Summary
We must urgently and rapidly decrease our use of internal combustion engine vehicles (ICEVs). It is important for environmental reasons, but also for our security -- we are currently heavily dependent on oil imports which are likely to become much more expensive (and quite possibly less accessible) in future. Burning oil for transport is unsustainable. We don't have time, and don't have the carbon budget, to replace our existing car fleet while remaining within 1.5℃ or probably 2℃ of warming.
In general, the EV-naysayers seem to think that we can just keep driving petrol cars forever, and the EV-yeasayers think that technology will work it all out so that we don't have to change our lifestyle.
I think they're both wrong: EVs, while considerably less-bad than ICEVs, are not good enough to prevent catastrophic climate change if we keep the current patterns of private vehicle use. We urgently need to find another way to decarbonise transport.
If you are going to buy a new car anyway, you should definitely buy an EV. However, if you do buy one you should still try and limit car use and share your EV with others -- this will mean that more value is obtained from its embodied carbon, and hopefully you can reduce the likelihood that others will buy new cars. The only way we are likely to meet our climate goals is by sharing EVs, so this aspect is essential.
Introduction
Currently, Australia has a plan to make transport sustainable. Our plan is something like:
Let's transition all vehicular transport to electric vehicles. These vehicles will be powered by renewable power which will decrease the climate impact and make transport sustainable.
The problem is that we've never really examined this plan to make sure that it will work. The main thing that most people focus on in this plan is the transition to private EVs. For these to work (by which I mean: be sustainable), we need to satisfy the following criteria:
- We need to be able to make EVs quickly enough to matter, so that we can quickly swap our existing car fleet over to EVs.
- The process of manufacturing/distributing the electric vehicles needs to remain inside the biophysical limits that we have. The most familiar of these limits is our remaining carbon budget -- however, water consumption and minerals availability are also very relevant.
- EVs need to be a large-enough improvement over ICEVs that we meet our sustainability objectives (eg. the total lifetime emissions of EVs need to be sufficiently less than ICEVs that we can get back "under the curve" of biophysical overshoot)
- People need to be able to afford them
Let's look at each of these points in turn:
1. Can we make EVs quickly enough?
Let's get a sense of what is needed. There are approximately 900 million cars in the world globally, and about 20 million cars in Australia. It's hard to get precise up-to-date numbers, but there are about 50000 EVs in Australia (about 1 car in 400), and between 20 and 30 million EVs globally (about 1 car in 500). Currently, rates of production are doubling annually. Thus, it seems plausible that we can make enough vehicles in the next decade if this trend roughly holds.
However, currently the average age of a car in Australia is about 10 years. Hence, this process of replacement will quickly slow as we saturate new cars with EVs. From when 100% of new cars are EVs, it will take close to a decade to replace Australia's entire car fleet. So, even though we might be able to make EVs quickly, people can't afford to buy new cars to replace their existing ICEVs. This suggests that a plan that depends on transitioning private transport to EVs is unlikely to work because we can't swap them over quickly enough.
It's also not yet clear how much utility remains in an EV after 10 years' use. People may not want them.
2. How does the process of manufacturing EVs fit within our biophysical limits? How does it compare to an ICEV?
Volvo have released some helpful data about EV vs ICE embodied carbon. Here are the data, which I sourced from https://www.volvocars.com/images/v/-/media/market-assets/intl/applications/dotcom/pdf/c40/volvo-c40-recharge-lca-report.pdf, page 25
I'm using these data to generalise to all EVs. We just want a rough estimate, so I think this is reasonable.
Carbon footprint of Volvo ICEV vs EV
In terms of manufacturing-related emissions. The tally looks like this:
- Volvo XC40 ICEV: 15.7 tons
- Volvo C40 EV: 26.4 tons
Volvo's report states that:
Although total emissions from all phases except the use phase of the C40 Recharge are higher than for the XC40 ICE, the C40 Recharge will over the span of its lifetime cause less emissions thanks to lower emissions in the use phase. Where this break-even occurs depends on the difference in GHG emissions from the production of the car, and how carbon intense the electricity mix is in the use phase.
For all three electricity mixes in the LCA [lifecycle analysis], the break- even occurs at 49,000 (100% wind), 77,000 (current EU average) and 110,000km (global average) respectively, all within the assumed life cycle of the vehicle (200,000km).
I often hear this concept of "break-even" used in this way. It is a mental error, let me explain why.
"Break-even" is bogus
When people talk about "break-even" they are making a comparison against something. In this case, the break-even is being calculated versus the purchase of a brand new petrol car. Volvo are essentially saying "assuming that you are buying a new car anyway, if you buy an EV instead of a petrol car, once you have driven 48000 km your emissions will be lower than they would have been if you bought a petrol car". (It's a bit like a clothing shop telling you you've saved $25 when you bought a new pair of jeans that were discounted -- in reality, you've only saved $25 if you were intending to buy the jeans at full price anyway).
Below is the graph showing, over time, how the four different scenarios play out:
 |
| Expected total GHG emissions of EV vs ICEV from Volvo. Note that producing a new Volvo X40 (EV) release approximately 26 tons of carbon dioxide, and producing a new Volvo |
The dotted line shows total emissions from a new petrol car, and the three solid lines show EV emissions which very depending on the electricity source from about 40% to 80% of the petrol car's emissions.
