EVs are (not) evil
This time it’s not about antennas or anything related to radio-frequency, this time it’s a, probably controversial, topic that I’ve been looking and discussing with some folks for at least a year, and it is related to Electric Vehicles (EVs). As an electronics engineer, I am a technology advocate in general, however, with regards to EVs, I don’t like the way they’re being advertised as the grand solution for mobility in detriment of everything else, and specially I don’t think the best way to make EVs with environment in mind is the EVs the automakers are developing, I honestly believe EVs are a green solution for mobility, but I think most automakers are perverting the concept. I warned you this post was a controversial!
I’ve been, for a while, searching for information online regarding CO2 emissions in general and trying to validate my thesis that EVs, as being currently developed and marketed by the major auto brands, are mostly aberrations and are not entirely green, as they could actually be. But then a spark to commit to finish this post happened. A few days after I started writing this post (yeah, I kinda quit on it, but decided to get back on after a long time), some news came out about the step down of Toyota’s CEO Akio Toyoda as chief executive. The issue becomes relevant because Akio Toyoda was not entirely convinced by the electric vehicle revolution and that was making Toyota’s stakeholders not very happy. Toyota was a pioneer in electrification of cars, with many years of development of hybrid engines, so it’s clear that Toyota has always had an interest in creating more sustainable solutions, plus in the recent years they have been the main drivers for hydrogen powered vehicles, which might as well be part of future mobility solutions. It seems this decision to step down might have been triggered in consequence of Toyota’s chief scientist Gill Pratt presentation at the World Economic Forum in Davos, where he spewed some bull** about lithium scarcity in the world and how it was best to bet on hybrids then full EVs… well that’s not cool either. It seems their angle was to try to advertise for hybrids, which are Toyota’s biggest market, maybe because they’ve been lagging in the EV world, even though Toyota already released a full EV and it’s looking awesome. At this point I don’t really know what’s going on in their minds, so I’ll try not to make any further assumptions.
Still, there are a few points to consider about EVs and I’ll try to convey my point about those in this post. I’m certain that the move forward is not to be full-EV nor anti-EV. Taking one of these positions is pure fanatism and nothing good can come out of that.
To show that EVs, as they’re being developed at the moment are not the way to go, let’s start by looking at the emissions from these. One needs to realize that electricity production accounted for 32% of total emissions of CO2 in the USA in 2021, right of the bat one can see how the assumption that using electricity to move vehicles may have an issue, if you factor in the increase in electricity needs due to the increase of electric vehicles circulating and the fact that the easiest way to scale electricity production are the fossil fuel plants or nuclear power plants with all the issues that come with that. Then you can already see the problem appearing, but let’s dig deeper…
Let’s try to estimate the amount of CO2 an electric car produces to drive for 100 km. Now this depends on many different factors, such as the car itself, the country you’re talking about, the sources to produce electricity used in that country, etc.. I’ll pick one car and use the USA as an example for calculations.
And what better model for this demonstration than the best-selling Tesla model Y, the most widely sold EV in 2021 and 2022
The Tesla model Y is a 4.75 m long, 2.13 wide vehicle, with 455 HP of peak power, which is more than any supercar of the 90’s, 494 Nm of Torque, which is more than a cargo van like a Mercedes Vito (400Nm) and 2066 kg of dry weight, again roughly in the ballpark of a cargo van like the Vito, which is a commercial vehicle designed to transport goods. If you don’t find that obscene yet, let’s crunch the numbers.
The Tesla model Y long range has a 75 kWh battery capacity, with which it claims to have a range of 530 km, meaning the average consumption is 75kWh / (530/100) = 14.15 kWh per 100km of travel.
