Solar Panel and Battery Setup - Worthwhile with Rebate ?

curious101 on 24/04/2019 - 04:04
Last edited 24/04/2019 - 08:49

Hi All

I have been quoted total 13K for 6.6 Kw Solar (6K for Solar PV setup), with 2.4Kw dc coupled battery (7K for batter - 90% efficiency). My typical usage is 8.8 to 10 Kwh per day (single guy).

I am with Ergon paying 89 cents per day access charge and On-peak/Off-Peak plan, currently paying 25.298 with Ergon (Tariff 11).

QLD residents are able to avail 3K solar battery grant, which would bring my entire setup cost to 10K, and essentially the battery will work out to be 4K. Further, in QLD we have an interest free loan for 10 years for the remaining 10K. Please note that this is only available IF I out for a battery setup.

For my location the yearly average for sun is as follows, and I am planning North facing 30 degree tilt for the solar panel:
Sunny 107
Partly Sunny 148
Total 255 days with sun.

As the calculations got the better of me, I was wondering if someone has done the maths already, or if you understand the industry, whether it would be worthwhile for me to opt for this ? Suggestions to opt for setup with or without the battery, considering the interest free loan and 3K battery grant; based on facts, stats and economics, will be greatly appreciated.

Thanks a ton in advance.

EDIT: FIT rate - 0.08 cents.

Electrical & Electronics

Comments

  • [Deactivated] on 24/04/2019 - 04:36
    +6

    I'm not good at maths.

    If I got 10 cents for every maths test I failed I'd have 63 cents by now.

    • curious101 on 24/04/2019 - 04:45

      Haha, please someone post Udemy Maths course links for TightBottom and then you can help me after that :P

  • Nugs on 24/04/2019 - 06:24

    Solarquotes.com.au might have a calculator. They had a straight solar one when we installed 7 years ago.

  • pao2x on 24/04/2019 - 06:43
    +1

    Are you trying to achieve of grid? I did not see a FIT rate for your solar in your plan.

    If you go off grid you will be wasting an average of 12-16kWh per day that you can’t use or store. So with a Feed in of even 8c you will be losing out vs just solar, no battery and just feeding in. With battery you won’t recoup the cost even longer.Not very environmentally friendly either.

    PS. - I have not seen a scenario where battery has an advantageous ROI yet. Also 2.3kw will never survive a hot Queensland night with AC, not even more than a few hours

    • TheMindsetTraveller on 24/04/2019 - 07:29

      Can you explain the 'not very environmentally friendly' to a lay person ie me?

      And in terms of 'not seen a scenario where battery has an "advantage" ROI"
      1. are you referring to "advantage" as to when the benefits of owning a solar/battery (even if $0.01 better off) exceeds the cost base?
      2. and at what rough price point would it be advantageous? The OP said it is a $13K setup and you suggested it was not 'advantageous' … so either the price of the cost needs to come down (or electricity goes up / or feed in rates go higher), … but lets just say the cost needs to come down, at which point is is better off? $7k? etc

      • pao2x on 24/04/2019 - 09:45
        +1

        Not environmentally to go off grid with a 6kw solar and 8kwh usage because you will be wasting 10-20kwH of electricity a day, unstored and unused. It is a pipe dream to go off grid with 2.4kwH of storage- your aircon and fridge will finish that off in a few hours or less on a hot night.

        1)$7000-$3000= $4000 to recoup on the battery, you need more data on how you would gain that back by a "battery". I don't see how because off grid is not a realistic possibility. i.e you cannot get rid of connection charges.

        2) Same as number 1- you need to make a financial case, 4 grand versus your benefits. The battery itself does not generate anything. It does two things
        1- store energy so that you can use "cheaper or solar generated electricity) 2- it stores energy so you can theoretically go off grid (no daily charges) or if not off grid, the bonus of having power when grid goes down.

        Scenario 1- you store 2.4kwh of power for the long night, saves you a whopping 60cents a night assuming your solar electricity is free (it is not, you've paid for it and you can sell it) = $200 value a year, takes more than 2 decades to get your $4000 back and you have not even taken into account solar feed in tariff, interest, the battery will be dead well before that etc.
        Scenario 2-OFF Grid- save 89cents a day in daily connection charges, well you don't really want to live in the dark ages for most part of the night do you?

        Go solar, it usually gets your money back in under 5 years. Batteries however have a long way to go to making financial sense on 99% of cases

        • TheMindsetTraveller on 24/04/2019 - 10:24

          Thanks for that; so your scenario and hypothetical- the battery would have to be $1600 or less to be worthwhile? Assuming a battery might last 8 years? As I said I am a 'lay' person so don't know much about this. The more I read, the more confusing it gets - there is a plenty of "conflicting" information out there.

          For example, the next car I buy is likely to be 100% electric but there are some who say its not 'environmentally' friendly either. I mean, any car is going to be not 'friendly' anyway, considering any car will require obtain raw materials / making parts / assembling them. Then when the car is disposed, most parts are just thrown into waste. At least having electric power can be sourced renewably versus petrol (and oils) that are non-renewable.

