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Tesla announces Powerwall, a home battery system starting at $3,000

By Scorpus ยท 17 replies
May 1, 2015
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  1. tesla powerwall battery pack in home battery

    One of the worst kept secrets in tech has been Tesla's in-home battery pack, details of which have leaked several times since early this year. But today, the company was finally ready to officially launch the battery system, which they're calling Powerwall.

    As part of a new product line called Tesla Energy, the Powerwall is a battery system that can be installed on the inside or outside of your home. It's designed to be paired with solar panels, charging during the day when solar energy is the highest but usage is relatively low, and then discharging during the night or morning.

    The Powerwall helps create a sustainable home, as it balances out the load on the power grid throughout the day, reducing consumption during peak periods, which in turn helps curb carbon emissions. It also can save a home owner money, as the Powerwall can charge during off-peak times at a lower cost, and then deliver off-grid power to your house during the more expensive peak periods.

    tesla powerwall battery pack in home battery

    On top of environmental and monetary benefits, the Powerwall can be used as a backup battery for when grid-based power goes down. This could be especially helpful in countries where power supply is unreliable, and where blackouts are frequent.

    The entry level Powerwall is a 7 kWh unit that will cost $3,000, but there's also a 10 kWh model available for $3,500 (plus installation costs). The units are around six inches thick, four feet tall, and three feet wide. All units will come with a 10 year warranty, and better yet, up to nine units can be stacked together to create a battery as large as 90 kWh.

    A business-grade battery called the Powerpack will also be available, which will start at 100 kWh and scale "infinitely" to power packs beyond a gigawatt-hour.

    The Powerwall will become available this summer in the United States, with Tesla's website allowing you to reserve a unit right now. The Powerpack will launch later this year, and Tesla will be focusing on business more in 2016. For those outside the USA, Tesla hopes to expand their battery pack business to Germany and Australia by the end of the year.

    Permalink to story.

  2. Skidmarksdeluxe

    Skidmarksdeluxe TS Evangelist Posts: 8,019   +2,894

    This will be very useful to me but sadly so will the money. If it comes to my country anytime soon and is subsidized by my electricity provider, I'm in.
  3. insect

    insect TS Evangelist Posts: 349   +131

    Elon Musk comes full circle...

    Solar City leases you the Solar Panels, Telsa Energy gets you the battery to manage that electricity, Telsa Cars sells you the car you can charge (also with your reserves from the solar). As long as the sun shines, you won't get a power bill or gas bill (assuming power consumption doesn't exceed battery capacity + solar) :)
    cmbjive, SirChocula and 9Nails like this.
  4. wiyosaya

    wiyosaya TS Evangelist Posts: 1,533   +516

    Well, I hate to poo poo this, but 7-kWh or even 10-kWh is not much of a battery backup. Anyone who jumps in on this without analyzing their own power usage might just be highly disappointed that in a power failure, the battery will last only as long as their home power usage allows.

    Say your refrigerator (something I think most people would want to run in a power failure) consumes 300W. Divide 300W into 7kWh and you get about 23h. So, your refrigerator, and only your refrigerator, will be able to run for about 23-hours (assuming that your refrigerator does consume only 300W and BTW, I am not sure what the power draw for fridges is these days, but 300W used to be achievable only by the most expensive and most energy efficient models). The more power draw you add on, the less time you will have. Forget running anything like an electric dryer or any other electric device that consumes large amounts of power like a hair dryer, microwave, etc., for any length of time.

    Tesla is trying to make it easy for people to get off-grid and I commend him for that, but I think without assistance to the customer in determining their electrical energy needs, I think Tesla and Musk are quite possibly in for a nightmare when some energy hog house cannot run for more than an hour or two on this system in a power failure.

    Anyone, IMHO, seriously considering getting one of these for serious off-grid or even backup power would do well to get the book "Wind Power" by Paul Gipe as it extensively explains how to figure out your energy needs and size a system accordingly with both wind and solar power. http://www.amazon.com/Wind-Power-Re...30490753&sr=8-1&keywords=paul+gipe+wind+power
  5. MilwaukeeMike

    MilwaukeeMike TS Evangelist Posts: 2,840   +1,184

    Kinda reminds me Google that way. They're rolling out Fiber and a cell network that you can connect to on your Google phone and use Google apps and Google search.

    yeah, like in the middle of the desert. I bet people who like living in the middle of nowhere will jump on this.

