Posted by: Valentin Berceanu | November 16, 2016

20161116 – A quick analysis of the real global warming impact of the Tesla Model S

(Versiunea în română la: http://wp.me/pIEsf-jy)

All the sources are included below for reference.

I am not going to dispute any claims about the anthropological aspect of global warming or climate change. I’m going to play the game by their rules and and use their numbers and try and provide an accurate analysis of the impact a Tesla car has over an average gasoline vehicle. The reason why I’m doing this is because there is a lot of sleight of hand done with the statistics by most studies looking to promote the car as being “green” and green energy as being the way of the future. Make no mistake about it, our society, ever since it first climbed out of the caves became a society dependant on energy generation. From slave powered pumps and mills to electric turbines society has always required energy to function. Today there seems to be some sort of equivalency between energy and electricity (most likely has to do with conservation of energy and this being the most efficient form of transport for energy) and if we are to find our path into future horizons, we will require a cost-effective, environmentally friendly way of generating electricity. But in this need of ours, we must remain skeptical and look at the data over the propaganda. Why? Because the entire weight of the propaganda apparatchik of the USSR couldn’t feed even one starving citizen and the whole show came crumbling down because of it. Tesla hails itself as either more cost-effective, either more environmentally friendly than the average cars so it’s warranted to take a deeper look at what the numbers actually say.

First a look at the claims (from [1]):

Figure 1

Figure 1

The most fuel efficient, non-hybrid car of 2016 (a comparable sedan class vehicle) versus the best Tesla Model S in terms of fuel efficiency. Look at those numbers, 101 vs 32… You’d say the battle is over before it even began, but this is what I was talking about with the statistical sleight of hand. We’re interested in looking at the overall environmental impact and the truth is that the Tesla Model S has a much larger environmental footprint up front than a regular gasoline car. This is because of the different components that go into the production of the battery and the power conversion systems. Luckily there’s a very favourable study that came out in 2015 from the Union of Concerned Scientists that is looking to address this point [2]. The study findings are that there is a 53% reduction of emissions over the lifetime of a Tesla (BEV) when compared to a regular full-size car over its lifetime even after accounting for the increased emissions during the manufacturing process.

Figure 2

Figure 2

Case closed, right? Well, wrong. Because there is some more sleight of hand done even in this study because they get to define the lifetime and operating parameters of both vehicles over that lifetime and this directly affects the length of the grey bar. But this study is an excellent starting point because it brings enough raw data to the party to get us started. The essential of which are the difference in emissions which can be found on page 21:

screen-shot-2016-11-12-at-16-01-31

Now they are also pointing us to which state in the US is the most favourable for Tesla due to the mixture of energy sources and that is California (page 23).

screen-shot-2016-11-12-at-16-01-52

This gives us the challenge to figure out the emissions generated in the production of the energy needed to power the Tesla battery. In order to do that we need to find the breakup of sources for energy generation in California and the corresponding emission quantities which we then combine according to the power mix ratio and we have the average emission per kWh of energy. Below is the calculation snapshot and underneath will follow the sources for those emission numbers:

Figure 3

Figure 3

The sources for percentages are taken from Wikipedia [3].

Table 1

Table 1

The emissions for carbon are converted into grams from pounds [4] by selecting the cleanest type of coal. The same applies for natural gas.

Table 2

Table 2

The emissions for biomass are taken after processing the numbers in the slideshow of the presentation done in 2010 at UC Berkely [5] about biomass energy generation in California.

4

Table 3

Table 3

Ton to grammes and MegaWatt to kiloWatt transformations are applied to get the number from above.

For the unspecified others, this is untraceable energy, most likely imported from Mexico. Since it’s impossible to determine emissions for this type of energy, I have decided to arbitrarily assign an emissions percentage somewhere in between the cleanest fossil fuel (natural gas) and the second cleanest (coal) at 700 grams per kWh. If this energy is really coming from Mexico then, in all likelihood, this energy is much dirtier to generate, but we’ll live with this figure. If we look back to Figure 1 we’re going to discover that the Tesla is expending 33 kWh/100 miles therefore we can calculate the equivalent emissions in California for the power expenditure at 14226.92898 grams of carbon from CO2 emissions per 100 miles.

Let’s find out the corresponding emissions for the same distance of the Mazda. In order to do that we look up the emissions guidelines from the EPA [6].

6

This means the Mazda emissions for 100 miles traveled at a fuel efficiency rating of 3.1 gallons per 100 miles (Figure 1) is 27549.7 grams of carbon from CO2. Now let’s take this a little further and include in the analysis “the average 2016 gasoline sedan” which has a fuel efficiency of 4 gallons per 100 miles (also Figure 1, 25MPG ). This type of vehicle would emit emissions of 35548 grams of carbon from CO2. In continuing this analysis we will pit the Tesla against this generic car model in order to better account for the distribution of purchasing (nobody’s forced to buy a Mazda 6, right?). The difference in emissions is a simple calculation which we will normalise to KG/100 miles for ease of reference. This difference is 21.321 KGs of carbon per 100 miles. This means that the Tesla will break even after (accounting for the difference “at birth” of 6 tons – 6000 KGs) after 281.412 100 miles cycles. For an easier reference this translates linearly into 45279.151 kms. Look at that number again. It’s not huge, but it is significant. It’s also never brought up in any discussion about the Tesla. But the question becomes, after this break even point, just how much pollution are you “sparing” the earth by driving a Tesla over the average 2016 car? We already answered that, in Kgs/100 miles, but let’s normalise it for 1000 Kms. The answer is that a Tesla will be responsible for 132.511 (one hundred and thirty two point five-one-one) Kgs of carbon less per 1000 Kms traveled than the average 2016 model.

