Home energy consumption versus solar PV generation

A previous article on this site looked at the first part of that answer, how much energy your solar cells will produce. Here we learnt that the amount of energy a 1kW system produces varies depending on where it is located in Australia.

The last two articles in this series have explored the second part of that answer; how much energy you consume in your home (“How do I use electricity throughout the day?” and How to save energy in your home).

They told us what we use our energy to power, when we use it, what uses most of it and also some hints on how to use less. Here we also learnt that the amount of energy the typical home consumes varies depending on where it is located in Australia. In this article, we stitch those two parts together to find the answer to the question of how much a typical home might export to the grid.

Consumption versus generation in Summer

The graph below shows three curves for an average Summer day in Sydney:

1) How much electricity the typical household would consume (the red line)

2) How much electricity a 1.5kW grid connected solar PV system will generate (the solid green line)

3) How much electricity a 3kW grid connected solar PV system will generate (the dashed green line)

How to interpret this graph

The graph below shows the amount of power being used by an average home, and generated by an average  solar PV system at any point in time during an average summer’s day. If the green generation line is higher at any point than the red consumption line, you are generating a surplus of power, and hence feeding that electricity back into the grid. When the green generation line is below the red consumption line you’re still generating, but not enough to meet your households demand, so you will be buying electricity as per normal to make up the difference.

Please keep in mind that kilowatts (kW) are a measure of instantaneous electricity usage/generation (e.g. right now your system is producing 2kW), whilst kilowatt-hours are a measure of cumulative electricity usage/generation over time (e.g. your system produced 6kWh of solar power today, and your home used 16kWh of power to run its appliances.) When referring to solar PV system capacity, the term kW is usually used–this indicates the ‘peak’ capacity of the panels or system; real-life production will likely be lower, depending on conditions.

Average NSW household in summer electricity consumption vs PV generation

Average NSW household in Summer – electricity consumption versus generation

The average production of a solar PV system in Sydney has been calculated using the online performance calculator for a grid connected system; PVwatts. The attentive eye will notice that a 1.5kW system is only producing just a touch over 1kW of power at its peak. This is not an error. The average PV system will export only around 75% of its rated power to the grid at its peak generation due to the variety of losses associated with the solar panel and inverter efficiency. The home electricity consumption curve has been calculated from grid wide electricity consumption data for NSW from the Australian Electricity Market Operator (AEMO).

A 1.5kW system

In the above graph we can see that a 1.5kW system will produce just enough power to very slightly surpass the average household’s demand at 1pm, when the sun is at its peak. The rest of the time, the average household uses more than the solar PV cells can produce. In total, the 1.5kW system produces 7.3kWh of energy, compared to total consumption throughout the day of 20.5kWh for the house (for the technically minded, the amount of energy produced is the area under the curve, because energy is the integral of power). Hence, in this situation virtually no power is exported or fed into the grid by your PV system (except for a negligible amount at 1pm) as it is all consumed by your home. This will save the money that you would otherwise have paid for electricity.

In a state with a net Solar Feed-in Tariff in place (where you are credited for the surplus electricity you export to the grid) the home with the above graph would have no Feed-in Tariff income. They would still, however, be saving the $1.14 in electricity that would otherwise have had to be paid for. Although both the average consumption and generation curves for a given individual home will be slightly different than depicted in this graph, this is more or less a representative example.

A 3kW system

The dashed green line shows the electricity generation of a 3kW grid connected solar system. As you can see, this is above the red line for the majority of daylight hours, meaning you will be exporting a good amount of energy to the grid. In total, the 3kW system produces 14.5kWh of energy, compared to total consumption throughout the day of 20.5kWh for the house. But because it is often producing more at any given time than the household can consume the 3kW system exports a total of 6.02kWh of energy to the grid. The rate you are paid for your surplus electricity fed into the grid will depend on which state you live in.

As a representative example, if this system was in Queensland, where a a net Solar Feed-in Tariff is in place, its owner would earn: 6.02kWh x 44c/kWh = $2.65 in feed-in tariff income (6.02kWh is the surplus amount of solar energy generated and exported to the grid) as well as save: 8.5kWh x 15.6c/kWh = $1.32 in electricity you would otherwise have to pay for. Giving a total benefit of $3.97.

