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Tesla Announces Home Battery System

An anonymous reader writes: Early this morning, Elon Musk finally revealed Tesla's plans for the home: battery systems designed to store up to 10 kWh of power. The company is leveraging the battery technology they've developed for their electric cars to enable more people to switch to renewable power for their homes. There will be two models of the battery. The 10 kWh version will cost $3,500, and the 7 kWh version will cost $3,000. They can deliver power at a continuous rate of 2kW, with peaks up to 3 kW. Crucially, the batteries will be warrantied for 10 years. Musk thinks the market for home batteries will expand to at least two billion, eventually. But even a much smaller uptake for now will validate the creation of Tesla's "gigafactory."

"The gigafactory is the recipient of the largest incentive package ever given by Nevada at $1.3 billion, which followed a hotly contested tax incentive bidding war between various states to land the Tesla battery plant. For the investment to pay off, Tesla needs to convince hundreds of thousands of consumers per year to buy its cars and battery products, with the gigafactory serving as a cornerstone to the company's sales strategy. ... An early gigafactory rendering released by Tesla stated that the plant will have an annual battery pack output of 50 gigawatt hours — the bulk of which will go toward batteries for cars with most of the remainder to be allocated for stationary batteries, according to figures mentioned by Tesla's chief technology JB Straubel last year. The gigafactory's sheer scope makes other battery products a possibility as well."

15 of 514 comments (clear)

  1. Gamechanger by vakuona · · Score: 5, Insightful

    This battery could power a smaller sized home for a whole day. Kind of thing that can make solar energy viable.

    Love him or loather him, but Musk is changing the world.

    1. Re:Gamechanger by hodet · · Score: 5, Interesting

      I priced out a backup propane generator as a backup for my home that cost about the same thing. Never went with it. This could provide a home with good backup power in case of outage. (keep the sump pump or the furnace going anyway)

    2. Re:Gamechanger by ShanghaiBill · · Score: 5, Interesting

      Panel efficiency falls by half during cloudy weather, but you will still get some power.

      You get less power on cloudy days, but you also need less, since AC is the biggest consumer of residential power.

      Just means you pull more from the grid during winter.

      Which is not that much of a problem. Winter power consumption is spread out more than summer consumption, so the grid can deal with it more easily.

      The biggest challenge is the 5-7pm peak in demand. Just as solar is dropping off, people come home from work, kick on the AC to cool the house down, and turn on the appliances to start dinner. If these batteries can help shave off that peak, that will be a big help.

    3. Re:Gamechanger by Anonymous Coward · · Score: 5, Funny

      It's a mixture between loathe and lather.

      You'll give him a bath, but you'll do it resentfully.

    4. Re: Gamechanger by Anonymous Coward · · Score: 5, Funny

      The ac part really gets me. I grew up in a part of Australis where 40+ degree days (Celsius) in summer were pretty regular. And yet somehow we survived without any ac at all, just fans on really hot days.

      All it takes is decent insulation, a basic understanding of heat transfer (aka understanding why throwing open the windows and curtains when it's 45 outside and 30 inside "for the breeze" is a spectacularly stupid idea, but opening up all the windows later that night when the temp drops to the mid 20s is must) and not being a total wimp.

      So yeah, when is hear people talking about their desperate "need" for a/c it irritates me.

      Now git off the dried remnants of my lawn.

    5. Re:Gamechanger by wile_e_wonka · · Score: 5, Interesting

      Like the parent post said, "Musk is changing the world":
      Solar City lets you buy your solar panels for zero down and "lets you pay off your loan with monthly payments based on the electricity your system produces." So it ends up that the electric bill plus the Solar City bill add up to less than the old electric bill. You don't need a pile of money lying around to buy a modern home solar system. Non-wealthy people who do not care about the environment are signing up with Solar City simply because they'll pay less for utilities.

      So, yeah, Musk is changing the world--he's causing people who don't care about the environment to put solar panels on their house that a few years ago would have made zero financial sense. In case you haven't noticed, he also made an all electric vehicle drooled over by people who don't care about saving gas.

    6. Re: Gamechanger by paulej72 · · Score: 5, Informative

      But what was the humidity level? 40C at 30%RH is much different than 40C 90%RH.

  2. Can't wait to get this installed in my house by talexb · · Score: 5, Informative

    Great idea. My power supplier currently has rates based on TOU (Time Of Use - http://www.torontohydro.com/si...), and I'd love to be able to charge up the battery supply for my house overnight at cheap rates, then run off the battery the rest of the time.

    I just hope it's not going to be one of those "Only available in the United States" deals.

    1. Re:Can't wait to get this installed in my house by duke_cheetah2003 · · Score: 5, Insightful

      Have you calculated the cost difference in hourly rates, your yearly use and the total price of such a setup? How long will it take to pay itself back before you see any financial gains?

      IMHO, this is totally the wrong way to look at this technology. Personally I don't care if it's more expensive than conventional power, if I could install a small wind turbine and a few solars on my property and charge this battery, it's off the grid for my acre. Totally worth it. People need to stop thinking in terms of 'its more expensive than conventional power.' That is the wrong way to look at this, IMHO.

    2. Re:Can't wait to get this installed in my house by RingDev · · Score: 5, Informative

      https://www.we-energies.com/re...

      Up to 17 cents cheaper per KWH (22c day, 5c night).

      Assuming you blow 10kWh per day, primarily between 6am and 11pm, that's upwards of $2.20/day.

      If you move your entire 10kWh load to the battery system and charge it over night, it drops you down to $0.50/day.

