Are Hybrid Vehicles better for the environment than Battery Electric Vehicles ?

This is a claim in the article - https://www.emissionsanalytics.com/news/do-no-harm - written by Emissions Analytics. The article supports the claim that Hybrid vehicles are better for the environment that full battery electric.

This is my critique of that article.

For full transparency, I am a long term Battery Electric Vehicle Owner.

So, in reviewing the article I find the following.

Firstly, there is a misdefinition of Pareto Efficiency.  

The article defines  that a system is Pareto Efficient when it is not possible to change the allocation of goods without harming at least one person.

Whilst I'm not sure about the phrase "Allocation of Goods" in this context,  Pareto Efficiency is defined where a system cannot be improved to a point beyond where economic changes no longer make one person better off without making one person worse off (https://en.wikipedia.org/wiki/Pareto_efficiency).     The definition used here seems to assume that it cannot make *any* person less well off - even if it improved others.  

Seeing as this is a fundamental pre-amble to thearticle, the fact that it is mis-defined it doesn't bode well!

So the article applies this to transport as :

"Interpreting that for transport decarbonisation, we can say that a change of powertrain can be a Pareto improvement if it is possible to improve all relevant aspects without disadvantage to someone. "

is also inherently wrong.  

It should be :"Interpreting that for transport decarbonisation, we can say that a change of powertrain can be a Pareto improvement if it is possible to improve all relevant aspects where more are advantaged than disadvantaged. "

I would concur that in the real world the advantage should be far higher than the disadvantage - but there is the concept of "not being able to make omelettes without breaking eggs"....

The article is based on two vehicles. The Kia Niro Full Hybrid and the Tesla Model Y.    

As someone massively into statistics, it is very dangerous to make conclusions from just two data points - it's easy to pick those points and wrongly extrapolate from them.  

I would contend that comparing a 140bhp 2WD small SUV costing <30k with a  larger 378bhp 4WD SUV costing nearly double isn't really a like for like comparison and it is hard to compare any of the figures quoted on that basis.

It is mentioned  in the article but glossed over  - comparing the "real world" choosing the largest selling battery electric vehicle - but it doesn't mention whether the Niro is the comparative largest selling Hybrid - and to be honest I don't know what is.  The fact that this is not  claimed  would suggest it isn't.   I understand the reason for the choice, but the article is about whether hybrids are a better option than EVS - not if the Niro is better than the Model Y.

The notion of emissions from tyres not contributing to air quality and toxicity is dismissed but  no evidence either way is shared.  

Similarly, the claim that many ev drivers see lower tyre wear than their previous ICE vehicles  is dismissed with an insinuation that this is unproven and may be due to a change in driving style.    

Taking the previous point - that the Model Y was chosen because it's the largest selling BEV, then it would be logical that if a move to EVs causes a reduction in tyre wear due to a change in driving style, then I would contend this also to be valid.  

I'm not familiar with the EQUA cycle, and there is  no reference to what it is.   I believe it is a test created by Emissions Analytics  but I can find no details of what the test is to be able to see whether it is a fair test or not.    

The test correctly ascertains that CO2 and NOx emissions for the Hybrid are infinitely higher than for the EV (of course!) but dismiss the NOx emissions as if they don't exist.   Whilst 2mg/km isn't much - that's still not zero and cumulates with miles driven.  

After dismissing the NOx emissions, the next section of the article is about tyre wear mass emissions.  As above, the Niro and the Model Y aren't like for like, so directly comparing isn't really valid.  

The summary refers to other articles which look at whole-life CO2 emissions of cars.    I've chosen not to critique these, but would pick one assertion - a 300g/kWH of CO2 for Battery Electric Vehicle Charging.  In the UK currently, the electricity grid as a whole generates 182g/kWH - nearly half the figure used.   The amount of electricity and CO2 in petrol/diesel production is conveniently ignored.

Overall, it would appear to me that the article is written to support a pre-defined conclusion, with the data points and statistics picked to support this.   It makes unsupported assertions, whilst dismissing other similar assertions.  It uses a test designed by the author and disregards some of the results as insignificant where in truth they may not be.

It doesn't mean that there may not be a truth to the article, but in my opinion, it doesn't stand up to scrutiny and doesn't pass the test of "convincing".

I'd like to see more data presented from more vehicles, along with comparisons using different tests (WLTP  for example).  

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Simon Verona

May 2023