Power price comparison.

Power price comparison.

In Australia we have a power connection fee, so you will always have that. But if you used a Power Wall to store power for off peak periods and used the battery for peak....
In Australia peak power is over 7 times more expensive than off-peak. I would be interested in seeing a cost breakdown.

McLary | 2016年11月4日

The basic cost for the PW2 during it's lifespan will be about $.20 per kWh in USF. That calculation assumes that it will run down to about 60% capacity over a 10 year life. Your cost would go down if you are able to extend the life beyond 10 years. This price is for the PW2 only. No cost of solar or grid power is included.

levan.pavlenishvili | 2016年11月4日

Does anyone know about prices of new solar roof? Can anyone provide any price estimates for that product?

dsvick | 2016年11月4日

@levan - Pricing will vary widely depending on where you are located, local incentives, number of installers in your area, the number of panels you need, the type of panels, other electrical work you would need done, and many other factors. You would need to contact installers in your area and get estimates. | 2016年11月4日

@levan - Actual pricing is not available yet. The solar roof is not available today and is expected in the Summer of 2017. Even then, there are a lot of variables as dsvick points out that will require an analysis of your specific needs.

johndoeeyed | 2016年11月4日

Your numbers are BS as I have explained on this forum elsewhere.
It seems you do not even know the specs of the Powerwall2.

McLary | 2016年11月5日


Lets see your math


johndoeeyed | 2016年11月5日

Email me privately at, propose a bet that I cannot, and then I will bother.
As you can tell, I am a bit tired of explaining and proving things to ignorant and lazy people, for free.

shaw_way | 2016年11月5日

I normally don't respond to Trolls and you are only half right. I can only go on the specs and price of the Powerwall as posted on the Tesla site for Australia (They are uo). I can also only go on the prices based on my usage and costs. I wanted to see how others stacked up.
As to my math:
Costs $$200AU per month = 2400 per year.
As to the 7 times cheaper, you can look up any provider in Australias web sites
and check out the prices (It was actually over, but I rounded down).
Buying power off peak brings my cost to 343, so call it $350
So I save around $2000AU a year.

Where you are right is the degradation in capacity over time. The only information I found on this was a site claiming to have a copy of the Tesla warranty. No one can claim to have accurate figures as they haven't been around that long.

johndoeeyed | 2016年11月5日

The Powerwall2 is warranted for 10 years for unlimited cycles.

EaglesPDX | 2016年11月6日

@shaw-way " I would be interested in seeing a cost breakdown."

The 10kWh Powerwall is $5,500. What would you save each day charging the Powerwall(s) at night on cheap power and not using utility power during the day. | 2016年11月6日

Powerwall 2 is 14 kW for $5,500 + $1000 (or more) for installation. The 10 kW model is no longer available (not sure if it was ever made either).

grega | 2016年11月6日

The installed Aussie Powerwall is just over A$10k.

Energy Australia is A55c/kWh peak, A12c/kWh off-peak. So the potential is 13.4kWh to transfer at a 43c difference, or $5.75 a day savings.

The first problem comes when you start to calculate everything out. You need to do weekends differently as they don't have peak (shoulder is 22c/kWh so saves 10c x 13 instead).

$136.57/mth savings.
At first glance.

So put $10k into a loan calculator with 10 year pay off and it's an easy saving.

* that 13kWh will decline over 10 years
* there are maintenance costs
* peak/off peak prices will change
* you may want to keep 4kWh in reserve for power failures
* other stuff I've not thought about or forgotten.

More importantly if you only use 8kWh in peak then that's all you can save big on. And your powerwall has to be smart enough to activate before peak starts so you can make the 10c on shoulder too, without running out before your peak rate ends.

All up - worthwhile if you use more than 10kWh in peak I'd say.

And better if you also have solar.

johndoeeyed | 2016年11月6日

I believe there are no maintenance costs.
It can be cycled more than once a day.

grega | 2016年11月6日

Yes the other factor is solar.

