From their web site:
In contrast, Powerwall’s lithium ion battery inherits Tesla’s proven automotive battery technology to power your home safely and economically.
I would be shocked if they weren’t the same 18650 cells they use for Tesla vehicles.
No direct cite, but I think so. Tesla has been planning this for a long time as a way to reuse their ESS battery packs before recycling them. This item from their blog in 2008 mentions it.
http://www.teslamotors.com/blog/mythbusters-part-3-recycling-our-non-toxic-battery-packs
I would bet that the PowerWall will come with a maintenance contract that insures Tesla of an ongoing solution to used batteries not quite ready for recycling.
Other than storing self-generated power, all it really can do is allow you to grab power during off-peak, so that you can use it during peak, or not use it and store it for an emergency.
If you’re like my uncle and live in a house that gets 12 feet of snow and loses connection to the grid for two weeks every year, the battery might be worth getting. (Though I think they enjoy roughing it for those two weeks.)
For everyone else, the goal would really be to save money.
The average electricity bill, per month in the US, is about $100. At $3000 per battery, you would need to generate 100% of your own power via solar energy (or other self-generated power source) for 2.5 years before you would be saving money. Of course, that’s assuming that you could get solar panels in sufficient quantity to actually power your home installed and operational for free. But, this being the real world, it’s more probable that you will need to purchase solar panels.
Based on some back-of-the-envelope math, based on the back-of-the-envelope figures here, it seems like the average house would need to generate ~6.5 kW per hour, and such a system would cost something in the $50,000 range. Adding that in, then, it would require 44 years before you would start to see a return on your investment. And I’m liable to believe that the battery will not last that long. You would need to replace it a few times during that time period, adding to the costs even further.
Alternately, you could ignore solar and just try to buy energy from the grid during off-peak hours.
Based on this, you can purchase off-peak for about 1/3rd the price as on-peak. Assuming that you used all of your power during on-peak, then you’d be saving $77 per month and in 3.25 years the battery would have paid itself off. However, I would expect that actual power usage is more spread out over the day and subsequently, you’d probably save only $50 or something so it would actually take 5 years.
Now, in a sense that does save the environment. By moving your consumption to off-peak, it helps to flatten the curve of daily energy use, and so you don’t need as many plants that specialize in handling fluctuations in power. If you just need a good, steady flow of power, instead of something irregular and spiky, then the number of options for the power plants become greater.
But for that to have much of an effect, almost everyone would need to flip over to having a big giant battery hanging on the wall of their living room. At that point, the price of off- versus on-peak will start to even out and your cost savings will diminish. Market forces will, over time, equalize at the point at which you’re basically going to break even whether you buy the battery or not. (Probably, it will mainly by big skyscrapers and apartment buildings which would see an advantage from buying and installing such a thing, while individual homes would suffer a loss from trying to buy one.) To be fair, that whole process would take 20-30 years, so you’re probably safe to not consider it at the moment.
So, for the moment, if you’re building or remodeling a house and you don’t mind having a massive battery built into one wall*, and you’re pretty confident that you’re going to still be living there in 6+ years, then yes, you’ll be able to save some money on your energy bills (after 10 years, you’ll have saved a whole $3000!) And you’ll have done a tiny amount of good in the world. But probably, this will make more sense as something for apartment buildings, and they’re going to do it more for the money than for the good it does to the world.
- I would be curious what happens to the battery if your house catches fire though. Fires could become a little bit more explosiony.
That article is pretty old. It cites installed solar costs of $7-$9, but median prices in 2013 were $4.7/W, and should be substantially lower yet today.
Of course this excludes tax breaks and other subsidies, which aren’t relevant when computing the environmental cost, but certainly make a difference to the individual consumer.
There’s also value in partial production. Many places have graduated rates–my top rate is something like $0.35/kW-h. I live in a sunny place, so a panel is likely to get about 2000 hours of good sun per year. So 1 W worth of panel will produce about $0.70 a year, and with $4.7/W installed costs will pay for itself in 7 years. But only for the upper portion of my usage–lower portions cost less.
This is obviously close to a best-case scenario, but the point is that the payback time is very dependent on the individual situation. Cheaper batteries widen the cross-section of consumers for which it’s a net win.
Another thing is that solar is very low-risk and zero-tax compared to other investments. If you’re wondering whether to invest in the stock market with an 8% return or in solar with (say) a 5% return, the latter is almost certainly better–you don’t get charged tax on saved money, and if your electrical usage is fairly constant, it’s virtually risk-free.
PS: It’s kW-hour, not kilowatt per hour. The latter is a very different thing and doesn’t make much sense in this context (don’t worry; it’s a common mistake and the article you cited makes it as well).
