The Numbers Are In: Tesla Powerwall Can Save Thousands On Your Power Bill

How much can a family living in a four-bedroom house save by using the Tesla Powerwall and good ol' solar power? The figure has come in at $2110.46 a year for the Pfitzner family. Here are the details.

Tesla introduced its Powerwall battery unit that can store solar energy to Australia last year.

Natural Solar helped the Pfitzner family installed the 7kW Tesla Powerwall battery back in January 2016 along with an array of 5kWp solar panels. The company also installed a SolarEdge inverter and implemented a cloud-based power monitoring software.

The family, based in Sydney, has since managed to reduced its total power costs by 92.2%, amounting to an annual saving of $2110.46.

Image: Supplied

The family's average power cost was $572.29 per quarter in 2015. It has now dropped down to $44.68 per quarter. In October, the Pfitzner's power bill was in credit $50.25.

But the Tesla Powerwall and supporting hardware are not cheap. The Powerwall and solar panels will set you back around $14,000 (that's excluding GST) from Natural Solar. That's just the starting price. Nick Pfitzner told CHOICE that he paid $15,990 for his system. it's a huge investment, even when you can pay it off gradually on a payment plan. You can get two 300cc motorcycles with that much of money (sorry, I couldn't help myself).

However, the Powerwall does kind of pay for itself - it will just take some time.

The Pfitzners sell their unused electricity back to the grid. Nick Pfitzner told CHOICE:

The system will power whatever the house needs first as a priority, then it will fill the battery as a second priority and then anything over it'll export," he tells CHOICE.

The aim is to try and export about three times of what I import because my electricity cost is about three times [as much].

The rate for selling electricity back to the grid is usually around 8c per kWh, but since the family spent an additional $800 to installed a Reposit monitoring system, they are able to bump that price up to around $1 per kWh, depending on demand.

According to Natural Solar managing director Chris Williams, based on the Pfitzner's first 12 months of power bills, the return on investment and payback period would be six years. The Pfitzners said it may take eight years.

"With Tesla Powerwall 2 installations expected to occur in a matter of weeks, the anticipated ROI of solar and battery combined will only improve as the market mature," Williams said.

Are you considering getting a Tesla Powerwall for your home? Let us know in the comments.

Tesla Powerwall: 2016 Pricing Number Crunch and Payback Times

Back in May, 2015, we crunched the payback figures for the Powerwall, based on an assumed Australian cost and example electricity prices. Now there are local installed costs available, we have broken out the calculator and gone over the figures. The question is, can the Powerwall give a decent payback time?

Read more


Comments

    Ah... but how much debt are they in to pay off a solar and battery system? Tesla powerwall system is $14k, quick google search says a 5kw solar system is about $5-6k so unless you happen to have over $20k just laying around, the electricity savings is quickly negated by the cost of repayments to either the solar company or the bank.

      Yeah, I did mention that it does cost an arm and a leg. I certainly don't have a $20k+ lying around!

      The Powerwall and solar panels will set you back around $14,000...

      I checked about a month ago and the powerwall itself was around $10k from memory. $4k seems about right for a 5kw solar system, so the total price of around $14k for this particular install seems legit. Still expensive, but I don't think it's $20k as you're stating.

    I call BS. The powerwall cannot account for that electricity bill saving.

    A $14,000 6kWh Powerwall can (at best) power 6kWh each day.

    Lets make things easy and assume on-peak rate of 25c/kwh, and the powerwall gets filled to capacity every day for free.

    6 x 25c/kwh = $1.50 per day saving (at absolute best).

    $1.50 x 365 = $547.50 per annum saving.

    Or, about 23 years to pay back your powerwall.

      But..and I'm not going in to bat for this article...if you have solar panels and a powerwall, and your panels offset your usage during the day while charging the battery, you could save much more than that as you are only using the battery power at night.

        Yes, but in that case you don't really need the battery. They could've spent a fraction of the total install cost on the solar which (by the looks of their bill) totally offsets their daily usage and earning some pocket-money from a 4c/kWh Feed-in-Tarrif. Giving a much better ROI than adding a $9,000 Powerwall into the mix.

      Having battery storage also allows you to sell back to the grid at higher prices during peak periods.

        Yup. I've already updated the article with additional information about this.

          You are not allowed to export to the grid from battery storage, so you had better remove that info. ;)

            They aren't exporting from the battery. The system will power whatever the house needs first as a priority, then it will fill the battery as a second priority and then anything over it'll export The panels export, after they have filled the battery.

