Saving money with the Roadster

[richkae]

When people talk to me about saving money on gas with the Roadster, its usually a joke.
I usually respond that it will take forever to justify the Roadster due to saving money on gas, but future electric cars will be better blah blah.

Suppose you compare the Roadster to a $60000 20mpg premium burning sports car.
You drive 12000 miles per year. Premium gasoline is currently about $4 per gallon and increasing at 8.5% per year. Electricity is currently 11 cents per kWh and increasing at 4% per year. ( Seattle area numbers. )

The Roadster costs $50000 more than the gas car, and you'll need to buy 2 battery replacements that I am guessing will be $15000 each ( one at ~9 years, one at ~18 years ).
For a total of $80000 more than the gas car. ( This actually ignores the almost $13000 in tax savings over the gas car )
If you finance that additional up front money and the first battery replacement at 3.8% you end spending $104000 over 18 years.
It takes about 18 years to save $104,000 on gas.

In 18 years the Roadster will still have value, but the gasoline car will be so expensive to operate it will have near zero value.
You likely will have spent a lot less on maintenance as well.

 

[benji4]

Actually, driving 12,000 miles per year at 20mpg for 18 years would cost $54,000 assuming $4 per gallon gas. By comparison, the electric bill for a Roadster over the same distance would be around $10,000 at 10 cents per kWh and averaging around 250 Wh/mi. Not too bad actually... lots of money saved on oil changes and the like as well. Tires on the Roadster will be costly of course. Tough to justify the Roadster on the basis of cost savings alone, but perhaps the wildcard might be a much higher residual value on the Roadster after that period.

 

[S-2000 Roadster]

The year before I bought my Tesla Roadster, I spent a total of $500 on gas. That's because I work from home.

I also spent the same amount of money on tires before the Tesla - because I seem to only buy 2-seater sports cars with high-traction tires.

The Tesla Roadster will never pay for itself in dollars, but by the true definition of capitalism I feel like I am better off with the Tesla than I would be with the money, so I'm coming out ahead in my own estimation. I don't think anything will improve if we make every decision based on dollars and picking the cheapest option every time. In some instances you simply have to be willing to pay for cutting edge technology if you're unwilling to accept the old technology at any price.

 

[Mischa]

current situation in germany:
Price for Gas: 7,9 US$/gallon
Price for Diesel: 7,34 US$/gallon
Price per KW/h: 0,25 US$

I changed my Audi A6 3.0 Diesel with the Roadster. Keeping the unpayable fun beside, i save more than 5 US$ per hours i sit in my car!
Ok, i dropped the price for tires from my calculation - that belong to fun

 

[W.Petefish]

I save $640 per month. (adjusted for electricity costs, not including maintenance of other said vehicle at $100+ every other month in air filters, oil, and oil filters)

 

[tennis_trs]

...averaging around 250 Wh/mi...

Is 250 Wh/mi fairly realistic? My average over 26,000 miles is about 415 Wh/mi (measured by the meter on my dedicated circuit in my apartment building's garage). I wonder how much variance there is, over many miles, between different owners with their different uses (i.e., driving styles, types of typical drives, etc.) of their Roadsters.

 

[Robert.Boston]

Is 250 Wh/mi fairly realistic? My average over 26,000 miles is about 415 Wh/mi (measured by the meter on my dedicated circuit in my apartment building's garage).

Because you're measuring input into the system, you are including losses during charging. Your number is useful if you're installing PV to meet your energy needs, but the after-loss number is what we need to know how many miles a battery can provide.

 

[benji4]

Is 250 Wh/mi fairly realistic? My average over 26,000 miles is about 415 Wh/mi (measured by the meter on my dedicated circuit in my apartment building's garage). I wonder how much variance there is, over many miles, between different owners with their different uses (i.e., driving styles, types of typical drives, etc.) of their Roadsters.