If your panels can give you 13kWh in the day then you can charge your powerwall off peak to get you through to 2pm, and the solar will offset that and give you the 13kWh needed for peak.

That'll save an extra 10c/kWh for whatever you use during morning shoulder, plus it'll be A49c x 13 kWh saved during peak (55c-6c sell-back rate).

Of course intelligent control of charging levels would maximise that.

McLary | 2016年11月7日

"The Powerwall2 is warranted for 10 years for unlimited cycles."

True, however, not worth the paper it is written on, since the warranty DOES NOT cover normal degradation and loss of capacity from normal usage. Tesla defines those terms, though the law in some countries could allow some recovery. Face value makes the warranty worthless to an average consumer.

All cost comparisons must take into account ALL of the following;
Total cost of installation with permitting. I estimate $7500 USF. $10000 ASF has been quoted elsewhere
Degradation and actual useful life expectancy. Declining scale of usable storage capacity. I estimate 65% @ 10 years.
Efficeincy. Losses and practical depth of discharge during use. 100% DOD claims are false and not practical. 92% efficiency is also not proven. DOD does not affect the useful lifespan calculations, but does restrict the daily power available for consumer use. DOD will affect the maximum cycled power available.

"The Powerwall costs $5500.00. That is 10.7 cents per kwh" This estimate is far too generous to start, with full daily cycling of 14kWh daily for 10 full years. But I will let that 100% blue sky stay as a starting point.

Actual Powerwall cost is $5500+$1000+$1000 = $7500. You must include Tesla installers and permitting costs. None of us can say with certainty what the total is, but my estimate is certainly not unreasonable.
That makes the cost now $.1459 per kWh.
Round trip efficiency is claimed to be 92%. This will impact usable electricity. Add 5% =$.1532 per kWh.
There is no free pass on lost capacity here in the real world. In practical terms the cost will increase by about 1/3. = $.2043 kWh Using a midpoint cost of degradation will yield a total cost of $.18 per kWh, lifetime.
New total = $.20 per kWh. This does not take into account the cost of solar nor the cost of grid supplied power. Your mileage will vary, but this is not an insane cost projection.

It may be possible that the PW2 will have a useful lifespan beyond 10 years. If that is the case, then the projected average price per kWh would be reduced.

Conclusion; Any power arbitrage would need spreads greater than $.20 per kWh to begin to make any economic sense.

McLary | 2016年11月7日

"It can be cycled more than once a day."

Not on Earth. Maybe Mars.

McLary | 2016年11月7日

I also failed to include at least one inverter replacement @ $2000. That's worth another $.04 over the lifespan.

Silver2K | 2016年11月7日

Powerwall only makes sense (at this time) if you live somewhere electric lines don't exist (imo)

johndoeeyed | 2016年11月7日

You do not know what the warranty covers.
You do not know what the 'lifetime' is.
You do not have any reason to doubt the efficiency.
You simply make stuff up to suit.

Red Sage ca us | 2016年11月7日

That does it. G'bye fake McLary.

McLary | 2016年11月8日

Please feel free to dispute anything I posted. Pricing and warranty terms are public information. The only open question is the potential lifespan beyond the 10 year warranty period. It is not a safe bet to assume there will be any useful life beyond 10 years. The rest is math that even an idiot can comprehend.

johndoeeyed | 2016年11月8日

I have already disputed several things you have posted.
Your latest 'It is not a safe bet to assume there will be any useful life beyond 10 years' is yet more made up bunkum.

McLary | 2016年11月8日

You can dispute whatever you choose, idiot. If you have any facts, figures, or something actually worth reading, please feel free to post them. Otherwise go be a gnat on someone else's ass.

johndoeeyed | 2016年11月8日

grega gave figures for his situation.
You simply choose to ignore them because it suits you to do so.

McLary | 2016年11月8日

So you cannot dispute my figures with anything but your normal bleeting.

johndoeeyed | 2016年11月9日

Please bother to read grega's figures, and you will find that they disagree with your opinion.
I have disputed several of your statements on this thread, but you simply ignore it.

