CO2 / 15,000 miles compared

[BeerHunter]

I was trying to work out the pollution of various cars earlier and came up with this:

It just seems too incredible to be true!
Have I gone wrong somewhere?

Kev.

 

[user 258]

Hi,

I think so. The next down from the PHEV is about twice the CO2 of the PHEV which should give it a 2 x PHEV reading.

To be fair, you should also factor in the CO2 of the electricity used in order to achieve 148MPG, which also varies depending what generates the electricity.

And to be really fair, you should also factor in the emmisions required to manufacture the battery of the PHEV.

Trying to do a fair comparison is almost impossible.

Kind regards,
Mark

 

[maby]

I was trying to work out the pollution of various cars earlier and came up with this:

It just seems too incredible to be true!
Have I gone wrong somewhere?

Kev.

I think you must have done, but I don't have time to see where. Your CO2 grams per KM column shows the PHEV being about six times better than the large 4x4 but your final column shows it as 152 times better - that really does not add up.

You are also assuming, of course, that no CO2 is emitted in the generation of the electricity that you consume in the PHEV, and the 148mpg is a headline figure that few people will achieve. On the other hand, I would be quite pleased to get 28mpg out of my "large 4x4" - I have to drive quite gently to get 20mpg. Even so, and assuming that you can get the 148mpg out of the PHEV, you are only seeing an environmental performance that is seven or eight times better.

 

[maby]

OK - looked at it again - why are you calculating CO2 (g) per litre? And why does it differ between vehicles? With the partial exception of the Outlander PHEV, the CO2 they emit all comes from burning petrol (or diesel) and the amount of CO2 generated per litre of fuel burned will be pretty much the same - the combustion efficiency is more or less dictated by legislation. The Outlander will also turn in more or less the same CO2 per litre - it is just a standard petrol engine, after all. The difference comes from its ability to run in pure electric mode for some distance which is what brings the headline fuel economy up. It's hybrid systems are not as sophisticated as those of the Prius and its fuel economy is very dependent on the pattern of usage - someone that only ever travels within the limits of the battery range will burn no petrol and could try to claim infinite mpg - though that would be misleading because they are burning electricity instead. If they had a large enough PV installation and really never drew charge from the grid, then they really could claim infinite mpg but those of us charging from the mains grid will get an mpge approaching 200mpg (better if you charge on Economy 7). Once you go beyond the battery range, it becomes a moderately large conventional car turning in something around 40mpg.

 

[BeerHunter]

..To be fair, you should also factor in the CO2 of the electricity used in order to achieve 148MPG, which also varies depending what generates the electricity.

And to be really fair, you should also factor in the emmisions required to manufacture the battery of the PHEV.

To be fair on hydrocarbons, I would need to include the energy involved in exploration, drilling, upstream production, refining, downstream distribution, all the lubrication / metal involved and the fart quotient of each customer, etc, etc, etc.....
As you say, a direct comparison is almost impossible.

Kev.

 

[Highspen]

Then again, if you factor in that your electricity supplier is Ecotricity who claim to buy in all their electricity from wind farms, you will then have to factor back out the carbon cost of manufacturing process of the "windmills" and their transport to site - quite frankly you could drive yourself mad in trying to work it all out.

Hmm....... just had another look at their website and must investigate Ecotricity for my gaff.