Small Solar Setup for The Sole Purpose of Offsetting Power Consumption?

Bonsaichop on 07/03/2021 - 18:28

Ahoy!*

Talking to a friend today about his rather low return on feeding solar to the grid, I was wondering if it is possible to get a small system installed (200-400 watts so only a couple of panels) for the sole purpose of offsetting the power consumed during the day? Wait hear me out..

In my scenario, we work from home running our own business. We would easily consume around 400+ watts of power per hour running our computers, test equipment, TV, lighting, making lunch etc during the 'full sun' hours of the day. I'm not interested at all in buying extra panels to feed into the grid for lacklustre returns, but would be quite interested if that first few hundreds watts of power could be offset.

But does any solar installer actually accomodate such a small system? Say 1-3 panels plus inverter.

I understand that depending on the day, cloudy days, winter, bird poop on your panels, neighbour's overgrown trees will depreciate the output. In fact I used to run a mini system just to power my NAS 24/7 as a practical thought experiment. However I was limited in placement of my 200w panel as it became grey if I could install it on our roof myself (for insurance etc).

Anyway, what might be the collective groups' thoughts on this? Am I missing something quite obvious (apart from a possibly stupidly high install fee?)

Many thanks! Look forward to reading replies!

  • Fun and useless fact: Did you know that the phrase 'Ahoy hoy!' was first suggested by the inventor (or should we say the person who got to the patent office first) of the telephone Alexander Graham Bell as the defacto greeting for using the telephone? Now you have a useless fact to pass on to your peers, friends and family! Or perhaps to drive them away….
Electrical & Electronics

Comments

  • MS Paint on 07/03/2021 - 18:30
    +4

    Wait hear me out..

    I stopped reading right here.

  • avoidfullprice on 07/03/2021 - 18:47

    With the labour cost you're about to pay, might as well grab some solar panels, inverter from Jaycar and hook up your equipment to it instead of mains.

    Am I missing something quite obvious

    That installer might not make enough profit from your system and so not entertain you. Back in the early days the solar system size is small and I often see houses with just a handful of panels on the roof. It is not unheard of to find exisiting system around 1kw but prob not a cheap inverter under 3kw these days.

  • holdenmg on 07/03/2021 - 18:50
    +1

    Maybe a battery to store the Power produced that you can draw down on is part of the solution.

    Get some costings/quotes.

    • Kangal on 07/03/2021 - 23:19
      +1

      Solar power generally doesn't have enough to run most equipment. Hence, why most people buy more panels, to try to increase this flow rate. As an analogy, think of it like using a smartphone to run an intensive Game that is stressing the Speakers, Display, CPU, GPU, Memory, and perhaps more…. and think of trying to keep it running by using a VERY SLOW wireless trickle charger.

      Hence, it makes more sense to capture all that slow energy, in something like a Lithium-ion Battery of Cells (power-wall), over a time period, and then using up that energy. The problem is that whilst you can get cheap panels (eg Camping ones), you cannot get cheap batteries (unless scavenged), or get a cheap inverter and let's not forget about labour costs. Yes, there are legal and safety implications to consider with electricity, especially at higher capacities.

      This is one of those situations where you really need to invest up-front, and reap the benefits eventually. Or to just forgo. It is not one to half-arse it. Environmental concerns not withstanding.

  • Ocker on 07/03/2021 - 19:00
    +3

    I think you are over simplifying the actual output you will achieve from such few panels.
    For example, we have a 6 kWh system installed and today it generated 20.1kWh over 14 hours, viz. an average of 1.44 kWh per hour. Therefore it would seem that a 400Wh system would only generate an average of about 100Wh per hour.
    During peak output hours our system averaged about 3kWh, meaning you would still be lucky to generate 200Wh.
    That aside, installation costs for a larger 2kWh would only be marginally more than your suggested system

  • plmko on 07/03/2021 - 19:35

    You are thinking about Solar the wrong way, suggest you go back and read up on why people buy so many panels.

    • deme on 07/03/2021 - 22:07

      Where should they go back to?

      • Quantumcat on 08/03/2021 - 09:18
        +1

        Solarquotes.com.au?

  • AndyC1 on 07/03/2021 - 20:01
    +3

    NO.

  • mskeggs on 07/03/2021 - 20:03
    +7

    The “lacklustre” feed in tariffs will pay off the system in 6 or 7 years without using any power behind the meter.
    If you are at home most days you likely use more than the average 22kWh an Australian home uses, albeit about half that usage is after dark.
    If you own the house, just get a 5kW system and enjoy the savings, don’t do the overthinking you seem to be doing.

