cost per charge at home ??

[TexLaw]

I always get a kick out of this questions, since it's so rare to ask an ICE owner what it costs (or would cost) them for a full tank of gas. However, it's the first thing anyone asks me about my MS.

Anyhow, to keep things simple, I just multiply the 90kWh battery number by my flat rate juice, round, and tell them "I can go roughly 300 miles on about $6.50. That's a little better than 100 MPG at current gas prices."

 

[2012MS85]

My explanation in the past to a tee, but I've decided to change my approach because the majority of Americans cannot make the mental jump from pennies a mile to thousands of dollars a year. So I translate for them into dollars a month.

Very smart switch (to $$ per month). I guess that's why I always catch my wife rolling her eyes when I get too detailed with numbers around our friends, as she knows everyone has checked out when I fail the KISS approach!

 

[MorrisonHiker]

Instead of telling others a dollars per charge or dollars per month number, I keep it even simpler and say it's "about half to a third of the cost of what I used to pay for gas". The problem with saying it's $10 a charge and that you charge nightly might lead them to think that you are spending $300 a month. Then again, maybe you are spending $300 a month...but that sounds really high to me considering I used to only spend $60 a month for gas in my old ICE. I wouldn't use dollars per month either unless you're sure to specify how many miles you drive per month.

 

[SageBrush]

Anyhow, to keep things simple, I just multiply the 90kWh battery number by my flat rate juice, round, and tell them "I can go roughly 300 miles on about $6.50. "

I like this!

Something along the lines of "if my car had a 10 gallon gas tank, it would cost me about $5 to fill."

 

[Reciprocity]

Say you can generate 1.6 kWh a year from an installed watt
To match 9 cents a kWh from your utility, the installed cost* would be $3.65 a watt after the fed tax credit,
Or $5.21 before the tax credit

*25 year life at nameplate capacity, calculated from 0.5% annual degradation and nominal 30 year life.

This really sounds smart, but it goes over my head..haha. I will probably prey for hail or replace my roof in 10 years with solar tiles unless I live somewhere else and then it will depend on where and what state the roof is in. I love the idea of a 50 year slate roof though that can generate energy.

 

[SageBrush]

This really sounds smart, but it goes over my head..haha.

Not meant to go over your head ... the idea is simple so let me try and be clear(er)

You pay Y dollars for the PV array;
Over its lifetime it makes Z units of energy;
The Z units are worth Q dollars in averted utility costs

Then ONE unit costs you Y/Z;
And PV is likely cheaper than the utility if Q > Y

The rest is just re-arranging the terms and working backwards. I calculated one watt for convenience

 

[Reciprocity]

Not meant to go over your head ... the idea is simple so let me try and be clear(er)

You pay Y dollars for the PV array;
Over its lifetime it makes Z units of energy;
The Z units are worth Q dollars in averted utility costs

Then ONE unit costs you Y/Z;
And PV is likely cheaper than the utility if Q > Y

The rest is just re-arranging the terms and working backwards. I calculated one watt for convenience

BTW, thanks for your efforts. I am usually better at math.

My issue is not that it will or will not pay back the cost. I am sure it will pay back the costs. The problem is that I am impatient and there is a cost and it would tie up money for a long time while it is paying me back, so you have to figure in the lost opportunity costs.

The other issues that I have are the panels themselves are ugly, but the roof is stunning. My roof is only about half way through its life and I probably have 10+ years left on the roof. This is why I am preying for hail, because I would definitely consider the solar roof, especially if the insurance company and fed are going to pay for half the costs. It would be a no-brainer with 2 electric cars. The other issue is that I only charge at night and could only charge during the day on the weekends and the rates are so damn good. 9-10c per kWh as as little as -2c to -3c per kWh is rare cases. I don't live in CA so I don't have high electric bills in general, only about $125 a month with an Electric car, so it makes the payback time 13,15 or even 20 years for enough solar, 5-6kW to support my 1000-1300kWh per month needs. I guess I could go with a much smaller install, but I hate doing things halfway.

As an investor, I am very excited about the solar roof because it adds a new dynamic to solar that does not exist today. A major barrier is how ugly they are and how much expense it will add if you do need to replace your roof. With the potential of 5 million new roofs a year, most wont fit the criteria for a solar roof, but lets say a million a year do. That is a ridiculous amount of solar and Tesla wont just be making money from the solar component, but also the roof component. It would probably double the total gross profit from each install because it would encompass the entire roof. A 50 year roof that generates power is very compelling because it also ads to the value of the home vs a traditional asphalt or even wood shingle roof from purely a roof standpoint, much less the value of the solar. To me, like the electric car matching ICE in terms of cost/value, this is a game changer.

As a potential customer, my situation is a prime example, I have 10+ years left on my roof and I am paralyzed, but if a hail storm hit here, its almost a done deal. The only thing that would hold me back is an excessive cost or excessive delays.

 

[SageBrush]

The problem is that I am impatient and there is a cost and it would tie up money for a long time while it is paying me back, so you have to figure in the lost opportunity costs

The lost opportunity costs are mostly (or perhaps entirely) offset by avoiding utility inflation costs. PV is a fantastic low risk investment, and you do not pay taxes on your profits.