Yes, you're right, it is really too optimistic when you look at wall to wheel charging and the fact you do loose some charge even with the car just sitting there inactive. Unless you happen to be lucky enough to live in an area where electricity is 6 or 7 cents per kWh, your savings will be somewhat less than I stated. So let's look at case using more realistic parameters for someone who drives 10,000 miles per year, and again assume an average of 20mpg for the gasoline-powered sports car:

1) Gasoline-powered sports car
Miles per year = 10,000
Avg. MPG = 20
Cost of gasoline = $4.00
Total fuel cost per year = $2,000

2) Tesla Roadster
Miles per year = 10,000
Avg. Wh/mi = 415
Cost of Electricity = 15 cent kWh
Total fuel cost per year = $625

Still not bad as the Roadster owner saves around $1,400 per year on fuel costs. Just the cost of tires alone eats into that pretty quickly though! Note that Mischa, however, ends up saving a lot more. With $8 per gallon gasoline fuel costs would be around $4,000 per year, and even with the 25 cents per kWh he pays for electricity the Roadster still only costs him around $1000 per year and he saves $3000.

Where it gets interesting would be a case where gasoline costs $4.00 per gallon and electricity is 25 cents per kWh. In that case, if you are willing to put up with the performance of a 50mpg Prius rather than a sports car, gasoline for the Prius ($800) actually costs less than the electricity to power the Roadster ($1000). I believe in the U.S. Hawaii is currently the only state with rates that high (around 28 cents per kWh) thus making the Roadster more expensive to drive than the Prius.

 

[tennis_trs]

Because you're measuring input into the system, you are including losses during charging. Your number is useful if you're installing PV to meet your energy needs, but the after-loss number is what we need to know how many miles a battery can provide.

This thread is regarding real expenses, including energy costs, to operate a Roadster vs other vehicles.

 

[augkuo]

Here in California, you're allowed to use the HOV lane even if you only have one person in the car so I would figure in the amount of time saved as well.
That alone is much more valuable than the gas savings!

This thread is regarding real expenses, including energy costs, to operate a Roadster vs other vehicles.

 

[richkae]

Actually, driving 12,000 miles per year at 20mpg for 18 years would cost $54,000 assuming $4 per gallon gas. By comparison, the electric bill for a Roadster over the same distance would be around $10,000 at 10 cents per kWh and averaging around 250 Wh/mi. Not too bad actually... lots of money saved on oil changes and the like as well. Tires on the Roadster will be costly of course. Tough to justify the Roadster on the basis of cost savings alone, but perhaps the wildcard might be a much higher residual value on the Roadster after that period.

You didn't read the part where I say gasoline starts at $4 per gallon and increases at 8.5% per year. Thats what it has done in the U.S. averaged over the last 10 years. If you extrapolate that out - after 18 years gasoline cost is up to $17.37 per gallon.

 

[richkae]

The Tesla Roadster will never pay for itself in dollars, but ...

I assumed that was true as well. Then I did the math and its not true, it only takes 18 years - purely on the cost of fuel if the price trend of the last 10 years continues.

 

[benji4]

You didn't read the part where I say gasoline starts at $4 per gallon and increases at 8.5% per year. Thats what it has done in the U.S. averaged over the last 10 years. If you extrapolate that out - after 18 years gasoline cost is up to $17.37 per gallon.

Oh, sorry about that... You might figure that electricity prices will rise at about the same rate as gasoline though. Let's hope that neither one of them continues to go up 8.5% per year! A lot more people will be walking or taking the bus....

 

[richkae]

I looked at my last 10 years of electric bills and the cost of electricity has risen about 4% per year.
I could have used a more pessimistic number for that, but it wouldn't really change things too much.

I do believe that the trend can't continue, because before we get to that point demand will be severely affected.
However its worth noting that in 7 years the oil usage of China will pass that of the US, and the ability of US consumers alone to affect prices will be greatly diminished.

 

[Dragon]

In Italy the gasoline price just went up to 1,70€/l. That would be 8,60 $ / gallon. So with an electric car you're doing fine.
The bad thing is, that there is coming a new tax for cars with over 185 KW. That would cost me 540 € next year. My only hope is, this doesn't apply to electric cars... :crying:

 

[S-2000 Roadster]

Still not bad as the Roadster owner saves around $1,400 per year on fuel costs. Just the cost of tires alone eats into that pretty quickly though!

It seems that these numbers will vary widely from driver to driver. I only spent $500 on fuel last year, so I can't save more than that. Also, I already mentioned that I buy ultra high performance tires for my gas cars, too, so Tesla Roadster tires won't really eat into the hypothetical savings for me.

By the way, my Tesla Roadster replaced a daily-driver gasser that is 21 years old. It would be nice to think that I could keep my new car that long and have it pay for itself, but I just don't drive enough to save that kind of money.