Looking up the certifications for the Tesla model Y in the EPA (Environmental Protection Agency), among many other documents, one can find this one, where there’s data about charging and depletion tests performed on the car, and in page 9 for instance we can see that for the long range model, a total of 92.213 kWh was used to completely fill 81.052 kWh of battery capacity and this was used to travel a total of 376 miles (605 km), which means that the charging efficiency of the battery is roughly (81.052 / 92.213) x 100 = 87.90%, or rather that ((92.213 - 81.052) / 81.052) x 100 = 13.77% of power is loss during charging. Also to note, this was done in climate controlled environment with brand new batteries and a brand new car. This means that under normal conditions, where temperatures and humidity are not ideal and with ageing batteries and ageing engine, suspensions and tires, these efficiencies start to get worse. Plus, high voltage chargers were used, if normal plug charging is used, the efficiency of charging can drop even further to as low as 60%, so in the worst case scenario, we’d be looking at 113.4 kWh to charge the Tesla battery. There’s more info on charging efficiencies in this report from the US Department of Energy.
Let’s take the values from the certification and in the best case scenario it drove for 658.2km with 92.213 kWh energy used, while in the worst case scenario it drove for 408.7 km, where it was subject to colder temperatures. In real usage scenario, the temperatures vary, the driving conditions change even more drastically, which means the range will in reality be something in between, which translates to 533.4 km, quite in line with the estimated average range offered by Tesla (maybe they calculate the estimated range from these measures?). However, with 92.213 kWh total power to travel 533.4 km, this means an average consumption of 92.213 kWh / (533.4 / 100) = 17.23 kWh/100 km, or 0.1729 kWh per km.
With these numbers, let’s see how much CO2 is released to produce said energy. If we take the USA numbers for reference, then 61% of the electricity generation is from Fossil Fuel burning, where from this 38.4% is from Gas and 21.9% from Coal burning. Other sources and their corresponding emissions per kWh energy generated can be found in the following table:
| Fuel source | CO2 emissions per 1kWh energy | % to generate electricity (in USA) | CO2 emissions adjusted to % (g) |
|---|---|---|---|
| Coal | 950 g | 21.9 | 208.1 |
| Natural gas | 350 g | 38.4 | 134.4 |
| Biomass | 350 g* | 1.3 | 4.6 |
| Solar | 60 – 150 g | 2.8 | 1.7** |
| Wind | 3 – 22 g | 9.2 | 0.3** |
| Nuclear | 6 g | 18.9 | 1.1 |
| Hydro | 4 g | 6.1 | 0.2 |
| Total: | 350.4 |
*Assumed the same emissions as Gas plants since the essence is the same, should not be wrong by much. **Assumed the most optimistic (least emissions) scenario.
If the electricity of the Tesla Model Y was entirely generated from Coal power plants, it would be equivalent to it emitting 950 x 0.1729 = 164.25 g/km of CO2, which is more that an equivalent hybrid car. Fortunately, electricity production from coal is less than a quarter of total electricity produced (in the USA). So, if we account the CO2 emissions considering the different sources production as per the previous table, the Tesla Model Y would emit roughly 350.4 x 0.1729 = 60.58 g/km of CO2, which is less than half of said hybrid.
For comparison purposes let’s look at the Toyota RAV 4. Why the RAV4 you ask, well, first I started this post talking about Toyota so it’s only fitting I compare to one of their models, also the RAV4 is a comparable car in terms of size and utility and the RAV4 has been one of the best-selling crossover/SUVs for the past years, so from my point of view, the model Y and the RAV4 are two reasonably comparable choices.
Engine performance is not comparable, the Model Y has much more horsepower and torque than the 2.5L hybrid engine of the RAV4, but that just goes to show how ridiculous that is. Nevertheless, the RAV4 lets you go to nearly 200 km/h, while the Tesla caps you at around 150 km/h of max speed and even then if you travel at that speed for long, you won’t reach those numbers of efficiency/range, so all in all it’s hard to compare combustion and electric cars, but bear with me with this comparison.