McLary | 2016年11月9日

Listen idiot. Grega's numbers do not compete with mine. They give his example of costs and potential savings in Australia. One of only a few places in the world where the PW2 can make economic sense.

Take his maximum arbitrage figure of $.43 per kWh and $5.75 per day savings. Now deduct the actual cost of $.26 to operate the PW@ leaving $.17 per kwh or $2.28 per day actually saved.
$2.28 x 22 days per month is $50.12 maximum savings. No point in cycling power on weekends as it would lose $.04 per kWh, and simply degrade the batteries further.

So in one of the best places in the world to use arbitrage for power savings you could actually save $50.12 per month in Ausralian Dollars. I'm sure a case could be made in 2 or 3 US states as well.

Adding solar doesn't help the economics, as net metering is far more valuable than the storage added. Charging a car from solar plus battery will require several units.

johndoeeyed | 2016年11月9日

You are making things up to suit again.
Since you accepted $5.75 per day, you can see that a $10,000 installed cost is paid off in less than 5 years. Of course this is a non-definitive number, but it shows that a Powerwall makes sense to many people.
There are many parts of the world where a Powerwall makes sense, and Tesla will sell every one they can make.

McLary | 2016年11月9日

I've made nothing up. In simple terms, (the only way some can understand) in the US you will require an arbitrage spread greater than $.20 to even bother with the PW2. That becomes $.26 in AUS currency.

BTW the $5.75 works out to break even in 6.6 years, assuming the spreads stay high the entire time. Weekends don't count, unless the goal is simply to waste battery cycles.

There are parts of the world where this can make sense today. Tomorrow, as more backup storage and grid leveling become the norm, arbitrage spreads will narrow. Successfully implementing grid level storage will kill arbitrage opportunity for individuals. Just as net metering profits are being clawed back from customers, so too will opportunities for TOU arbitrage.

But it doesn't matter to the 1%. Spending $5k, $10k, $20k, or whatever on batteries to appear "green".

grega | 2016年11月10日

I'm trying to understand your maths McLary, would appreciate your help.

The 92% round trip obviously affects efficiency.
I understand the $.1459 per kWh used (assuming 14kWh cycled every day for 10 years). And can add some extra costs which I'd need to add in mine similarly.

At 20c/kWh what you're really saying is each day it costs $2.80 to have a powerwall. (14kWh, 10years).

So if you're not saving that much on energy it's running at a loss.

By saying it's a daily cost, I try to recoup that even on weekends. By saying it's a kWh cost, you wouldn't use it on weekends.

Can you "save up" those kWh, extend the life? Can you truly equate 5 days a week for 14 years (after which it's dead) with 7 days a week for 10 years.

I don't think not using it will save much money. It's made to be used. The powerwall will last longer than 10 years. But to simplify calculations we say 10 years... and use it well.

If you calculate how much a car costs per mile, it's expensive. There are lots of overheads to include. If you realise it costs a lot, you take it out less, but the cost per mile goes up because the fixed overheads are still there.

Same with a 10 year payout you're using on powerwall. Using it often (twice daily) will increase the value proposition not decrease it. (Yes I'm assuming he powerwall doesn't die after 4 years of heavy use!)

johndoeeyed | 2016年11月10日

The Powerwall2 is warranted for 10 years of unlimited cycling.

johndoeeyed | 2016年11月10日
McLary | 2016年11月11日

Nice story. A bit light on actual facts such as how many powerwalls? There is zero chance that it can only be one, as that is not enough storage to run a home, let alone ever charge a car. But don't let the facts get in the way of a good fairy tale.

@grega, the point about the weekends is that it would simply be foolish to lose $$$ on every kWh that you cycle on the weekends. The financial comparisons were for TOU shifting.

McLary | 2016年11月11日

@grega Please explain how you can cycle the powerwall twice a day? You charge it with cheap power at night and sell that back during peak times.

