TMC is an independent, primarily volunteer organization that relies on ad revenue to cover its operating costs. Please consider whitelisting TMC on your ad blocker and becoming a Supporting Member. For more info: Support TMC

Help with power wall

Discussion in 'Tesla Energy' started by Dr Doom, Jul 12, 2017.

  1. Dr Doom

    Dr Doom Member

    Joined:
    Jul 10, 2016
    Messages:
    248
    Location:
    NYC
    Hi:

    Need help with whether to purchase power wall with solar panels.

    I live in northern jersey and own my home that has backyard with southern exposure. There is no shade from nearby trees. I usually run an electricity bill from 200-300 dollars per month. We have AC, pool, one electric car to charge with four person household.

    I have talked to Tesla rep about solar panels and want to proceed with installation. My question is if it's worth it to get the power wall installed at the same time. Tesla rep told me that there would 30% tax rebate on the battery.

    What benefit is there for having a powerwall versus just having the solar panels? Also how many power walls would people recommend? Are most customers getting powerwall 2 or is there still a waiting list?

    Also can the power wall be kept outside year round? Thanks for help.
     
  2. TallPaulS

    TallPaulS Member

    Joined:
    Feb 28, 2017
    Messages:
    42
    Location:
    Colorado Springs, CO
    The 30% is because it would be included as part of your solar installation. This is correct regarding the federal tax adjustment, and the nice thing is there's no AMT exemption.

    As to whether you need one, it's highly dependent on your local utilities. Here in Colorado Springs you can make an agreement where any kWh you put into their network become credits that you can take out (at night, winter, etc) with no penalty or time based rate changes. So powerwall makes no sense here. But other states/munis may make economic sense to go off-grid.
     
  3. doubleohwhat

    doubleohwhat Supporting Member

    Joined:
    Sep 1, 2016
    Messages:
    406
    Location:
    Alabama
    It depends on your utility mostly but also on the size of the solar array you plan on installing as well as your typical house load during solar production hours.

    As TallPaulS mentioned, it can depend on how solar friendly your utility is. If they have a good net metering option then a powerwall may not make much sense unless you are interested in one acting as a large battery backup for your house.

    Now, if your utility is less than solar friendly (like mine) and selling excess energy back to the utility is not a good option then a powerwall could be used to soak up any excess solar energy produced during the solar production window and let you use it later on.

    One other thing to consider is whether or not you'll have enough excess energy produced by the system you install to warrant a battery. If you plan on installing a smaller solar system and your house has a fairly high constant load during the day then you may not produce more energy than what would be immediately consumed.

    If having the powerwall as a battery backup is an incentive for you then the decision is easier. However, if you already have a generator and the powerwall would really just be used to soak up excess solar energy then you would need to size your solar array to provide enough energy to both cover your house load during production hours and fill up (or mostly fill up) the powerwall. If you install an array that only produces an extra kWh or two during the production window then your powerwall will only be ~15% filled (again though, you could use the other 85% as an always available battery backup). On the flipside, if your house virtually no load during the solar production window then a large portion of your produced solar energy could be stored in a powerwall (or two, etc) for later use.

    Electric rates vary from place to place. So a dollar amount doesn't give us much to work on without some extra info. Your price per kWh and your average monthly usage (in kWh) would be more helpful. The monthly usage should be on your bill. Your true (with all fees, etc factored in) per kWh rate can be figured out from there based on the cost for the month.

    Yep.
     
  4. Dr Doom

    Dr Doom Member

    Joined:
    Jul 10, 2016
    Messages:
    248
    Location:
    NYC
    Thanks everyone for your help.

    So I have moved into this home and have only two real months of usage to compare numbers of power. this summer has been extra humid and hot so we are running AC more.

    For month of May- rather mild start of summer- I had used 1020 kwh or 174 dollars. In June- about 1880 kwh or 330 dollars.

    I have baseboard heating.

    So for power wall- it seems like it's more useful for people who are worried about power outages? like my goals on installing solar panels are to 1) reduce my carbon footprint 2) save on electricity bills. would having a powerwall really add to these two goals?

    also are prices for powerwalls going to come down significantly?
     

Share This Page