It pencils out really, really well for a large swath of the population.

As for PV on the roof being ugly -- I agree but that is not the money arithmetic I wanted to clarify. Have you seen the new SolarCity roof panels ? They are not tile pretty, but are low profile and much less off-putting to my eyes. Fwiw, I solved the aesthetic problem to my satisfaction by choosing a ground mount I built myself for cost savings and fun.

 

[Reciprocity]

As for PV on the roof being ugly -- I agree but that is not the money arithmetic I wanted to clarify. Have you seen the new SolarCity roof panels ? They are not tile pretty, but are low profile and much less off-putting to my eyes. Fwiw, I solved the aesthetic problem to my satisfaction by choosing a ground mount I built myself for cost savings and fun.

I do like the look of the new panels and frankly the look concern was more from an investor standpoint and not a personal one. As an investor I want to see innovations like the new panels and the solar that remove barriers to entry. Now what I am wondering is if they are cheaper to install and thus cheaper to remove and put back in 10 years when I will need to redo the roof.

I am kind pulling for global warming to hit my house with some baseball sized hail as it makes my decision easier.

 

[SageBrush]

Now what I am wondering is if they are cheaper to install and thus cheaper to remove and put back in 10 years when I will need to redo the roof.

The PV panels protect the roof, so I would not presume you have to remove them in 10 years. If I was considering the low profile panels I would be most interested in how they solved ventilation. A hot panel is an inefficient panel.

 

[oktane]

The price you are paying for the car far offsets any savings over the fuel cost. This is a false economy. Even if electricity is free, you do not save any money with a Tesla Model S/X over ICE. A car similar in build to a Tesla might cost $35,000. This is excluding matching performance, autopilot, cool factor, environmentalism etc.

This likely will not the be case with Model 3 if the car is truly $35k. That would be the real game-changer coupled with solar panels.

 

[Reciprocity]

The PV panels protect the roof, so I would not presume you have to remove them in 10 years. If I was considering the low profile panels I would be most interested in how they solved ventilation. A hot panel is an inefficient panel.

If you can roof around the panels then maybe. I was a roofer in college. If they are flush mounted to the actual wood underneath the shingles then you are correct. If they are not, it would be difficult to replace the damaged roof without removing the panels and putting them back after the roof has been replaced, but if they are more like a skylight and you can roof up to the edge of the panels with flashing around the panels, then you would be correct, the panels would not need to be removed. Could there be fans on the underside for ventilation? The heat would actually be useful in the winter but you would want to rout it back out through a roof vent in the summer.

 

[Xenoilphobe]

The price you are paying for the car far offsets any savings over the fuel cost. This is a false economy. Even if electricity is free, you do not save any money with a Tesla Model S/X over ICE. A car similar in build to a Tesla might cost $35,000. This is excluding matching performance, autopilot, cool factor, environmentalism etc.

This likely will not the be case with Model 3 if the car is truly $35k. That would be the real game-changer coupled with solar panels.

This is very true and in states with property tax your fuel savings is eaten up by the yearly property tax hit.

 

[SageBrush]

it would be difficult to replace the damaged roof without removing the panels and putting them back after the roof has been replaced

I presume that fixing or replacing a damaged roof would first require removal of the PV panels; I was saying that the expected life of the roof is likely extended by the panels above: no direct sunlight, no snow and probably no ice on them.

 

[Reciprocity]

The price you are paying for the car far offsets any savings over the fuel cost. This is a false economy. Even if electricity is free, you do not save any money with a Tesla Model S/X over ICE. A car similar in build to a Tesla might cost $35,000. This is excluding matching performance, autopilot, cool factor, environmentalism etc.

This likely will not the be case with Model 3 if the car is truly $35k. That would be the real game-changer coupled with solar panels.

This is very true and in states with property tax your fuel savings is eaten up by the yearly property tax hit.

Another things you have to factor in are the maintenance costs and the residual value. You are not competing direct with ICE vehicle based only on the fuel cost, but also the TCO or total cost of ownership.

This actually makes the $35k base model 3 more comparable to the base Camry then a 3-series BMW. I did an analysis somewhere else on the board but cannot find it, but it basically boils down to the total payments for each car. Lets assume 5 year loans for both cars. $580 payment for the model 3 and the $380 payment for the Camry. Over the 5 years the Model 3 could still be worth $20k because it has a million mile power train and has a ton of up-gradable tech like EAP and FSD. While the Camry would be worth only $12k. The original price difference of $12,000 has now dropped by $8000 to $4000 due to the higher residual value. After fuel cost savings, maintenance and maybe even insurance costs with all the built in driver assist software like AEB and lane departure and side collision warns and as we all know the EV drive train actually makes it considerably more safe. Fuel savings alone can save you $4,000 over 5 years, but if not, there's always maintenance. Oil changes, brake jobs, belts and whatever else. I know I have a lease on my wives van and its $750 for 3 years and covers only the bare minimum for the lease and that's discounted because we paid up front. That doesn't include breaks or 100,000 mile tuneups.