However, if this system is located in NSW, where no state-backed feed-in incentive scheme is currently in place (only voluntary contributions of up to 8c/kWh from electricity retailers), the household would earn 6.02kWh x 8c/kWh = $0.48, plus 8.5kWh x 15.6c/kWh = $1.33, for a grand total savings of $1.81 for the day.

Consumption versus generation in Winter

In winter, the expected solar PV average generation curve is slightly lower than in summer, reflecting the lower intensity of the sun. Note that on a cloudy day generation will be much lower than depicted. In Sydney, where the sun shines almost perenially, this is not such a problem. Melbournians, however, are slightly less lucky. In this graph average household electricity consumption is represented by a blue line. For a discussion as to why it takes this shape, please refer to the article “How do I use electricity throughout the day?“.

Average NSW household in winter electricity consumption vs PV generation

Average NSW household in Winter – electricity consumption versus generation

A 1.5kW system

In the above graph we can see that a 1.5kW system will never fully meet an average household’s demand. In total, the 1.5kW system produces 5.3kWh of energy, compared to total consumption throughout the day of 26.7kWh for the house. Hence, in this situation no power is exported or fed into the grid by your PV system as it is all consumed by your home. Even if you live in a state or territory with a net Solar Feed-in Tariff in place, a house with electricity consumption/solar generation as in the graph above will not receive credit on its bill–instead, all of the energy bill savings will come from the avoided need to purchase power from the grid.

A 3kW system

The dashed green line shows the electricity generation of a 3kW grid connected solar system. As you can see, this is above the blue line for the majority of daylight hours, meaning you will be exporting a good amount of energy to the grid. In total, the 3kW system produces 10.5kWh of energy, compared to total consumption throughout the day of 26.7kWh for the house. But because it is often producing more at any given time than the household can consume the 3kW system exports a total of 4.02kWh of energy to the grid.

Under, for example, the Queensland Solar Bonus Feed-in Tariff scheme, the above household would earn: 4.02kWh x 44c/kWh = $1.77 in feed-in tariff income (4.02kWh is the gross amount of solar energy generated) as well as save: 6.5kWh x 15.6c/kWh = $1.01 in electricity they would otherwise have to pay for (6.5kWh is the amount of generated solar energy your house is consuming) Hence, in Queensland a 3KW system for an average household on a winter day has a total benfit to you of $2.78.

In a state with no government-mandated Solar Feed-in Tariff incentive such as NSW (where some retailers offer an 8c/kWh Solar Buyback rate), this 3kW solar system would earn its owners: 4.02kWh x 8c/kWh = $0.32 in Solar Buyback income (4.02kWh is the surplus amount of solar energy generated and exported to the grid) as well as save: 6.5kWh x 15.6c/kWh = $1.01 in electricity they would otherwise have to pay for, giving a total benefit of $1.33.

How should you use electricity to obtain the most benefit?

Obtaining the maximum benefit from your solar PV system requires a decent understanding of how you use power throughout the day and the feed-in incentives (if any) available to system owner in your state. State-based Solar Feed-in incentives have changes significantly since they began being introduced in 2008-2009. (Click here for an up-to-date list of solar incentives in all of Australia’s states and territories.)

Solar Feed-in Tariffs vs Solar Buyback Schemes

Although NSW once had a gross Solar Feed-in Tariff under the state’s Solar Bonus Scheme, all of the schemes currently operational in Australia (as of 23 May 2012) are net schemes, which pay only for surplus solar power exported to the power grid. The remaining programs come in essentially 3 forms: State government-backed Solar Feed-in Tariffs (SA, Victoria, and Queensland), 1-for-1 Solar Buybacks through electricity retailers (ACT, Tasmania, Northern Territory), and voluntary Solar Buyback schemes, which offer (often nominal) rates for exported solar power that are lower than retail electricity rates (NSW, WA).

You can read an overview of these schemes and how to take advantage of them here.


  1. Hi,
    I have installed 2kw 9panels recently & project on average 2500kwh per quarter. I live in Sydney.
    Can you please tell me when is the best TIME to use extra appliances eg dryer, dishwasher during summer & winter to maximise saving. Thanks.

    1. HI Melanie. What direction do your panels face? If they face north, (and provided there is no shading) midday is the best time to use appliances. If west–early afternoon. If east–late morning. Hope this is helpful.

