Melbourne Man Says Powerwall 2 Will Drop His Power Bill To $0

Image: Supplied

Melbourne's first Powerwall 2 has been installed at a three-bedroom, one storey house in Coburg. Brendan Fahey and his wife Josephine added Tesla's shiny new battery to their home to complement their existing solar panels, after Brendan calculated that the Powerwall 2 could take his energy bill down almost to zero.

Tesla's Powerwall 2 was announced in October 2016, a follow-up to the original Powerwall, launched in 2015. The new model has improved on the original in a number of ways. One of the biggest changes is a built-in inverter, where the original model required an external one. The Powerwall 2 almost doubles the capacity of its predecessor, upgrading from 7kWh to a full 14kWh (13.5kWh of which is usable capacity). With Australia's average household electricity usage estimated to be around 16kWh a day, or as low as 13.5kWh in Victoria, the Powerwall 2 is now offering enough storage for Aussie households to potentially offset their entire electricity bill, and perhaps even move off the grid.

This is what Brendan found when he crunched the numbers around adding a Powerwall 2 to his existing solar. "I did some calculations with Powerwall 2 by writing a little formula based on my solar production and electricity usage for each day from 1st December 2016," Brendan explains. "Starting with a 14kWh home battery I subtracted and added on the gains and losses as I went through the six months up until a few weeks ago. At no point in my calculations did the 14kWh battery run out. If I had owned Powerwall 2 during that time I would have had no electricity bill."

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Of course while Tesla and the Powerwall are big names in home energy storage, they're certainly not the only players on the field. One of the big stories the week of the Powerwall 2's launch pointed out that Tesla's shiny new battery had already been beaten on price by a competitor — an Australian made battery called the Ampetus "Super" Lithium. Based on SolarQuotes' solar battery comparison table, the Ampetus, a $2300, 3kWh battery has the lowest cost per warranted kWh of all the batteries currently on the market, at 19c. Tesla's Powerwall 2 is a close second at 23c per warranted kWh.

Taking into consideration the Powerwall 2's larger size and included inverter, which the Ampetus model doesn't include, the Powerwall 2 is still competing closely with the super cheap Australian model. For Brendan especially, the Powerwall 2's size was one of its biggest selling points. "The Powerwall was much cheaper than other batteries," he explained. "And at 14kWh it was a good size, which by my calculations would leave our power bills close to zero." The price was also a tipping point — with the improved model it was finally worth the investment. "I had considered batteries for a few years but they were too expensive. The new Powerwall 2 made my mind up."

Another key advantage to the Powerwall 2 over the original (or even over its competitors) is its integration with the Tesla app. While the app was originally designed just for Tesla's electric vehicles, it was recently updated with the capacity to connect to Powerwall 2 modules. The app lets Powerwall owners monitor their home energy system from afar, while also allowing input such as setting a minimum energy reserve in case of a grid outage. "It's really good that you can see what’s happening any time," Brendan said. "And I will check it multiple times a day."

Image: Supplied

While solar panels alone can provide some offset on a household's electricity bill by selling back to the grid in times of excess, Australian feed-in tariffs are disappointingly low. With the end of government incentives such as NSW's Solar Bonus Scheme or the Queensland scheme that awarded a premium tariff of 44c/kWh, solar owners are being paid pennies for their excess power. Brendan is getting only 5.5c/kWh from the energy he feeds back into the grid, though it's set to rise to 11.3c from July 1st.

With feed-in tariffs now four or five times less than the cost of electricity households purchase back from the grid, batteries like the Powerwall 2 are vital to making the most of home solar power. One of the early adopters of the original Powerwall battery, Nick Pfitzner, shared his story with us earlier this year. With the help of his rooftop solar and integrated Powerwall, Nick managed to cut his electricity bill by a staggering 92.2 per cent.

Tesla Powerwall (And Solar) Saved An Aussie Household 92.2% On Their Electricity Bill

$2,110.46 - that's how much the Pfitzner family says they have saved in power bills since installing a Tesla Powerwall 12 months ago, with the yearly bill for 2016 coming in at $178.71. The Sydney residents, who were the first in the world to install a Powerwall on their home, claim to now pay just 50 cents a day for electricity.

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Nick also integrated his battery with Reposit Power's GridCredits system — whereby energy stored in your battery is sold to the grid during price spikes driven by peak demand, at prices of up to $1/kWh. The earnings from these peak events are given back to Reposit customers as 'GridCredits', which provide a discount off their electricity bill. Brendan hasn't included any extras like this yet, but says that he is "currently looking at Reposit Power as a possibility."