There are two scenarios that Volvo haven't considered:
- keep the existing petrol car and maintain existing driving habits
- keep the existing petrol car and drive less
(I can understand why Volvo don't want to encourage either of these options)
From Volvo's own data, we can estimate how these two scenarios would compare to the scenarios they explore. In the following figure, the first four rows of data are the same as in the image from Volvo's report. The bottom two are estimates, based-on Volvo's data.
If we compare against the scenario of "keep existing petrol car and existing driving patterns", then EV "break-even" looks like follows:
- global electricity average: 270000 km*
- EU electricity average: 190000km*
- wind power only: 125000 km
If we compare against the scenario of "keep existing petrol car and drive half as much", then EV "break-even" occurs like follows:
- global electricity average: never*
- EU electricity average: never*
- wind power only: 250000 km*
(I have put a star next to some of these, which indicates that payback will occur outside the warranty on the battery, which is typically 8 years or 160000 km)
These data are shown in the following exploratory time series model. The first four lines are the same as those in Volvo's figure (above). The additional two lines correspond to the "keep existing car" and "keep existing car, drive half as much" scenarios, as described. It shows the "break-even" between "keep car" and "new EV (wind)" occurring at 125000 km, and the "break-even" between "new EV (wind) and "new XC40" (petrol) occurring at 48000 kms.
Note that the "keep car, drive less" drives 1/2 the distance of the other scenarios (i.e. where the X-axis is labelled 200000 kms, it has driven 100000 kms). This is the least complex way to show the difference in behaviour in an easy-to-understand figure.
In other words, even if we buy an EV, drive the same, and charge it with 100% windpower, it takes 125000 km of driving until we have "repaid" the carbon emitted in its manufacture. In all other cases, environmental "break-even" will not occur during the warranty period of the battery.
To me, this suggests that two of the criteria listed at the start of this essay are not met by transitioning our private car fleet to EVs -- EVs are too costly (in environmental terms) to manufacture, and they don't help reduce carbon emissions enough (largely because of their environmental cost to manufacture). Because of their significant up-front environmental cost, we can't make enough of them to replace every petrol car with an EV.
EVs are great, but we just can't replace every petrol car with an EV.
3. How many cars can we replace with EVs?
As mentioned earlier, according to Volvo, the manufacture of each EV releases 26.4 tons of CO2.
There are 20 million registered cars on the road in Australia. In 2019, we had
less than 3.3 gigatons of carbon budget remaining to stay under 2℃ and less than 1.3 gigatons to stay under 1.5℃.
To replace those 20 million registered cars with EVs would release 20M*26.4 = 528M or ~0.5 gigatons of CO2, which is about half of our total carbon budget if we want to stay below 1.5℃ of warming.
That is almost 1/2 of Australia's carbon budget, just to manufacture a new EV to replace each existing ICEV.
It doesn't allow us to build the extra electricity generation capacity we will need to actually charge the EVs, it also doesn't help us decarbonise any of the following:
- energy,
- agriculture,
- medicine,
- manufacturing,
- mining,
- construction,
- waste disposal,
- sewerage treatment.
If we follow this plan, we will spend 1/2 our remaining carbon budget to partially fix a small part of our problem. Transport causes somewhere between 10-20% of Australia's emissions, so to spend half our carbon budget only reducing emissions for part of transport (passenger EVs doesn't fix freight, air travel, rail, busses) doesn't add up.
Again, the problem is not that EVs are not good -- the problem is that we can't replace every petrol car with an EV.
Conclusion
Let's revisit the four criteria I suggested at the start. Below are the requirements that must be met for EVs to be useful at weaning us from oil powered transport.
1. We need to be able to make EVs quickly enough to matter, so that we can quickly swap our existing car fleet over to EVs.
I think this is questionable. Even if it is possible for us to make them this quickly (which is uncertain) I don't think we can persuade people to buy them unless we have significant government incentives. These incentives would need to be means tested, and target people who are currently buying vehicles in the $500-$10000 range.
2. The process of manufacturing/distributing the electric vehicles needs to remain inside the biophysical limits that we have. Conceptually, the simplest of these limits to consider is our remaining carbon budget, but water consumption, minerals availability are also very relevant.
I think it is clear that we cannot manufacture enough EVs to replace all existing personal ICEVs and also decarbonise the other parts of our economy that we must if we are to keep within 1.5℃ of warming
EVs need to be a large-enough improvement over ICEVs that we meed our sustainability objectives (eg. the total lifetime emissions of EVs need to be sufficiently less than ICEVs that we can get back "under the curve" of biophysical overshoot)
I think it's apparent that the significant manufacture costs (carbon emissions) of EVs means that we don't avoid enough emissions if we swap our ICEVs for EVs and keep everything else the same.
People need to be able to afford them
This is unclear, but I think it unlikely without significant government intervention.
Solutions
So what should we do? The numbers are unequivocal -- we must drastically reduce the use of the private car, and it doesn't matter much whether the car is an EV or ICEV. We simply lack the technology to make private cars sustainable, and trying to cling to this idea makes meeting our climate goals impossible.
We must replace ICEV cars with EVs, but we can't replace every ICEV with an EV. Therefore, we need to come up with a way to reduce our car dependence (so that fewer trips need a car) and a way to share EVs (so that one EV can serve several people)
Therefore, we need to embrace public transport, walking, and cycling. These need to become our default transport options, saving private motor vehicles for the trips that actually need them. We need to make use of car sharing platforms (such as Car Next Door) to allow a relatively small number of EVs (maybe 1 million EVs -- where each EV is shared by 20 people) to serve all Australians (reducing the number of cars in Australia by 95%).