"The Powerwall2 is warranted for 10 years of unlimited cycling." The warranty DOES NOT include degradation or loss of capacity from normal usage.

grega | 2016年11月11日

@McLary no problem. It's usually just for people with Solar.

Lets say you use about 9kWh shoulder (7-2pm) and 12kWh peak (2-8pm), and another couple in the final 2 hour shoulder. Lets also say you get about 16kWh from your solar panels.

So you charge your PowerWall to 7kWh of off-peak in the early morning. That power is slowly used in the day, replenished with 16kWh of solar during the middle of the day. Total 23kWh.

johndoeeyed | 2016年11月11日

As usual you keep making stuff up to suit, so much so that you deny an actual owner's figures in preference to your own.
As you have been told before, you have no idea what the 'degradation or loss of capacity' is. It may be 5% for all you know, and you do not.

grega | 2016年11月11日

@McLary, obviously the cost of the powerwall can be calculated as $10k or so including inverter replacement at 5 years or whatever as you've done. But that's not actually a per kWh charge.

Part of the cost is related to cycling, but there are also fixed charges that it'll cost you whether you use it or not. So just as a car costs some people $1/mile to run once you factor in the fixed costs and divide by the miles, the incremental cost per mile is much smaller (gas and servicing).

You've taken the price, fixes, 10 year warranty, and maximum 14kWh, and worked out the maximum number of kWh that can get cycled through it in that time - costing 20c/kWh. NOT using some of those kWh doesn't save you 20c/kWh though... it's still the same 10 year cost. All the 20c/kWh cost does is allow you to work out the average you need to get back... so if half your kWhs were 30c and half were 10c that would average out, but if half were 30 and you didn't use the other half, the average of 30 and 0 is 15c... so a loss.

grega | 2016年11月11日

BTW I'm not an owner (if you're referring to me @johndoeeyed), but I've been working with my brother using the actual costs to calculate what will work. McLary is making me think of it differently... mostly asking "why is this inconsistent with my calculation... what is being missed... and is it me or McClary".

The interesting thing is how many assumptions don't hold as well as you expect. But still our current rates here in NSW Australia are so high peak that it'll work..

It also works much better for higher-energy houses. If you used 50kWh/day with a 5kW solar system, a 14kWh powerwall does a good job - because you can be off grid from 7am to about 9pm. More in Summer, less in Winter of course. In summer you'd partly charge off peak for your morning, and use Solar for the rest, in Winter you fully charge off-peak, but need to use some of the early shoulder-rate grid power so that you avoid any peak power charges.

A smart inverter for power management would be a game changer, like Reposit has. I wonder how Reposit's power management will work with Powerwall 2.

I suspect west facing solar panels will take on a new life now too.

McLary | 2016年11月12日

Your mileage will vary of course. I am simply trying to show the very real, basic cost of ownership of the PW. If you do not use the total available capacity, and the unit needs replacing after 10 years, then the cost per kWh will be increased accordingly. I have NOT included an inverter replacement. That could easily add 20% to the calculated costs, if needed.

Doehead keeps implying I am making things up. He is incapable of actually disputing my very simple math. Could I be wrong? Of course. I guarantee that actual numbers will not be exactly as I show. Anyone who has read the previous versions of the PW warranty will realize that Tesla DOES NOT believe that the PW will have an extended lifetime, beyond the warranty period. Also the warranty, as written, will provide little or no recovery to the buyer, for any normal loss of capacity. In plain English, the warranty cannot be relied upon, should capacity become seriously degraded.

grega, good luck with your project. Do mind the real risk that TOU spreads will almost certainly be reduced in the future. Also note that it will take multiple PW units if you intend to charge a car using your own solar power.

johndoeeyed | 2016年11月12日

You do make things up. Why should should the Powerwall2 need replacing at 10 years when it it warranted for 10 years for unlimited cycles? If it 'needs replacing' before 10 years it is replaced for free. If it lasted 10.0 years, then there is no reason it should need replacing at 10.1 years.

You keep assuming that the Powerwall will only cycle once a day. That is false.

