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Comment by lorenzhs | Hacker News Reader

1l of gasoline stores 9.5 kWh [1]

Typical fuel efficiency is 20% (with up to 37%) [2], so let's be optimistic and say 31.5% because that will mean that we would get 3kWh of energy out of every litre of gasoline in energy that is actually used to move the car.

The efficiency of an electric vehicle is much higher, 86% was measured for the Tesla Roadster [3]. Assuming the same figure for a Model S, the effective battery capacity is 73kWh.

Thus, the 85 kWh battery of a Tesla Model S corresponds to a 24.3 litre (6.4 US gallons) gas tank.

In Germany, at 25ct/kWh, that's 21.25€ for the electricity or 34€ for the gasoline (at 1.40€/litre)

[1] http://www.wolframalpha.com/input/?i=%28gasoline+density+*+1...

[2] https://en.wikipedia.org/wiki/Fuel_efficiency#Fuel_efficienc...

[3] https://en.wikipedia.org/wiki/Tesla_Roadster#Energy_efficien...

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Here's a quick version for my local rates.

An EV will use about 300Wh of electricity per mile. This varies a bit depending on the car (a massive Model S will use more than a Leaf) and how you drive it, but it's a decent approximation. I pay about 13 cents/kWh. That makes my energy cost for driving an EV about 3.9 cents/mile. I believe that's 300Wh out of the battery, so you probably want to add another 10% or so for charging inefficiency, but I'm not sure exactly what the numbers are there so I'll leave them be.

My last car got 40MPG. At current local gas costs of $2.50/gallon, that's 6.25 cents/mile.

And of course, a lot of people think that current gas prices are anomalously low and won't last.

Interesting. That's obviously a good case number for an ICE vehicle (although it's pretty close to my current car at today's gas prices) but I hadn't realized that, from a "fuel" perspective, EVs aren't actually all that cheaper. Yes, 50% is a lot, but it's not multiples. (And, yes, there are some free charging options available but those aren't necessarily available to most people on a regular basis.)

I think most people would be quite pleased if gas prices were half of their current level (especially in Europe, where they are significantly higher than in the US). Plus you don't have to do oil changes ;)

According to the car computer over the last few days, my e-Golf got between 3.5 and 4.1 miles/kWh so your estimate is pretty close.

I did about 130 miles in the Model S yesterday and averaged 308Wh/mile. That also fits with a big one doing a bit worse than a smaller EV.

Tesla S has a range of 400 km. This makes the cost 5.31 € per 100 km. An average ICE car of the same size uses, let's say, 8 L per 100 km. The cost for the ICE is then 11.2 €. Twice as much. Don't forget that: you can charge at free stations, charge at a free supercharger, and you can charge the car at night when the electricity price is lower( 25ct is quite high btw ), while the price for the petrol is always the same.

you can charge the car at night when the electricity price is lower

Only if you have a garage. Plenty of people park on the street overnight, which is a non-trivial problem.

I'm not familiar with taxation in Germany. How are taxes on electricity and on gasoline? Maybe without taxes the costs are not too different, and taxes could be shifted from gas to electricity if gas cars usage plummets (they have to get taxes from something...)

Leaving aside the carbon tax issue, Germany in particular is less likely to shift the tax burden around as Germany has almost no domestic oil production.

I researched it. These data are both from 2014:

http://www.dw.de/german-electricity-price-is-half-taxes-and-...

"A typical household that uses 3,500 kilowatt hours of power per year pays about 85 euros ($113) a month for electricity." "About 45 euros, just over half the monthly total, is composed of taxes and special levies imposed by government."

http://en.wikipedia.org/wiki/Fuel_tax#Germany

"Fuel taxes in Germany are €0.4704 per litre for ultra-low sulphur Diesel and €0.6545 per litre for conventional unleaded petrol, plus Value Added Tax (19%) on the fuel itself and the Fuel Tax. That adds up to prices of €1.12 per litre for ultra-low sulphur Diesel and €1.27 per litre (approximately US$6,14 per US gallon) for unleaded petrol"

So petrol and electricity are taxed about the same but diesel is a little "cheaper". Chances are that taxes won't change much even if all of them switch to electric cars tomorrow.

How do you compare? Fuel in Germany is around €1.50, that means 75 to 85% of the final price are taxes, compared to 52% for electricity.

I'm using the prices in the Wikipedia page. I assumed they were correct in 2014.

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