    I think this is a big step toward the progression of solar power. The two big issues with solar are high cost of panels and the sun hiding behind the earth half the time. This battery solves one of those problems. Hopefully in years to come this solution will be used widely enough to take a little pressure off the grid, which is old and stressed already. I know Solar City will allow you to lease solar panels, but until the cost comes way down or they become far more efficient, solar panels will still just be ways for rich people (and businesses) to feel like they're making a difference.
    Tesla needs to come up with a better battery technology and they need to put them in gadgets if they want to revolutionize the battery industry.
  6. Camikazi

    Camikazi TS Evangelist Posts: 896   +264

    While you are right you are assuming this will be alone when it is designed to be used with solar panels (which I am guessing most will do) making it much more useful than you make it seem. Combining this with a comparable solar panel kit can pretty easily keep you off the electrical company grid completely and even during a blackout can keep you running since it would charge up during the day, as long as you don't run everything at full. This thing alone can run my entire place for around 11 hours (I average around 16 kWh a day). As for the fridge thing mine is a bit old and wasn't expensive and uses 228 watts, fridges aren't such a huge electrical user now. Also even a 1500W hair dryer would have to be run for almost 5 hours to drain then 7 kWh battery, this is really a very useful thing and if you can get is subsidized or maybe as a combo with a solar panel kit would be a perfect way to lower energy bills (assuming the monthly payments are low enough).
    cliffordcooley likes this.
  7. Can't wait for the future when instead of grass,every house will have a lawn and roof of just solar panels.
    Last edited by a moderator: May 1, 2015
    SirChocula likes this.
  8. davislane1

    davislane1 Inquisitor Posts: 4,509   +3,510

    Perhaps in California, where it doesn't rain anymore.
  9. wiyosaya

    wiyosaya TS Evangelist Posts: 1,533   +516

    It sounds like you did your research, however, I am not assuming it would be alone.

    The book I mentioned is quite concise in its descriptions of what is necessary and how things work together. About 15-years ago, I considered an off-grid solution for a remote location I considered purchasing. At that time, and most likely at this time, too, an ideal solution would have consisted of both solar and wind with battery backup since neither solar nor wind deliver consistent power. Under ideal conditions, the solar solution and the wind solution would be large enough to supply all the electrical needs of a home with no dependencies on the other sources since one or the other may not always be available.

    As I see it, though, it is unwise to consider a singular source of energy drain in the equation to size the solution to the energy needs of any home. That is specifically why I gave a simple example yet qualified that example by saying
    Most homes under normal circumstances are likely to have several items drawing power at the same time.

    As I see it, even with the energy efficiency advancements that have been made in the 15-years since I considered such a solution, the informed consumer will assess the energy needs of their home before running out and buying anything. It sounds like you fall into the informed user category.

    The simplest means of doing so would be to average a home's electrical usage from the monthly electrical bill. My current house (which has some of the latest energy efficiency gadgets like CFLs and LEDs) uses 800 kWh / month or approximately 26 kWh / day. This includes an electric dryer that itself consumes 5kW. On an averaged basis, Tesla's 7 kWh pack would last me about 6.5 hours. Performing these calculations on an averaged basis is, IMHO, the safest route to take.

    The more complicated approach is to figure out the power draw of each device in a home and add these all up.

    Also, one needs to figure the average amount of solar power per day that one can expect for one's location. For me, it is 3-hours / day. This is then used to size the solar array to the needs of the home, I.e, does one need a 1 kW array, a 5 kW array, etc...

    If wind is added, one needs to figure the average amount of wind power available at one's location and size the turbine to the needs of the home remembering that each source, I.e., wind or solar, must be able to power the home in the absence of the others. Where wind is concerned, most small (I.e., less than 10 kW) turbines will shut down in high winds, so I recommend finding one that does not - they exist and they used to be manufactured by a UK company called "Proven" but they have change hands and names at this point.

    It would also be interesting to know under what conditions is the Tesla pack rated at 7 kWh. Usually, batteries are rated under ideal conditions, yet in practice, ideal conditions are rarely achieved. That rating will degrade with each recharge cycle for instance.

    My point is that entering into this with high expectations with out counting all of one's eggs before hand will likely lead to disappointment, and most people who fail to take this seriously and educate themselves about their energy usage and then buy this pack are the people most likely then to say that Tesla's pack does not work and blame Tesla for it rather than their own lack of research (at least as I see it anyway).

    An off-grid home is no trivial matter, anyone, IMHO, who assumes it is is likely in for a big disappointment.