    • mskeggs on 07/03/2021 - 20:09

      I should say, the rule of thumb is 1/3rd of the cost is labour, 1/3rd inverter and 1/3rd panels. Your plan only makes much of a difference to the panel costs, so you will still need the other costs, even if the inverter is a little cheaper, and labour can go home earlier after installing 3 panels instead of 12.

  • whooah1979 on 07/03/2021 - 20:06
    -3

    Small scale PV isn't profitable. Take the capital and invest it in appreciating assets.

  • Matt P on 08/03/2021 - 00:06
    +1

    The issue is that power companies seem to have different plans for people with solar vs people without.

    When we got our solar installed, our default rates seemed to go up etc..

    If you only install a very small system, you could potentially end up worse off.

    Max out the roof. A 6kw system seems do-able for $3k these days with reasonable brand equipment

    • SBOB on 08/03/2021 - 06:47
      +1

      3k
      reasonable brand equipment

      Need to add a couple more K than that unless you're buying Steve Waugh tv specials and the resulting quality and future Phoenix company install that gets you (and even that's more than 3k)

      • Quantumcat on 08/03/2021 - 09:18

        Maybe in Vic where there's good subsidies. My 6.6kw system was about 6.5k in Canberra

        • brad1-8tsi on 08/03/2021 - 15:28

          Our 6.6kw system was $3900 in Sydney. Mid grade panels. Mid grade inverter. Mid grade install. (Captain Green).

          The Steve Waugh special would require some close inspection before saying "GO"

  • spal on 08/03/2021 - 09:04
    +1

    I have seen someone in southeast Melbourne advertising older panels on Facebook marketplace. I am sure you will be able to get something for pretty cheap. But installation and compliance costs could be an issue. Older systems would not meet the electrical standards, without which you expose yourself to risk, and insurers may not cover you.

  • Youfah Mizzum on 08/03/2021 - 09:56

    You'd only pay a slightly smaller amount to get standard 6.6Kw system with a 5Kw inverter.
    That's the usual these days and you'll pay about $5000.

    Organise with a power retailer to get the best feed-in tariff you can.
    Whilst you'll generate more than you consume, you will get paid a small amount for that excess.

    I know that's not quite what you're asking but it's the better way to proceed. You'll likely never have a power bill again.

  • Keplaffintech on 08/03/2021 - 11:47
    +1

    The problem with your idea is that costs do not scale proportionally to the size of the system. This means for a 0.5kw system you're still going to be paying $$$ to get contractors out, have them install panels on the roof, run all the electrical wiring, install a 1.5kw inverter etc.

    May as well just go for a normal system and let the feed-in pay it off.

    Also, you don't run air conditioning on those hot sunny days?

  • brad1-8tsi on 08/03/2021 - 15:22
    +1

    I'd be asking the question as to why your friend is getting such poor returns.

    The 1.5kw system at my old house that peaks at 1200w on a sunny day doesn't get anywhere close to covering the power bill.

    The 6.4kw system that peaks at 4.5kw at my GFs house covers the power usage over the year but there are days when it barely gets to a 1kw output.

    A 0.5kw system on a small business or residence is about the silliest idea I've heard in a long time.

  • endotherm on 08/03/2021 - 20:44
    +1

    And what do you do on overcast days? You would still need a 1kW system to generate a couple of hundred watts when you need it. During winter you might only generate 1-2 kWh for the whole day. I doubt the cost savings of a smaller inverter would be worth it, compared to a larger one. As mentioned previously, the cost of tradies and installation would still be the same. You'd be better off trying to milk some of that sweet government incentive money to put in a bigger system while you can.

  • Isla Brown on 12/04/2021 - 23:54

    I would recommend consulting a solar installer who’ll help you decide what size solar energy installation best suits your needs and budget.

  • adgnetworks on 16/04/2021 - 11:20

    Ive got a small system to offset some day usage but you've got to calculate the savings vs the expense of procuring/installing the kit.

    I got a few panels for $40 each.. inverter for $800.. some fuses and wiring for $200.

    A simple calculation is say you're using 500W for 8hrs of the day at a cost of 25c for kwh = $1 per day

    So to recover your costs would take at least 3 years.

    If you spent a little more to cover more than just 500W and sold your excess energy you can potentially make your return on investment better/quicker.

    For me ive got both a hybrid battery diy system that covers 800W (man cave stuff) and a 13kw system on the roof that does the whole house as i want it to cover my large aircon, dryers/washing machines, dishwasher, ovens all during the day.

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