          • pao2x on 24/04/2019 - 11:56
            +1

            @TheMindsetTraveller: Not even, that is assuming the solar generated is $0.00 in value. Then you will get your money back in 8 years. Put it this way if you put your money on a measly 1% savings account you would still be better of in 8 years and that is already assuming your battery saved solar energy is "free".

            Buying an electric car is a different variable altogether. It is effectively more storage and more use (both of which tips the scales in favor of the solar household). Buying an electric car would make a whole lot more of sense than a $7000 home battery.

            Just to illustrate how much bollocks a $7000 2.4kw battery is. A Hyundai ioniq has a 28kw battery @ $50,000 and you get a car with it. A nissan leaf has a 62kw battery @ approx $60000 (price to be determined on release)

            A recent study by ARK which is heavily Tesla inclined shows that in the US (power prices are up to 3x cheaper than Oz) and with US gov't subsidies, a Tesla Model 3 has less total cost of ownership than a Toyota Camry in 3 years. Assuming driving 24,000km a year, thats a whole lot of driving. Also assuming US$35,000 Tesla model 3 which has been so far a mythical Unicorn and Tesla does not really sell that model

            https://ark-invest.com/research/model-3-vs-camry
            https://cleantechnica.com/2019/04/17/tesla-model-3-is-cheape…

            Personally I would love an electric car. Maybe soon. And maybe when it can act as a Home battery as well

        • curious101 on 24/04/2019 - 10:41

          Thanks a lot pao2x, very insightful much appreciated.

  • SBOB on 24/04/2019 - 07:05
    +3

    The Roi on your system without battery will be much much better (i.e. achievable)

    There is no way that 2.4kw battery will ever pay for itself

    There aren't many setups where the price of the battery is justifiable in a $ sense

  • CheapSticks on 24/04/2019 - 07:54
    +2

    Not worth is given your low usage in my opinion.

  • ESEMCE on 24/04/2019 - 08:29
    +1

    I live in SA with 5kW array already on roof (2kW North, 3kW West), $5000 battery rebate and the worlds highest electricity prices (apparently) but Gas hot water.
    I've done the sums and it's still only breakeven (including interest) at around 8-9 years for our household.
    I would be better off financially to add a third array on our East facing roof to further shave down our imports in the morning.

    Even with Electric Hot Water, you'd likely be better off adding more solar and switching your water heating to daytime, using your hot water as your "battery" for excess power.

    • curious101 on 24/04/2019 - 10:42

      Thanks for this.

    • ESEMCE on 27/04/2019 - 19:47

      Forgot to add this earlier (although with a 2. 4kWh battery is kinda irrelevant).
      My calculations do not include any benefits that might arise in the future by connecting your battery to a Virtual Power Plant.
      Depending on the pricing of power sold into the grid from the battery in that future state, this might change the calculations, but probably only by a year or two.
      And once again this is in SA with +40c/kWh pricing and an extremely generous government rebate.

  • owli on 24/04/2019 - 09:51
    +1

    Just get an eligible battery that is closest to $3k. Otherwise, it does not seem to make much economical sense.

  • pao2x on 24/04/2019 - 09:53
    +1

    Also on a side note $7000 for a 2.4kw battery sounds like a total rip off.

    • SBOB on 24/04/2019 - 11:15
      +2

      It's like the price has been inflated due to the rebate … But that would never happen right? ;)

  • pao2x on 24/04/2019 - 12:02
    +2

    Just to illustrate how much bollocks a $7000 2.4kw battery is. A hyundai ioniq has a 28kw battery @ $50,000 and you get a car with it. A nissan leaf has a 62kw battery @ approx $60000 (price to be determined on release).

    $2916/kw of battery storage for that rip off of a battery
    vs
    $1785/kw on the Hyundai ioniq + you get a car.
    vs
    $968/kw on the Nissan leaf (hypothetically based on an estimate price) + you get a car

    a Tesla powerwall costs about $15000 installed w 13.5kw capacity or around $1100/kw

    • curious101 on 24/04/2019 - 13:31

      Thanks a milliom for this, never thought about it this way.

  • MikeKulls on 25/04/2019 - 23:28
    +1

    Without doing the calcs, batteries are generally a LOOOONNNNG way from being even vaguely economical. For a 2.5kwh battery you will be lucky to make 30c a day. For me with my prices it would be 15c. It's going to take long time to pay off $7000. You also need to factor in you could spend some or all of that money on a bigger solar system and make more on that. Or just put it in a term deposit and you're sure to make more than 15 to 30c

    • MikeKulls on 25/04/2019 - 23:31
      +1

      I just worked it out, that's 63 to 127 years. That is not an exaggeration, as others have pointed out $7k for such a small battery is a total con. I would avoid this company altogether

      • pao2x on 26/04/2019 - 01:07
        +1

        Agreed. Ripoff probably the solar too

      • curious101 on 26/04/2019 - 01:41

        Thank you MikeKulls, you are a legend. Grateful.

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