    So if you are serious about it, get that book. It is probably the best on the market in my opinion. Spending the $40 on it now is well worth it as it will lead all who are serious about being off-grid to a solution that will work in even the worst of times.
    Darth Shiv likes this.
  10. DaveBG

    DaveBG TS Addict Posts: 272   +87

    I will be getting one for sure.
  11. Camikazi

    Camikazi TS Evangelist Posts: 896   +264

    I have done some looking up and I know it is very hard to get off-grid but I don't think this is made for that, it is more a cost cutting option that along with other options can lower your monthly usage. Most solar panels systems and even wind energy systems can't actually power a house 100%, they are just there to help curb the sometimes crazy peak energy costs and this just helps when combined with those systems. I will definitely be looking into this if it can be subsidized since prices for electricity here can be odd and have been going only higher each year.
  12. Darth Shiv

    Darth Shiv TS Evangelist Posts: 1,767   +435

    You won't need a subsidy soon. The cost of this tech has plummeted and it has not reached economies of scale. It is around $250/kWh for batteries now. 4 years ago it was $1000/kWh. In a few years it will drop under $100 and I'd say further than that.

    Instead you'll get finance. At the current prices, even without net metering (where you get money for energy you supply back to the grid at the rate you would have to pay for it), the payback period is < 4 years. After that you are making fat profit. If anyone is interested in more specific details, there are published academic papers on this matter directly. One I know of used $300/kWh pricing so you are going to make more money now than what the paper calculated.

    The key is scheduling when to use the stored energy vs using grid energy. Basically use the battery when the grid is charging the highest price and use the grid when it is off peak pricing. That's one good strategy. I imagine there are other good strats too.
  13. Darth Shiv

    Darth Shiv TS Evangelist Posts: 1,767   +435

    It is easy to get off grid if you have enough $$$. When I ask the question: "what about off grid?" to utility grid planners I get back are the following:

    Reliability of supply. If you rely on solar, you need a LOT of storage to protect you for the cloudy days. An average house in Australia uses approximately 20kWh per day all year round. So this Tesla battery will only supply you for 12 hours on an average day let alone a high demand day like a stinking hot day or freezing cold day where you are using your air con or heaters. Probably ~40kWh

    Also if you have that much storage, how are you charging it? An average roof of panels is only 3-6kW. That is in perfect conditions. If you have a cloudy day, you won't be charging the batteries much at all. Imagine a week of poor conditions? You will need a generator to help you get through.

    Ok so assume you have a diesel generator. Did you know for reliable operation, they need to be run daily? Yes that's right. If you want your generator to work when you need it, you need to supply it with fuel and run it on a daily basis. Even though you don't need the diesel at all for 350-360 days a year. That's all so the few days a year when your batteries don't help you enough, you want to top up supply. It's a very expensive operation for a single household.

    Maybe you could just sweat it out or use lots of blankets instead? Candles? Throw out the food from the fridge when your power dies?

    That's why being grid connected (maybe a micro grid?) is economic for reliable household level supply.
    Last edited: May 1, 2015
  14. dob_1

    dob_1 TS Member Posts: 23   +7

    With Solar Panels one of the biggest problems is that just as the sun stops shining (on a day without clouds/rain I mean), the time of use power rate goes sky high. 38c / kWh for us. All day we are getting 6.2c for generation, then when that stops the cost skyrockets. It stays that way until 11pm, so a battery back that could last through to 11pm when 11c /kWh power kicks in will save heaps on energy costs.

    The programming has to be good though. No use having a full battery charged over night, then only using 2 kWh or so during the morning before the sun kicks in during the day allowing the panels to produce excess. Must be able to program it to charge up to a certain percentage overnight on offpeak rates and then be nearly empty when the sun comes back during the day (assuming not too much cloud of course.)
  15. Skidmarksdeluxe

    Skidmarksdeluxe TS Evangelist Posts: 8,019   +2,894

    That may work where you are but I'm in South Africa. Anybody who installs a solar geyser here can apply for a subsidy so I hope the same thing happens when this tech finally comes to my country.
  16. Belty

    Belty TS Rookie

    We live in a semi remote area in Oz and lose power at odd times. Have 7.5 kw on the roof plus a 7.5 kw generator.

    One of the big issues swapping thru the on/off line options is the power company wont allow you to switch to your solar system during a power fail. Why? At the moment they can't isolate you from the grid and obviously don't want solar power to zap their repairmen. Appreciate that's procedural but a pain when you have been down for 3 days and getting zero input from your panels.

    However I see the Tesla initiative as being battery half full and a useful step along the way to more practical, cost effective and greener solutions in due course.
  17. And I don't understand why you complaining that 7 kWh Tesla battery isn't enough, if it doesn't enough, you can buy more than one then install it together as the Tesla suggest from it's site.. end of problem
  18. dob_1

    dob_1 TS Member Posts: 23   +7

    We were told the reason the power companies won't let us use Solar during a blackout is because the generation fluctuates so much that if you are using motors etc in the house and the sun goes behind a cloud you could burn out your motors and damage the whole household system with under voltage - A battery would prevent this, but it would still only cover a few hours blackout.

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