Thread by @Sci_or_Fic

Tales of the unexpected.

I’m planning to buy a car.
I have been planning for an Electrical Vehicle.
So I would like to see how much CO2 I will save compared with a Diesel car. 😃

The cars weights the same.
Have the same tires.
They would have the same driver - me.
The driving pattern would be the same.

I will calculated the CO2 emissions for 1 TJ delivered to the wheels of both cars.
First I will quantify the essential parameters with references.
Then I will summarize it all in a spread sheet picture.
Finally I will celebrate the result.

First the diesel car.
“Passenger car diesel engines have energy efficiency of up to 41% but more typically 30%.”
en.wikipedia.org/wiki/Diesel_en…
The typically 30 % seems reasonable.

The CO2 emission can be calculated from the CO2 emission factor for diesel.

It is quantified in the EU regulation on the monitoring and reporting of greenhouse gas emissions Annex VI:
eur-lex.europa.eu/legal-content/…

The emission factor for diesel is 74,1 tonCO2/TJ

Next the electrical vehicle.
“EVs convert about 59%–62% of the electrical energy from the grid to power at the wheels.”
fueleconomy.gov/feg/evtech.sht…
Wow.
I choose 60 % without further consideration

Then I have to count in some transmission loss in the electrical grid.
“Generally speaking, T&D losses between 6% and 8% are considered normal.”
renewableenergyworld.com/articles/2007/…
7% seems to be a reasonable value for Transmission and Distribution loss.

Then a tricky part.
Where is the electricity coming from?
I live in Germany.
There is both solar, wind, nuclear, and coal power in the grid.

The following picture gives an idea about where the electricity will come from:
worldcoal.org/file_validate.…

As it seems, there is nothing more to get from wind and solar
Wind and solar are already delivering a maximum of what they can provide.
Nothing more to get
“Grid operators are obliged to purchase the entire quantity of renewable electricity with priority.”
worldcoal.org/file_validate.…

Further, the added electricity demand from my Electrical Vehicle cannot be provided from nuclear power because nuclear power stations seems to be catering for the base load, running with a fixed maximum output. There is nothing more to get from nuclear:
worldcoal.org/file_validate.…

As it seems, coal is the flexible electricity source. Coal power is the source that has to deliver the electricity to my electrical car.
(And maybe gas at high peaks, I will disregard that for a moment)

More than that, it is stated that
“the additional energy used to charge EVs is mainly provided by conventional power plants, and particularly by emission-intensive lignite plants”
wolfpeterschill.de/wp-content/upl…

So it actually turns out that:
Solar and wind got priority and is always delivering what it produces.
Nuclear is running at fixed maximum output.
Coal is flexible, and absorb the changes in demand.
worldcoal.org/flexibility-ge…

Ok, It seems reasonable.
If I replace my diesel car with an Electrical Vehicle, I have to count in that the electricity demand added by the new electrical car is delivered by a coal plant.
I don´t like it.
It will be hard to convince my wife and children about that.

It even seems that I have to count in that the electricity for my Electrical Vehicle would come from Lignite.
wolfpeterschill.de/wp-content/upl…

“the additional energy used to charge EVs is mainly provided by conventional power plants, and particularly by emission-intensive lignite plants“

So the CO2 emission will have to be calculated from the CO2 emission factor for coal.
It is quantified in the EU regulation on the monitoring and reporting of greenhouse gas emissions. Annex VI
eur-lex.europa.eu/legal-content/…

Emission factor for Lignite is 101,0 tonCO2/TJ

That is great. Now I got all the figures I need to compare the CO2 emissions of a new Electrical Vehicle with my diesel car.
It is simple high school math:
(I sincerely hope I don´t make an error)

Wow.
What a surprise
The CO2 emissions caused by my diesel car is 247 tonCO2/TJ
The CO2 emissions caused by a new Electrical Vehicle would be 489 tonCO2/TJ
(if there is lignite thermal power plants delivering electricity to the grid.)

Can that really be true?
It seems so.
Her is a peer reviewed paper that essentially comes to the same conclusion:
wolfpeterschill.de/wp-content/upl…

So, it seems that if I choose an Electrical Vehicle rather than a diesel car:
The CO2 emissions would double -
The CO2 emissions would increase by 100 %

I need a drink.

(1TJ is a unrealistic amount of energy.
However, the amount of energy does not matter since I am going to compare the CO2 emissions for an Electrical Vehicle with a diesel car for the same amount of energy. I use 1 TJ since the CO2 emission factors are given as tonCO2/TJ )

@threadreaderapp unroll