo to usher it in. Your move, Audi.

Volvo XC90 T8 AWD R-Design

Price £63,555; 0-62mph 5.6sec; Top speed 143mph (limited); Economy 134.5mpg (combined); CO2 emissions 49g/km; Kerb weight 2296kg; Engine layout 4 cyls, 1969cc, turbo and supercharged, petrol, plus two electric motors; Installation Front, transverse, frontwheel drive (IC); rear, transverse, rear-wheel drive (AC); Power 401bhp at 5700rpm; Torque 472Ib ft at 2200-4500rpm; Power to weight 175bhp per tonne; Specific output 160bhp per litre; Compression ratio 10.3:1; Gearbox 8-spd automatic; Length 4950mm; Width 2008mm; Height 1776mm; Wheelbase 2984mm; Fuel tank 50 litres; Range 24 miles (AC), 360 miles (IC, approx); Front suspension Double wishbones, air springs, adaptive dampers, anti-roll bars; Rear suspension Multi-link, air springs, adaptive dampers, anti-roll bars; Brakes 345mm ventilated discs (f), 320mm ventilated discs (r); Wheels 9.5Jx22in; Tyres 275/35 R22, Pirelli Scorpion Verde

BMW X5 xDrive40e M Sport

Price £56,705; 0-62mph 6.8sec; Top speed 130mph (limited); Economy 83.1mpg (combined); CO2 emissions 78g/km; Kerb weight 2305kg; Engine layout 4 cyls, 1997cc, turbocharged, petrol, plus electric motor; Installation Front, longitudinal, four-wheel drive (IC and AC); Power 309bhp at 5000- 6500rpm; Torque 332Ib ft at 1250-4800rpm; Power to weight 134bhp per tonne; Specific output 121bhp per litre; Compression ratio 10.0:1; Gearbox 8-spd automatic; Length 4886mm; Width 1938mm; Height 1762mm; Wheelbase 2933mm; Fuel tank 85 litres; Range 19 miles (AC), 560 miles (IC, approx); Boot 500-1720 litres; Front suspension Double wishbones, coil springs, adaptive dampers, anti-roll bars; Rear suspension Multi-link, air springs, adaptive dampers, anti-roll bars; Brakes Ventilated discs (f), Ventilated discs (r); Wheels 9.5Jx20in (f), 11.5Jx20in (r); Tyres 275/40 R20 (f), 315/35 R20 (r), Dunlop SP Sport Maxx GT runflats