That seems like something really significant, until we put a price on it. For that we’ll just pick up the info from New Zealand emissions trading scheme and their unit prices [7] and being generous we’ll pick up a price of 20 New Zealand Dollars for a ton of carbon.

7

I’d have taken the unit price from the US but I just couldn’t find it so instead I converted the 20 NZD to 16.62 USD. This results in an value of the economy Tesla generates per 1000 Kms of 2 dollars and 20 cents. And this only happens after you drove it for over 45000 kilometres to achieve parity with gasoline burning cars. Whoopdy doooooo….

Sadly, this isn’t the end of it. Because after looking at the Tesla site I realised that there’s another dimension to all of this. We ran the numbers for the consumed power that a Tesla expends over the course of 100 miles, but the truth is that there is a difference in efficiency between the power that is dispensed by a rechargeable battery and the power that is expended to attain that charge. Let me put it in simpler terms, the power the Tesla charger consumes to generate a battery charge of 33kWh is larger than 33kWh. How much larger, depends on the power source, as evidenced on the Tesla site [8] – these numbers are given helpfully in miles generated per hour of charge:

8

Now, in order to calculate the amount of kWh necessary for a charge that would sustain 100 miles we do some simple arithmetics and come up with the following highlighted results:

9

Upon plugging these new kiloWattHour consumptions per 100 miles the numbers determined above change as follows:

10

And continued over the calculations from above:

11

This means that if you charge your Tesla from an RV camper charger it’ll take you over 46000 kilometres to offset the initial extra pollution and then your carbon offset will be valued at 2.14 USD per 1000 kilometres. If you charge your Tesla from a newer style wall socket it’ll take you over 59000 kilometres to offset the initial extra pollution and then your carbon offset will be valued at 1.67 USD per 1000 kilometres. And ultimately, if you charge your tesla from the current standard power outlet in the USA the numbers will be over 62000 kilometres and 1.59 USD per 1000 kilometres. And this is for California, the cleanest energy generating state in the entire USA. These numbers are raw numbers, they are not dependant on a certain amount of miles per car lifetime, but rather calculated from the start. The assumptions that have been made were in favour of the Tesla (no battery ageing and loss of efficiency upon charging, the cleanest coal and the cleanest biofuel taken into generating the electricity, a median – between coal and natural gas – assignation of emissions to the unspecified component, one of the highest unit prices for coal emissions trading of the past 6 years, comparison of best Tesla model against average gas model), but the result is showing that there’s a lot of hype and very little substance when it comes to the actual reduction of carbon footprint and the value saved in the emission reduction trading schemes implemented under the Kyoto accord.

But this is the US. Their energy system is a dinosaur. The technology is antiquated, surely, in Europe the emissions situation is better. Take a country like Denmark, for instance, a media darling in recent times for their usage of renewable energy. Surely, the numbers for Tesla would look different in a country like Denmark!

So, we go hunting for the energy generation sources for Denmark and we find them at Mecometer
based on data collected by the Worldbank: World Development Indicators [9]

12

What’s missing from here is biomass which is included in renewables, but after a search on Wikipedia [10] we find out that

13

which translated with the algorithm determined above for converting Biomass to energy and taken out of the total amount of energy generated (shown by Mercom [9] to be ) we find the proportion of 6.9% generated from biomass. We use the best oil in terms of emissions from Table 2 and the breakdown for Denmark energy looks like this:

15

If you think that there’s a problem because the result for California was 432 grams, yes, you’re right. Turns out energy generation in pristine Denmark is “dirtier” than in California. But, let’s do the numbers anyway and check the damage.

screen-shot-2016-11-06-at-01-51-54

The good news is that the European standard outlet power is as effective at charging as the US RV camper chargers, but because the power is dirtier it takes 53760 Kilometres for the Tesla to break even against the same average 25MPG sedan model from above and the money saved after that in Carbon Emissions per 1000 Kilometres are 1.86 USD.

So what’s the conclusion? Is the Tesla easier on the environment than the average gas guzzler produced in 2016? Only after a significant amount of kilometres of driving it around, and even then only by a marginal amount. Tesla is riding a popularity wave of “green energy” and “green technology” and even though they’re not making any unsupported claims themselves about the carbon emissions impact of their cars, there are plenty of “scientists” and statisticians out there that fudge the numbers to present Tesla in a much more favourable light that it should be. All this is done in the name of fighting “climate change”. Is it really a good thing that we’re lying to ourselves with regards to the effectiveness with which we ARE actually fighting? I wonder…

links:
[1] – http://www.fueleconomy.gov/feg/Find.do?action=sbs&id=35982&id=36126
[2] – http://www.ucsusa.org/sites/default/files/attach/2015/11/Cleaner-Cars-from-Cradle-to-Grave-full-report.pdf
[3] – https://en.wikipedia.org/wiki/Energy_in_California
[4] – http://www.eia.gov/tools/faqs/faq.cfm?id=74&t=11
[5] – http://ucanr.edu/sites/WoodyBiomass/files/79012.pdf
[6] – https://www.epa.gov/sites/production/files/2016-02/documents/420f14040a.pdf
[7] – https://en.wikipedia.org/wiki/Emissions_trading
[8] – https://www.tesla.com/models-charging?redirect=no#/outlet
[9] – http://mecometer.com/whats/denmark/electricity-production-by-source/
[10] – https://en.wikipedia.org/wiki/Energy_in_Denmark#Biomass

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