With the fully installed cost of Brendan's Powerwall 2 sitting at $10,917, Brendan is confident in his investment. "The payback time I have calculated is around 7 years," he told Gizmodo. "But as energy prices rise this may lessen."

For Brendan, however, the incentive isn't just financial. As much as he wants to save money, he's also a supporter of Tesla's sustainable energy mission. "My motivation is to get my electricity bill as close to $0 as possible, and for the good of the environment, which is why I chose Powerwall."

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Comments

    How much solar does this guy have?
    I'm sure these numbers would be the same for our family. It would be the first 3Kwh that would make the most difference. The rubbish feed in tariff does add up with our summer bills often Zero, even without a battery.

    Last edited 12/06/17 10:09 am

      Care to elaborate?
      My maths might be bad, but even if I assume you get 100% sunshine with an above average 6kW system, you would only be able to generate ~7927 kWh, according to https://www.lgenergy.com.au/calculator/
      So, even if I assume that you used 0 kW for your self, which is impossible, (fridge/tv etc) with Melbourne's current tariff of 5c per kWh, you could only obtain $396.35 in a year, but you still have to pay the supply charge which is ~$1 per day, which equates to ~$31 but that excludes any actual usage or other bs charges they make you pay.
      Even if you're in another state where it's 6c, it's still only $110, but that's only possible if you never use anything, ever, in 365 days.

      Well, first thing first. When installing batteries, they do not connect your stove to the system or your fridge or hot water. Reason being if it is very overcast or rains for a week you cannot cook, bathe and the food in your fridge will.....Fact, there is no switch to flick to change over from mains to battery power, from what I have been told by battery sellers! Secondly This unit the owner is talking about coast about $15000 I won't worry about adding the solar. Say the owner is paying $0.30 for kw of power. In NSW I pay $0.19 ATM. So that is 14kw in battery reserve. Then you simply do the math. 14x30 per day = $4.20 per day, but realistically the owner won't use that much of the storage, but say they do so $4.20 x 365 = $1533.00 saving per year and that is if it is sunny 365 days per year, in Victoria fat chance, lol. So it will take 10 years for the owner to make their money back. And remember that has to be sunny every day for 3650, bahahaha. And this is not taking into consideration the cost of the solar panels cost which would have to be $7000.00 for a 10kw system. Why a 10kw system you ask? The solar generated is used during the day the left over generated power goes into the battery. BUT THEN THERE IS THE BIG CATCH. It takes 10 years to break even on the BATTERY ALONE. AND ONCE 10 YEARS IS UP THE BATTERY IS OUT OF WARRANTY . DON'T BE FOOLED PEOPLE It's worse than having a 10000 litre water TANK that holds $20.00 worth of water

        You realise that majority of adopters are not doing it for financial gain?

        I was onboard with you about the cost savings vs actual costings until you throw in your water tank remark. Water is not the same as power - apples and oranges. Having water storage - regardless of cost - is beneficial for the environment. Much as these battery walls are.

        We may only save 150 in water per year off our recycled water, but i can tell you that living with stage 4 water restrictions for a number of years - the investment is worth it and then some.

        Yes its expensive, yes you may not make your money back in the short term, but show me any other investment that does (yes i am opening up for abuse with that comment) Sometimes things need to be adopted to become mainstream, its expensive, very expensive.
        hopefully it will benefit the environment (although im sure the mining for the components outweighs the return in carbon or land destruction)

        Just leave water alone man, thats actually a great idea!

    That's great, now all I need is a house.

      Unfortunately every rented house and apartment will never get solar. Sad part is the list of the haves and have nots (home ownership) is growing bigger every year. Caused by nothing short of the insane second form of currency: housing investment.

    If you have solar and a battery do you still need to be connected to the grid? And if so how much is this per qtr?

      The number of panels you have would determine if you make more $''s from feeding in then the cost of a connection. If you are creating 14kwh a day in winter then no need to be connected. Not sure how many panels would cover that.

      $130/quarter no mater what your usage is. So no ones bill is ever zero unless you are lucky to have a 40c plus feed in tariff to offset it.

      At $10k this is getting much better, and I feel sorry for the early adopters of the PW1 as the PW2 was announced only 6 months after (before PW1 installs starting happening).

    I really can't see batteries taking off unless you use very little power and can disconnect your external electricity or you can make the money back on the Powerwall in 5 years.

      Its heading there. There is always a leadin period where its not financially better to invest in these, but at some point the cost becomes better and its a far easier decision.

      I'm pretty sure solar panels are mandatory for new buildings, at least in some states, and if so this is the next logical step, either by choice or legislation. You're going to see the cost of these reduce (in a range of ways), while the cost in other areas increase, and at some point its going to be a practical consideration.

