New Zealand Law Society - Head to head hybrids

Head to head hybrids

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No potential hybrid owner has ever asked me, in my capacity as a little known motoring writer, whether they would be better to buy a Toyota Prius V, or a Porsche Cayenne S e-hybrid. Despite lack of interest in the question, I am going to address it.


a Cayenne-S-E-Hybrid
The Porsche

One factor to consider is how noticeable you like to be. You see to the right a picture of the actual car Porsche sent me.

It was noticeable.

The Prius is less obvious, but still capable of making a driver self-conscious. There's an odd shaped nose, for a start. It looks a bit like the front end of a Womble. Then there's the shape of everything behind the front end.

When Prium were first produced, it was said, by somebody, possibly accurately, that Toyota had concluded, through some sort of market research witchcraft, that hybrids should be an unusual shape, because those who would buy them would want the world to know that they were driving a hybrid and thus saving the planet. Apparently the urge to save the planet, and thus buy a hybrid, significantly decreases if the neighbours are not aware you are doing it.

Of three Prius submodels, the V is the longest, having been stretched to accommodate seven seats. It will appeal to those who value practicality over aesthetics: exhibit B to the far right.


photo of a Prius
The Prius

Appearance aside, a hypothetical disinterested observer might watch you beetle by in your stretched blue Prius and think: "there goes someone who wants us to believe that he/she/non binary individual is saving the planet, but in fact he/she/non binary is merely someone who can't do their sums."

That disinterested observer is not convinced that a headlong plummet toward a Venusian climate will be averted by increasing the total energy cost of building cars by giving them two engines instead of one. The observer even doubts the claimed fuel efficiency of hybrids, once built.

Consider this. The Prius V claims an average petrol consumption of "4.4 litres/100km (combined ADR81/02)". ADR 81/02 is an abbreviation of "Australian Vehicle Standard (Australian Design Rule 81/02 – Fuel Consumption Labelling for Light Vehicles) 2008". ADR81/02 involves simulated urban driving over a theoretical 3.976 km, followed by simulated extra-urban driving over a theoretical 6.956 km. Total simulated theoretical distance: 10.932 km. The alert among you will already be wondering (a) how well that might translate to real world driving, and (b) how the test is applied to a hybrid car, which might be capable of navigating the entire 10.932 km without once troubling the petrol spigot. Even the Cayenne e-hybrid, the second most economical of this brace, will officially cover 22 km on pure battery power.

The answer to (a) is not very. The answer to (b) is that hybrid cars are put through the procedure twice; once with a full battery charge and once with zero charge, and the results averaged. If you think that evens things up, it doesn't. Out in the real world, you are not on battery power for anywhere near half the time.

You might now be asking: if this is true, why do 86% of Auckland taxi drivers buy hybrids? Who knows? Maybe 86% of Auckland taxi drivers are suffering a mass hysteria. Maybe the disinterested observer has it wrong.


Enough of the maths. To the driving. The Prius is not terrible. It's spacious. It stops and starts when asked. It goes around corners in resolutely predictable fashion. I go so far as to say that it is not unpleasant.

The Cayenne, you will be staggered to hear, is more fun. It's big and it's fast and it has lots of buttons and switches.

You can choose to engage battery only, or petrol only, or both at once. You will notice, via various LCD representations, that the internal combustion engine burns petrol to charge the battery, so that the battery can be used to avoid burning petrol (a trick also performed by the Prius). Your inner high school physicist might question the energy efficiency of that cycle. But this is where the Cayenne has a small advantage: it can be plugged into a wall socket, and absorb 22km worth of electricity from a nice friendly hydro dam. It looked too tedious for me to attempt.

Despite the million or so buttons and/or switches, the Cayenne lacks adaptive cruise control: all but de rigueur in expensive automobiles circa 2016. But it does sport remote tyre pressure reading, which is cooler than any kind of cruise control.

Intriguingly, the front of the cabin presents four grab handles: two for the passenger and two for the driver. In any situation where a passenger might feel sufficiently nervous and/or physically unstable to seize a grab handle, the second to last thing said passenger wants to see is only one driver's hand on the steering wheel, while the other clasps a handle. The last thing that passenger wants to see is both driver's grab handles in use; an off road driving technique sometimes known as the Full Thelma and Louise.

William McCartney is an Auckland barrister who practises from Eden Chambers.

Note: Mr McCartney was erroneously referred to as William McCarthy in the print version of LawTalk. Our error has been corrected here.

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