      $1.70 savings per day. That's 2058 days to recoup the $3500 expenditure, or just a bit over 5 1/2 years. Over the ten year warranty period you'll save ~$3000, assuming electricity prices remain constant.

      -Rick

      --
      "Most people in the U.S. wouldn't know they live in a tyrannical state if it walked up and grabbed their junk." - MyFirs
    3. Re:Can't wait to get this installed in my house by AmiMoJo · · Score: 5, Informative

      Tesla give you a 10 year warranty and maintenance contract with the pack, so clearly these things are rated for more than 5.5 years of operation.

      Since the warranty is 10 years the MTBF must be significantly longer, to keep the failure rate low. It's interesting that the 10kWh pack is for "backup" while the 7kWh pack is for "daily cycling". I'd guess that the 7kWh pack is physically the same as the 10kWh one, only cycled 30% less to extend battery life.

      Realistically they would have to be looking at an average 20+ year lifespan to give you a 10 year warranty and maintain a profitable failure rate.

      --
      const int one = 65536; (Silvermoon, Texture.cs)
      SJW, n: "Someone I don't like, and by the way I'm a fuckwit" - AC
  3. unit mismatch by edittard · · Score: 5, Informative

    battery systems designed to store up to 10 kWh of power.

    kW is a unit of power. When you multiply it by a unit of time it becomes a unit of energy.

    --
    At the bottom of the /. main page it says 'Yesterday's News'. Well they got that right.
  4. The utilities have reason to be upset by DaChesserCat · · Score: 5, Informative
    Many of the utility companies, such as the ones in Arizona and Hawaii, are griping about people adding solar PV to their homes. These people have, typically, used Net Metering; any power they produce in excess of what they consume at any moment is fed back into the grid and, when their demand exceeds their supply, they draw from the grid. The utility company gets to "reimburse" them for the power they contribute. In some areas (California), 1 kWh contributed during peak hours = > 1 kWh they can withdraw during off-peak hours. But that's pretty generous; most power companies don't even like 1 : 1.

    If you put enough PV on your home, you can eliminate your electric bill. At which point, many utilities argue, the costs of maintaining the grid (that's rolled into your electric bill, but not as a separate line item) are covered by the less-wealthy. The poor are subsidizing the grid for the wealthy, they argue. And they argue, further, that they should be able to charge people who are using Net Metering even if they ARE producing as much power as they're consuming.

    Where I live, I pay a monthly connection charge ( < $20 / month) + $0.085 / kWh. In short, my electrical co-op breaks these out as separate line items on the bill. Even if I put in enough PV to go Net Zero, so long as I'm connected to the grid, I'm at least paying the monthly connection charge. The Arizona utility wanted a connection charge / kWh installed PV, to the point that the homeowners who installed the PV ended up paying the same, without or without the PV. In short, they wanted to eliminate any incentive to add PV and connect to the grid. They did get approval for a connection charge / kWh installed, but it was a fraction of what they wanted.

    In Hawaii, where power is routinely $0.39 / kWh (it's made, largely, from imported petroleum), solar PV and Net Metering are so widespread that entire neighborhoods are producing excess power during the height of the day. It's to the point where HECO gets to veto whether or not you can add PV to your home; you have to get permits from them and they're getting harder to acquire. Because the transformers which convert distributed power (typically lower frequency and higher voltage) to the household power (60 Hz / 240 VAC split-phase) are made to work efficiently, one-way. Going the other way, they are considerably less efficient. If you are a net producer and your neighbor is a larger, net consumer, you're supplying your neighbor and the local transformer simply converts less power going into that neighborhood. When the entire neighborhood is a net producer, the transformer has a problem. So they limit how much power can be produced in each neighborhood.

    I used to think this was all about the power/utility companies trying to defend their bottom line. That's still part of it, but I've come to realize there are technical reasons, too. Installing efficient, bi-directional transformers would require:
    1. installing a second, bi-directional transformer
    2. taking down the power to an entire neighborhood while they switch over
    3. decommissioning and moving the old transformer

    at considerable expense. And that latter part, well, you KNOW they're not going to let their executives and/or shareholders eat that cost. And many utilities are regulated, such that they have to get approvals for rate increases. Which aren't easy to get. So there's technical reasons AND financial reasons for the utilities to grip.

    Put a battery pack on your home, like one of these. Get an inverter which feeds excess to the battery and NEVER exports to the grid. The power company loses their only technical reason to gripe, because you are no longer doing Net Metering. At that point, it's all about the Benjamins.

    Indeed, if you get to the point where your home is truly Net Zero, long-term, you can go completely off-grid. At which point they no longer have a say in the matter.

    --
    ... by the Dew of Mountains the thoughts acquire speed, the hands acquire shakes, the shakes become a warning
  5. Re:2kW with a peak to 3? by Guspaz · · Score: 5, Informative

    No, you turn them all on at the same time and you draw the extra power from the grid. You're not going off the grid on a single 7 kWh battery pack. If you want to do that, they're stackable, up to nine of them.

  6. Re:Its twice as expensive as the competition by Anonymous Coward · · Score: 5, Informative

    The Tesla system consist of:
        - 10kWh batteries
        - 3kW? battery charger
        - 2kW-3kW ac inverter
        - grid disconnect (for backup mode)
        - 3000? deep cycles
        - 10 year warranty

    and you compare it with:
        - 10 kWh batteries
        - 500 deep cycles
        - 3 year warranty

    and wonder why your system is cheaper? Really??