A plug-in hybrid that cures drinking problem!

You’ll remember from school that you can’t divide a number by zero. It’s why I couldn’t calculate the mileage of the Volvo XC90 T8 because after 147km, the petrol it consumed was 0.0 litres. It came to the office with around half a tank of petrol, and a week later, it went back with the same half tank. Sounds crazy, doesn’t it? But it’s quite possible in a plug-in hybrid, which can be driven a fair distance using just electricity.

Slowly does it

Plug-in hybrids combine a petrol engine with an electric motor, just like a conventional hybrid, but the difference with a plug-in is that it carries a large battery that can be charged from electrical outlets and this is what gives it the extra range.

Now the plan was to use the XC90 T8 plug-in hybrid for a working week without using a drop of fuel. Ground zero was the Autocar office where we’ve just fitted our first fast charging unit, which no doubt will be used by us a lot in the future. A full charge gives the big Volvo a handy range of 40km and making the task of driving only on electricity easier is the fact that I don’t live far from the office. A round trip is only 16km, so with full charge at the office I could do the daily back and forth drive without having to recharge at home.

It takes me just 30 seconds to unplug the T8’s thick umbilical chord-like charging cable before I haul myself up into the high but comfy driver’s seat. But first things first. I toggle the Drive Mode controller to ‘Pure’, which drives the car only with the 87hp electric motor. I ease the big Volvo out of our parking bay with a gentle prod of my right foot. The thing is that even in Pure mode, if you flex your foot hard, the petrol engine kicks in because the hybrid system thinks you want instant power. So, the trick to stay completely in electric mode and keep the engine from waking up is to use minimal accelerator pedal inputs.

Short and sweet

On the first day, it took me around 40 minutes to do the 8km run home; this works out to an average speed of 16kph, which is pretty much the rush hour norm on the choked streets of Mumbai. However, the range dropped to around 17km by the time I got home, with the hybrid peripheral battery cooling and air-conditioning systems chewing up a fair amount of juice. Would I make it back to work the next morning without running out of charge?

I left early, traffic was smooth and flowing, and it took me just 25 minutes to reach the charging dock at the office, with enough charge left for around 5km. Cutting it fine? If it were a pure electric car, you would be in a state of total panic, but with a hybrid, you always have a tank of fuel to fall back on and that’s why a plug-in hybrid makes such sense.

For the next five days, I used the T8 not just for the office to home run, but also for short runs to the club, dinner engagements, press conferences and the like, charging the car every time I got back to the office. It never ran out of juice and I never had to fall back on the engine to get me home. In fact, I never even heard what the engine sounded like.

Yes, it’s a different story on the highway where you quickly run out of charge, and the hybrid advantage is negated by the T8’s small fuel tank and the engine’s thirst for fuel.

It’s only on short runs that plug-in hybrids really shine and make a lot of sense. More than anything, my zero emissions week with a massive SUV left me with a nice, guilt-free feeling that lingers on.

Hormazd Sorabjee is one of the most senior and much loved auto journalists in India, and is editor of Autocar India

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From HT Brunch, May 5, 2019

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