        I'm not aware of any retailers with tiered Feed-in-tariff pricing. It's usually a set rate (4-6c/kWh for anyone who's recently signed up) at any time of the day.

        If the example family had just purchased the solar array and offset their nightly power use with the standard Feed In Tariff, I think they would've had much the same result as above, but with a $5,000 investment, not a $14,000 investment.

      Actually you're missing out the fact that if it wasn't stored you'd be exporting it for approx 4-6c kW/h so the saving is say around 20c/kWh.

      The other thing you're missing out is that if the load exceeds power generation (e.g. multiple power hungry appliances running at once) then it will use power off the powerwall instead of pulling from the grid.

      It's very complex to account for the ROI with/without the powerwall itself but easier for a solar installation.

      I'm not sure if the $14k includes the panels? I was quoted around $6k from a reputable installer for a 3kW system so that might just be the powerwall only (article is a bit ambiguous). The company said the ROI is 6 years and they must know the total cost of installation but 6x$2110.46 = $12k?

      All in all quite a confusing article that sounds more positive than it should!

      However, having said that early adopters such as this family is good for everyone. Hopefully once the gigafactory is in full swing and with improved efficiency a battery installation will be a practical choice for everyone!

        Hi there,

        $14,000 is inclusive of the solar panels, according to the company that installed the Powerwall for the family. Sorry if that was confusing. I've clarified this in the article.

        Cheers,
        Spandas

          Sorry, my reply above assumed it was $14,000 for the powerwall alone. I understand now it was $5,000 for the solar and $9,000 for the powerwall.

          That changes many of the numbers above, but not the conclusion: By installing Solar, people can enjoy a 4 year to 10 year ROI depending on their usage volume and timing. By installing a Powerwall, the ROI is more like 22 years, which is much longer than the warranty period, and probably longer than its battery life.

          Until a 6kWh Powerwall sells for $2,000 - $4,000, it's a waste of money.

        I actually intentionally didn't include the potential feed in tarrif, because it makes the numbers even worse.

        There's a very good ROI for solar. I, personally, save about $500/qtr thanks to a 5kWh solar array. I'm just saying the family above would've been better off just buying the solar and leaving the powerwall on the shelf.

    That amount of saving cannot be explained by the Power Wall alone. It's very, very hard to get into credit unless you are on one of the ridiculously generous feed-in tariffs, which are now impossible to get with a new solar installation on Energex in QLD at least. Also coupled with the fact that you're not allowed to feed in from a battery, the saving will be marginal.

    But what is the expected life of the battery? This must be factored into the equation as well. If the battery won't last until at least the end of the payback period, then all this is pointless.

    Be nice on the ROI, I'm sure that is what he told his wife to get it in the first place. You'll only get him in trouble. 😁

    Step 1). Get high cost plan year in advance of solar purchase
    Step2) show how much you are spending in electricity and gasp at the obsurtity.
    Step3) convince wife you need solar and Tesla power wall
    Step4) become coolest guy on the block

    How about you look beyond the immediate financial cost?
    By generating your own power you're also protecting yourself against future rate increases from the power suppliers.
    The cost of solar set ups is already coming down in price, yet the cost of buying power from the grid is increasing.
    And don't forget about the not so selfish benefits of helping the environment.
    Sure, not everyone can afford this kind of set up but plenty of people spend $14,000 on a jet ski, boat or other toys that they don't really need.
    This country needs to look at the bigger picture and plan for the future.

    Solar power still isn't really viable. Those currently benefiting are basically the recipients of large middle class welfare subsides that the rest of us paid for. Feed in tariffs continue to be dropped. Its still based on a lot of dodgy wishful thinking scenarios ($1 per kWh feed in anyone?)

    Just the time for paying off the system. User says 8 years (and that seems pretty optimistic). Except the 8 years is actually 12 when you factor in the money forgone from the $16000 up front plus missed ability to invest that $16000 each year (5% return).

    The Pfitzner's will have to wait 12+ years before they get to break even. After that then yes they will have power bills of $100 a month (maybe). Hopefully they don't decide to move house or the system needs repairing (or replacement!) in that time.

    So many naysayers!! The basic fact, stated in the article, is that they were previously paying $572 / qtr and are now paying $44 /qtr. Whatever has changed ( and they believe it's the Powerwall) must account for the difference in their quarterly power costs. We can agonise forever on ROI, costs/KwH, rebates, tariffs etc, but the outcome is still the same for them.

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