Matt Joy says Volkswagen in mixing it up with a new hybrid version of its Touareg combined petrol power and electric motors.

Hybrid loosely translates as sacrifcing everything in the name of fuel economy and emissions – or so common opinion would have you believe. But that's not necessarily so – combine a petrol engine and an electric motor with performance in mind and you can use the inherent advantages in both systems to good effect.

Unlike some of its rivals, this is the exact approach that Volkswagen has taken with its Touareg Hybrid. The second-generation Touareg we are already familiar with, it having cruised elegantly into showrooms more than a year ago with an all-diesel line-up. And it's hard to make a case for having a petrol engine given the strength of the diesel range. The 3.0-litre TDI can return 38mpg combined while the megalomaniac in you will want the 4.2-litre V8 diesel that can crack 62mph from rest in under six seconds. Performance cars won't see which way it went.

But anyone who still isn't keen on the slippery black stuff – and diesel's never a nice thing to handle – doesn't have a great deal of choice when you get something this size. But help is at hand, because the Touareg is related to another sport utility vehicle that also has some good genes – namely Porsche's Cayenne. You can specify that car with an assortment of bonkers petrol options, but arguably the most relevant is the petrol hybrid.

That same system appears in the Touareg Hybrid, and it mates a 3.0-litre petrol V6 to a pair of electric motors driving the rear wheels. That means you still have four-wheel drive and you put petrol in the tank instead of diesel, but when the conditions are right you can emit nothing but the faint whirr of an electric motor doing its stuff.

Like any proper hybrid the Touareg doesn't need any extra brain-power on your part. Get in, start up, slot the transmission into drive and away you go. If there is charge in the battery already and you gently squeeze the accelerator, the Touareg Hybrid will sail silently away from rest up to a claimed top speed of 31mph, all on electric power. Such is the silence and smooth operation that you are encouraged to do so, never mind the eco kudos that comes with it. Go above 31mph or press the accelerator hard and the petrol engine kicks in.

Like any conventional hybrid the batteries charge when you press the brake pedal and activate the regenerative braking. This needs a delicate touch at first and a little acclimatisation, but patience is rewarded by the battery graphic slowly filling up, ready for the next bit of lower speed driving.

You won't want to drive it like this all the time however, for although the Touareg is as refined, luxurious, comfortable and capable as you might expect, what comes as a complete surprise is its supercar alter-ego. Push the accelerator to the floor, both petrol engine and electric motors combine and you are blasted down the road with vigour that will shock you and certainly put other road-users on the back foot. It looks exactly like any other Touareg from the outside but the performance on offer suggests it should actually be the Touareg GTI.

More important however is where the Touareg Hybrid stands in the grand scheme of things. As the Porsche connection might suggest, this hybrid is more about cleaner performance than the ultimate in economy – it can't beat the 38.2mpg combined figure of the 3.0-litre diesel for example. But it can beat its CO2 emissions however, even if it is only by 3g/km. Yet to really understand its place in the world you need to compare it to the Touareg V8 diesel.

They can both reach nigh-on 150mph and their acceleration times from 0-62mph are just half a second apart at around six seconds. So very quick then, for something that weighs two tonnes and will carry your whole family in comfort. The Hybrid can manage an extra three miles per gallon, for a combined figure of 34.4mpg, over the diesel, and don't forget the price difference at the pumps. An efficient petrol like this also produces fewer particulates than a diesel. The final nail in the coffin is price. Neither are cheap, sitting at the top of the range, but the Hybrid is a useful �1,610 cheaper – enough for more than 1,000 litres of petrol that will get you further than the diesel could manage.