You assume that the cost of islanding your house for power cuts has a customer value of $0.

Once again, you have no idea what the warranty is. You have absolutely no basis for saying 'the warranty cannot be relied upon, should capacity become seriously degraded.'. You simply made it up, but go ahead and prove me wrong. You will not of course.

McLary | 2016年11月13日

"In addition, this Limited Warranty does not cover (a) normal degradation of your Powerwall’s
energy capacity over time; (b) normal wear and tear or deterioration, or superficial defects,
dents or marks that do not impact the performance of your Powerwall; (c) noise or vibration that
is not excessive or uncharacteristic and does not impact your Powerwall’s performance; (d)
damage or deterioration that occurs after the expiration or voiding of the warranty period; or (e)
theft of your Powerwall or any of its components."

Seems quite clear to me. I don't care how many times it is cycled. Tesla clearly has the option to refuse warranty service, unless you can prove degradation was not within normal parameters. Tesla decides what those parameters are.

Having read previous versions of the warranty, with specific degradation schedules, it is absolutely certain that Tesla knows how much degradation is expected. However, they do not disclose that information. Everything now falls under the blanket of "does not cover (a) normal degradation of your Powerwall’s
energy capacity over time". Read those words a few times. The warranty is less valuable than the previous one which expected 40% degradation in the second 5 years.

"If it 'needs replacing' before 10 years it is replaced for free" Now who is making things up?

Your blind belief in everything Tesla is fine as long as you do not mislead others. The PW warranty is not worth the paper it is written on, as there is no guarantee of any recovery, in the event of degradation from use.

You try to imply that the existence of a 10 year warranty, somehow guarantees that the lifespan of the product will therefore far exceed the warranty period.

Enter bleeting sheep..........

grega | 2016年11月13日

@McLary, if you're going to assume the unit deteriorates due to use, then if you don't use as many kWh regularly then the deterioration will be less over time (same deterioration per kWh used). In reality, it'll end up being a combination of use and time. You can also be sure that Tesla will have an expected deterioration of the battery - that's the very reason they write into the warranty that the expected deterioration is not covered.. so your guess that it'll lose 1/3 in 10 years may be quite incorrect, we don't know, but I would expect a definition of deterioration. Given that the car batteries are performing better than expected it may turn out quite good.

I agree the Time Of Use difference will reduce in the future. How much it decreases will depend on how cheap batteries get - eventually the economies of scale should mean that a bulk battery peaker system shared between 300 houses will cost less per stored kWh than what you can buy at home, so ultimately that's against us.

What we've got in all our favour though is the slow speed that the industry reacts at. There's certainly quite a few years where they'll be catching up. There may also be realestate issues, it takes space to setup an energy storage facility.

Solar and batteries will increase their synergy too as long as the energy companies continue to buy-back solar excess at a low price. But I took a look at the spot prices in Australia yesterday and Tasmania spent most of the day paying people to take energy - too much solar and good recent rainfall I guess, plus lower use on a weekend. I expect that solar excess at noon will pay very little ongoing.

johndoeeyed | 2016年11月13日

You do not know what normal degradation is. That is the pertinent point. For the Tesla car battery it is 20% and people are experiencing only 10%. If the Powerwall2 has a similar degradation then you arguments about it needing to be replaced are incorrect.
Furthermore, you do not know if Tesla is producing 2170 batteries in small quantities at the gigafactory, or not. I expect that they are, and these are going into the new Powerwall and Powerpack.

McLary | 2016年11月15日

You can suspect whatever you wish. If there were any cell production in Nevada, it would be shouted from the rooftops.

Car battery longevity has nothing to do with storage batteries. Totally different chemistries and applications.

Read previous PW warranties for understanding. Do not try to cheerlead based on wishful thinking.

johndoeeyed | 2016年11月15日

You have no idea if cells are being produced in Nevada already.
You have no idea what the Powerwall2 battery longevity is.
You have no idea what the Powerwall2 degradation longevity is.
In summary, you have no idea what you are talking about.