      Just not yet.

      Mobile phones went through similar about 20 years ago, and look at them today. Most people either don't have a landline, or if they do they rarely (if ever) use it.

    So is this guy completely disconnected from the grid? If not then he's either lying or misleading. The poles and wires cost (which equates to close to half his bill) will still be there, regardless of whether he uses grid fed electricity or not.

    Breaking news, Melborne man neglects capital costs.

      Exactly and he still has to pay $500 a year supply charge just in case.

        And in other news, two people don't read an article in full.

        "With the fully installed cost of Brendan's Powerwall 2 sitting at $10,917, Brendan is confident in his investment. "The payback time I have calculated is around 7 years," he told Gizmodo. "But as energy prices rise this may lessen.""

          Not what I meant, but, perhaps I used the wrong term?
          I meant the cost of the money.

          Economics geeks, help me out here what's that term for the lost opportunity to use your capital in a safe competing investment?

    It would appear the title of this article is wrong or the article negects to include a key quote from the home owner. Brendan says "my solar production and electricity usage for each day from 1st December 2016," Brendan explains. "Starting with a 14kWh home battery I subtracted and added on the gains and losses as I went through the six months up until a few weeks ago." This does not mean that he said he will drop his power bill to zero.

    If he did then he is most likely wrong or we haven't been told the whole story about the household energy usage. We don't know what source they use for space heating, hot water and cooking. All this could be from gas. In which case wouldn't be hard to achieve, even in a cold Melbourne winter.

    There is also a big difference between obtaining a zero power (electricity) bill and having enough capacity to go off the grid. Clearly Brendon is relying on feed in credits, which strongly suggests that power will still be drawn from the grid.

    In a country with so much coal, with so much gas you'd think that it would be cheap but no. The governments that we elect to look after our interests instead put us last after themselves, and the profits of big corporations.

    Pennies? If they were back in the 1960s maybe...

    I have 8 solar panels, with a feed in tariff at 40c and low power usage so that the bill is almost always in credit. But even with all that it'd probably take upwards of 8 years to pay off one of these... And that's assuming prices, tariffs, and the efficiency of the panels continue as they are, which they certainly will not!
    I don't know about any special credit system with batteries here in WA. That would change things if there were such a thing here but I doubt there is.

    As it stands, despite the hard sell with articles like this batteries are just a bit too expensive to make it viable, especially when you factor in how much less they'll cost and how much better they'll be by the time you pay off your expensive out-dated version

    All the calculations I've done on this, the maths don't stack up. The batteries just don't last long enough to get a ROI. They need to be about half the price to make it worthwhile.

    What people are forgetting in all these calculations is that during the day you use your own solar FIRST before you use mains power. So the biggest savings come from the offset of both your daylight base load plus the peaks from using dishwasher, washer, dryer etc. we have a 5kW system facing due north with no obstruction and is summer we can generate almost 40kW hours a day, over a base load plus even AC of about 28kW on a 40 degree day. The savings are great because the AC uses the solar first and is thus saving about 23 cents per kW hour rather than. Feeding in at 5 cents. Ours was a $9000 system which will pay off in less than 4 years. That said, the battery economics don't yet stack up. The Powerwall 2 would need to be $5k or less to make it worthwhile.

    What people are forgetting in all these calculations is that during the day you use your own solar FIRST before you use mains power. So the biggest savings come from the offset of both your daylight base load plus the peaks from using dishwasher, washer, dryer etc. we have a 5kW system facing due north with no obstruction and is summer we can generate almost 40kW hours a day, over a base load plus even AC of about 28kW on a 40 degree day. The savings are great because the AC uses the solar first and is thus saving about 23 cents per kW hour rather than. Feeding in at 5 cents. Ours was a $9000 system which will pay off in less than 4 years. That said, the battery economics don't yet stack up. The Powerwall 2 would need to be $5k or less to make it worthwhile.

    Thanks for the article and also the many comments, most present food for thought. I'm looking at options to keep my lights on during the Feb/March 2018 electricity reserve shortfalls. As well as a heavily-silenced generator I'm also looking at Li-Fe-PO4 batteries which may have longer life and tolerate more charge/discharge cycles. Has anyone got info on the Vanadium Redox batteries please? They were going to save the world at one stage but seem to have disappeared.

    I'm out of touch with feed in tarriffs but there is a supply charge which you pay even if you don't use any grid power.
    Unless you are no longer a customer then you tell the power companies to FO.
    Also the battery would lose capacity over a few years and eventually have to be replaced and hopefully they will become cheaper by then.
    I'm interesed anyway but these are the questions I have. I'll read the article again when I get home.

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