The Toyota hybrid engine has emissions rated at 130 g/km, which is quite impressive for such a sizeable car. That’s a little more than double the calculated emissions for the Tesla Model Y, but again, the variation is probably going to be bigger for the EV when compared to the hybrid engine. The emissions for the hybrid are going to vary roughly 10% depending on driving style and climatic conditions, which brings the worst case to 143 g/km of CO2 emissions. But for the Tesla, in the worst case, as mentioned above, the range reduces to 408.7 km, and most probably even lower, because driving speed is not maintained constant, there’s different circumstances in traffic and the AC in the car will be used, but even considering the 408.7 km, brings the average consumption to 92.213 kWh / (408.7 / 100) = 22.56 kWh/100 km, or 0.2256 kWh per km, increasing the CO2 emissions to 79.05 g/km, and if we consider the worst charging conditions, then we’re looking at 113.4 kWh / (408.7 / 100) = 27.75 kWh/100 km, or 0.2775 kWh per km, increasing the CO2 emissions to 97.2 g/km, which closes the gap to the combustion engine emissions. The real CO2 emission number of the Tesla will be somewhere in between those 60 to 100 g per km.
Another important factor to bring in is the CO2 emissions to produce the fuels for electricity generation, and of course one needs to also add in the CO2 emissions from refineries to produce petrol and diesel for the combustion cars. What’s called the ‘Well to Wheel’ (WTW) or ‘Well To Tank’ (WTT) emissions ratio.
(put well to wheel or well to tank image: https://joint-research-centre.ec.europa.eu/sites/default/files/styles/oe_theme_medium_2x_no_crop/public/2016-12/wtwanalysis.png?itok=q2cDsrjC)
While I was researching for this post I came across a youtube video with this exact comparison between the Model Y and the RAV4. Which was quite shocking because I had like 70% of this post already written and thought that all this was going to shambles, but then I realized that some things were left out, as I’ll explain right after, and besides my post and that video are not trying to convey the same message, as my take is not to convey that the hybrid is nearly as green as the EV. It may seem like so, so far, but it is not, keep reading!
So, if one considers the WTT ratio for petrol, according to that video it would be in the ballpark of 2.827 kg/l, another source puts it it at 3.140 kg/l, however, it also claims one should add 30% to the announced emissions from engine combustion to get a value close to the WTT ratio and if we consider 3.140 kg/l on the RAV4 that would mean an increase of 60%, so something is not entirely right, hence, I’m going to go ahead and consider the 2.827 kg/l. This means the RAV4 would actually emit (considering 6.6 l/100km of fuel consumption), 6.6 * 2827 / 100 = 186.58 g/km of CO2 (43% more than driving only emissions), which means it emits two times more than the Model Y.
At this point one can conclude that, effectively the EV emits much less CO2 when compared to even a reasonably efficient hybrid vehicle. And, this is using the CO2 emissions of electricity production in the US, because if we factor in France for instance, where nearly 80% of its electricity is produced from nuclear and hydro plants then the gap is even bigger and EVs are definitely much greener in France. But such is not the case for China, where most of the electricity production is fueled by coal. Therefore, EVs polute as much as a regular petrol car in China!
Now, with the shift in electricity production around the world towards greener sources, with increase efficiency of the EV cars, definitely the EVs will be a much greener means of transportation. But that should also bear in the shoulders of the automakers, especially Tesla as the main driver of this transformation, by producing more efficient cars. Not simply rely on the fact that they’re electric, but make efficient transportation means. The size, weight and power of the current models are not efficient from a transportation point of view. And when you think that most cars in eastern cultures are driven carrying on average less than 2 people, then moving 2 tonnes of vehicle around just to carry 1 person is simply ludicrous. Of course people should be re-educated on that matter, but the automakers could also do something about that.
In summary, I do believe EVs are and should definitely be part of the picture for future mobility. EVs should be one solution, but that’s the key, they should be one, among many solutions for mobility. Unfortunately, EVs are being proclaimed as the saviors of the environment and pushed aggressively for sales in detriment of promoting and investigating on other possible alternatives, but after what I’ve tried to convey with this post I hope that you’ve realized that’s not entirely true, and hence, our politics should act more responsibly (yeah right, who I’m a kidding…) and actually create a conjecture to promote a safe and greener future and not simply brush off this topic on an east solution, that will probably end up biting us all in our bottoms in a few years.
Well that was some gloomy post, I promise to get back to radio next time.
Stay tuned!
Sources used for this post: Eletricity production accounts for 32% of total CO2 emissions
CO2 emissions to produce coal, gas, oil