I know this is an older thread, but the Powerwall is finally available in my area and in the next couple months I will be installing solar panels and a Powerwall battery. I might buy two of them just because. The goal is to use zero electricity from the grid, and rely 100% on solar for electricity. The panels will charge the battery during the day and power daytime use, and the battery will supply power in the evenings. In CA we have net metering so if I generate more than I use I get credit for the extra generation. There is a $10/month minimum charge from my utility whether I use any or not. I’m pretty excited now.
I don’t think this is the right way to do the analysis. An ROI analysis is more informative than a break even analysis. Using your figures, if it’s $18K up front costs, for a $1,320/year savings, that’s really a 7.3% ROI each year. Not too bad at all. In my case, I think the figures work out closer to a 10% ROI which is pretty solid.
Cool–keep us posted.
In related news, Tesla is now producing cells at their Gigafactory. They had been doing some pack assembly already, but hadn’t been doing cell construction until now.
They’re switching to a new 21-70 form factor (from 18650), which is a bit taller and fatter, as well as having some other cost-saving measures in the design. It’s necessary for Tesla to hit their Model 3 price targets, and it looks like it’ll drive down Powerwall 2 costs as well.
We read the link. there’s no more to it. It’s a battery. And the link is over a year and half old. We’re as excited as we were with the I-phone 6.
You can buy a really nice natural gas generator for the price of the battery and actually go off the grid if the power fails.
In fairness, the OP’s post is over a year and a half old too.
I think you may be confused as to what “off the grid” means.
No I’m not confused. From Wiki: The term off-the-grid (OTG) can refer to living in a self-sufficient manner without reliance on one or more public utilities.
In this case the “grid” is the electrical grid. natural gas is generally immune to power interruptions unlike solar or wind systems which are spotty at best.
Good point. I missed that. They should color code anything over a month old. The op hasn’t posted since the first day of posting.
[tangent] If you don’t mind user scripts (Chrome or Firefox), here’s one that does that.
Natural gas is still a utility, so if you’re depending on it you’re not completely off the grid.
It’s a tad more reliable than the electrical grid but it’s still not 100%. In CA, there’s always the possibility of a large earthquake. Earthquakes can take out gas lines as easily as electrical lines.
Generators are a terrible solution for night time use as well. A battery serves both uses.
I don’t live in California and even there it’s far far more reliable than the electrical grid. The battery is more than the cost of a good generator and is completely useless by itself. It’s easy enough to install a multi-fuel generator for the cost of a Tesla battery which does NOTHING by itself.
So I truly don’t understand what your point is regarding an expensive battery that doesn’t produce electricity compared to a system that does for the same price.
For me, the primary motivator isn’t cost, though it is a consideration. I appreciate the ability to have power in case of emergency, and the ability to not be dependent on the Utility. That’s why I’m considering buying two batteries. If one is good, two is better! I’d put in more panels if I could but I’m not allowed to exceed 105% generation so that’s a bummer. The plan is to generate power in the day and use it at night from the battery, with enough in reserve to go a day or so with no power. I’m also not inclined to stock fuel for a generator to use on a nightly basis. An emergency generator would be a good add to the inventory.
Well, likewise I have no idea what you’re advocating.
The proposal here is a solar system with battery for night time and emergencies.
A typical emergency generator is only rated for ~2000 hours, so using it at night is a non-starter. Therefore you need the battery anyway. And if you’ve got that, emergency use is covered as well.
I guess you could get a genset rated for continuous use, but that’s going to be more expensive, and most people interested in solar power are trying to reduce their fossil fuel use. Plus they make noise and make you dependent on fuel.
What proposal? This is a zombie thread about the exciting new Tesla battery.
…bumped by Bone, who lives in California and is planning on installing a solar+battery setup. But if you want to wander off muttering to yourself, go ahead.
And what are you proposing? I posted prior to that regarding the cost benefits of a backup generator that matches just the cost of the battery.
when you actually propose something with cost figures make sure it works within your earthquake guidelines. I’ll leave you to it.
The Powerwall is largely intended to be used in combination with a solar setup, so that’s what I have in mind as well. It probably doesn’t make sense purely as an emergency supply unless a generator is impossible for some reason (like condo owners), or there’s some need for instant-on power (like if I were running some servers). But personally, I don’t see much value in having an emergency supply since power is so reliable. The power goes out less than once a year and then for only a couple of hours at worst.
The main purpose is to cover the nighttime gap in solar generation, and in this application it works well. A generator would be inappropriate in this application for the reasons cited. As a side benefit, going off-grid means you get emergency power for free.