When you go to sell that Camry with 80,000 miles, it will need a new timing belt, brakes and a 100k tune up for the new owner. It will be at least 1/4 through its entire life. While the Model 3 will be under 10% through its life cycle based on the million mile power train.

One way to address the higher payment of $580 vs $380 would be a longer duration loan, with the idea that you can get out of the loan at year 5 if you choose to. So an 8 year loan to get the price down to where the Camry is with a 5 year loan. Sure the Camry will be paid off at the end of the loan, but the difference will only be the difference in residual value between the two cars. It would almost be like a lease, but leases will not have the right residual value from day one as they will need a few years to really establish the residual value.

 

[SageBrush]

This actually makes the $35k base model 3 more comparable to the base Camry then a 3-series BMW.

WAaay to complicated, and residual values on the Model 3 are a wild guess.

However ... 35k - 7.5k federal tax credit for the Model 3 is $27.5k. That is already Camry cost range before fuel savings are even considered.

 

[st50maint]

For the purposes of this discussion, if this were your bill, what number would you use for the cost per kWh?
$0.0819 (Power supply charges)?
$0.208 (total bill divided by 403 kWh)?
Something else?
View attachment 224704

 

[Reciprocity]

WAaay to complicated, and residual values on the Model 3 are a wild guess.

However ... 35k - 7.5k federal tax credit for the Model 3 is $27.5k. That is already Camry cost range before fuel savings are even considered.

I am basing my assumptions on the Model S, which is not a million mile power train. I wanted a model that did not include the tax credits, which will be gone by Dec. 2018 or sooner if they are eliminated by Trump or some new tax plan.

Also, my residual value argument isnt even nutty if you just factor in the fact that more expensive cars have a higher residual value then less expensive cars given the same overall quality. If the model 3 is trash, it will have a higher residual value still. If the model 3 is a very safe and reliable car after 5 years, it could have an even higher residual value due to the power train and upgrade-ability that does not exist with other cars in any class, aside from the S/X that is.

 

[oktane]

I am basing my assumptions on the Model S, which is not a million mile power train. I wanted a model that did not include the tax credits, which will be gone by Dec. 2018 or sooner if they are eliminated by Trump or some new tax plan.

Also, my residual value argument isnt even nutty if you just factor in the fact that more expensive cars have a higher residual value then less expensive cars given the same overall quality. If the model 3 is trash, it will have a higher residual value still. If the model 3 is a very safe and reliable car after 5 years, it could have an even higher residual value due to the power train and upgrade-ability that does not exist with other cars in any class, aside from the S/X that is.

Good analysis but there are too many variables to say for sure. Residual value on Tesla leases is not great, maybe 54% not including the boost from the $7500 federal tax credit. Also, insurance is ridiculously expensive on my Tesla compared to my other similarly priced luxury cars, by about a factor of 2x.

 

[Reciprocity]

For the purposes of this discussion, if this were your bill, what number would you use for the cost per kWh?
$0.0819 (Power supply charges)?
$0.208 (total bill divided by 403 kWh)?
Something else?
View attachment 224704

Here is an example of me charging my car from 1am to 6am. Comed lets me download usage data now that I have a smartmeter:
TYPE DATE START TIME END TIME USAGE UNITS COST NOTES
Electric usage 3/9/2017 0:00 0:29 5.01 kWh $0.53 $0.106
Electric usage 3/9/2017 0:30 0:59 5.01 kWh $0.53 $0.106
Electric usage 3/9/2017 1:00 1:29 5.02 kWh $0.53 $0.106
Electric usage 3/9/2017 1:30 1:59 5 kWh $0.53 $0.106
Electric usage 3/9/2017 2:00 2:29 4.99 kWh $0.53 $0.106
Electric usage 3/9/2017 2:30 2:59 5 kWh $0.53 $0.106
Electric usage 3/9/2017 3:00 3:29 4.96 kWh $0.53 $0.107
Electric usage 3/9/2017 3:30 3:59 4.96 kWh $0.53 $0.107
Electric usage 3/9/2017 4:00 4:29 4.95 kWh $0.53 $0.107
Electric usage 3/9/2017 4:30 4:59 4.98 kWh $0.53 $0.106
Electric usage 3/9/2017 5:00 5:29 5.1 kWh $0.54 $0.106
Electric usage 3/9/2017 5:30 5:59 3.32 kWh $0.35 $0.105
58.3kWh total $6.19 total $0.106 average

I am sorry, I misspoke early when I stated negative rates, that was only for the electricity. There is sill another 6 cents or so for delivery fees which I don't believe go negative though they might be discounted as well. So I would still be paying 3-4 cents a kWh even when the energy price goes negative 2-3c because I have to pay for delivery still. Either way, it is such a rare event that its almost not worth mentioning. I did select the time of day based on looking at data over the year to try to find the best time to have a possibility of lower rates.

So if I am reading this right, its about .042 cents for supply and another .04ish cents for delivery and a cent or so for taxes and fees. Roughly 10.65c per kWh.