Keep in mind that the first 'R' is Reduce (you know: Reduce, Reuse, Recycle). Sometimes the best way to save money on your vehicular costs is to organize your life style so that you do not need to drive so much. Not to get off-topic, but when I interview for jobs I have often been able to convince people that telecommuting is a valid option for high-tech workers.

 

[hcsharp]

The only truly accurate way of analyzing this question is to use net present value calculations. That takes into account your cost of capital, among other things. It also allows you to put a value on other intangible items such as satisfaction of knowing that you are not creating emissions, value of the HOV lane, etc.

Using NPV calculations with the numbers you provided, the Roadster appears to win on cost savings alone in many scenarios. The NPV of the gas alone is around $70-80,000 depending on the discount rate. The discount rate is generally your cost of capital or lost opportunity cost. Using your suggested rate of 3.8% for the battery, the gas is worth about $70,000 today. That is what you would have to borrow at 3.8% interest to exactly pay for 18 years and 2 days of gas. BTW you would only need one battery replacement to reach 18 years. And according to the GAO, the average repair cost for an ICE vehicle has about the same NPV as the battery replacement.

If you add in a modest value for no emissions, HOV lane, coolest car ever, the Roadster wins hands down. Or in my case if you drive 15-20k mi per yr and your cost of capital is only 2.55%, (NPV of the gas becomes $132,000), and your power is almost free, the Roadster is a pretty sweet deal next to the other car!

Unfortunately I don't think gas will go up any faster than the general rate of inflation. That's a pretty lonely position around here. Even the GAO disagrees with me.

When people talk to me about saving money on gas with the Roadster, its usually a joke.
I usually respond that it will take forever to justify the Roadster due to saving money on gas, but future electric cars will be better blah blah.

Suppose you compare the Roadster to a $60000 20mpg premium burning sports car.
You drive 12000 miles per year. Premium gasoline is currently about $4 per gallon and increasing at 8.5% per year. Electricity is currently 11 cents per kWh and increasing at 4% per year. ( Seattle area numbers. )

The Roadster costs $50000 more than the gas car, and you'll need to buy 2 battery replacements that I am guessing will be $15000 each ( one at ~9 years, one at ~18 years ).
For a total of $80000 more than the gas car. ( This actually ignores the almost $13000 in tax savings over the gas car )
If you finance that additional up front money and the first battery replacement at 3.8% you end spending $104000 over 18 years.
It takes about 18 years to save $104,000 on gas.

In 18 years the Roadster will still have value, but the gasoline car will be so expensive to operate it will have near zero value.
You likely will have spent a lot less on maintenance as well.

 

[Mischa]

hmm... i will recalculate exactly and very very detailed: AND if i find some extra costs on the Roadster, i will go back to the enviormental arguments and cut it from my children´s pocket-money - it their future, not mine. :biggrin:

 

[benji4]

If you add in a modest value for no emissions, HOV lane, coolest car ever, the Roadster wins hands down. Or in my case if you drive 15-20k mi per yr and your cost of capital is only 2.55%, (NPV of the gas becomes $132,000), and your power is almost free, the Roadster is a pretty sweet deal next to the other car!

Unfortunately I don't think gas will go up any faster than the general rate of inflation. That's a pretty lonely position around here. Even the GAO disagrees with me.

The more you drive the more you save on fuel of course, but how can you get nearly free electricity? By charging at the office, etc.? Even then somebody has to pay for it of course. I guess the closest thing to free power would be lots of solar panels on your roof but that's also not all that cheap. I agree with you that gas probably won't go up any faster than the general rate of inflation. They can't really because as gas prices increase demand drops, supply increases, people start conserving, new power sources are developed, and various other things which keep in check. Even at $4.00+ gas prices still pretty much in line with inflation long term. Kind of like housing prices... they can spike up now and then but reality always sets in at some point. People only have so much money to spend.

 

[VolkerP]

Residential solar might be a source of 'free' electricity. Feed in tariffs in Germany guarantee you a payback rate so you can pay off a loan for 100% installation cost within 10-14 years. After the loan is paid back, you have nice income for selling electricity. The feed in tariffs are guaranteed for 20 years. After the feed in tariffs run out, you could tear down the PV system or let it run and use the electricity inside your residential system for whatever you want. I don't know if you can use it to spind your meter backwards in that period, BTW.