  2. Hi, I have just installed a 3KW system in Post Code 2763 and cannot get my head around the metering. The solar mob have connected it to the old spinning meter which is going in reverse through the daylight hours. They will be installing a new meter in the next few weeks, is it a live system in the respect that I have to use the Kw’s up literally as they are being generated? I kind of thought that if I roughly use 2000kWh per quarter or 23.2 per day. AGL check the meters every 3 months and it would be like total usage – solar credit = kWh charged. If this false?
    Thanks, Scott

    1. Hi Scott,

      Are you on a Solar Feed-in Tariff, or did you sign up after the generous rates were axed? Your new meter will be able to measure how much power you export to the grid (if you have no Feed-in Tariff, you’ll be paid a small amount by your electricity retailer) and how much you draw from the grid (i.e. what you have to pay for.) Using your solar power as it is being produced will enable you to avoid purchasing electricity from the grid (imagine drawing from your solar system instead of from the grid). Your inverter will sort this automatically for you.

      Your bill will roughly be calculated thusly:

      (electricity drawn from grid in kWh)x(electricity retail tariff rate in cents) – (solar power exported to the grid in kWh)x(solar buyback rate in cents)

      Since electricity retailers in NSW currently offer only about 6-10c/kWh for solar power that you export to the grid, it is in your interest to use as much of the power as possible as it is being produced. This means changing your consumption habits as much as possible to coincide with when the sun is shining.

  3. Interesting to read some of these comments, it seems like a lot of people who already have solar like me were perhaps expecting more out of the solar/ or be saving more. Interesting also to read where you gave a answer for ravi, in regards if he should have a 1.5 system or 3.0kw system and that he should be using his power during the day that he would be better off. Now i am confused?

    i thought it was better to not use much during the day and let it go to the grid then buy it back or does it matter where you live. i am in adelaide, and i too have a pool and as i only got solar in 2012 i only get the 16c plus 7c from supplier=0.24c. In summer i would use around 1900-2100kw for approx 90 days, and i need to run pump for pool during the day, so is that better for me to use power during the day or night. What about say spring , autumn when i m not using pump as much is it better to consume power during the day or not. Confused? thanks

    1. Hi Joe,

      Sorry to confuse you. If you own a solar system, whether you want to aim to export your solar power to the grid or consume it yourself depends on whether you have a Solar Feed-in Tariff or not. You can read the details here, but in essence there are 3 scenarios which dictate how you should aim to use your solar power if you have a system. Keep in mind that when you have solar power (and even without) you should be much more careful about how much power you are using in general.

      1) You have a Feed-in Tariff which pays you more per kilowatt-hour for the solar power you export to the grid than you pay for electricity from the grid. You should try to export as much power as possible. You do not lose out if your solar power goes into the grid–conversely, if you weren’t going to use that power anyhow, you gain.

      2) You have a 1-for-1 solar buyback scheme, which offers you an equivalent amount of money per kilowatt-hour as you pay for electricity. A general regime of energy savings is advised, unless you have time-of-use metering and billing, where you pay more for electricity during peak hours and less during off-peak times.

      3) You have a solar buyback rate that is less than what you pay for electricity (such as in NSW or WA, where rates of only 8-12 cents per kilowatt-hour are on offer). In this case, you should try to use as much of the solar power as possible while it is being produced to extract the most benefit from your system. This is because the rate you pay for power from the grid is higher than what you can get for selling it.

      I hope this makes sense. May I ask what you’re paying per kilowatt-hour for electricity at the moment? Are you on a time-of-use billing plan, or an all-time plan?

  4. Hi,

    We live in NSW and recently purchased a K star 3kw system with 16 infi190m panels. there is a zero feed in tarrif at this stage with my provider so I will wait for the Ipart review to conclude and then decide to stay or move.

    Having monitored the import and export activity, we tend to consume 45kw per day and only produce 4.3wk per day. Today was indicative of that as it was sunny from 7am until 4pm so I expected a higher level of solar production.

    If we take into account the angle of deflection and level of efficiency etc, can I conclude that the maximum produced solar output for this day to be 3kw x 8hrs = 24kwh?.

    if this is correct then I have a major problem as the actual kw’s produced were 4.3kw for the full day.

    I would welcome your feedback.

    1. Hi Albert,

      Although the sun may shine 8 hours a day, the insolation is not ‘perfect’ for all hours of the day–not all sunlight is created equal! Depending on the angle of the sun to the panels, they will produce more or less power, a 90 degree angle in relation to the panels is best. So in the morning and evenings, although it’s light out, the sun’s rays are more diffuse from a stationary solar panel’s perspective.

      When talking about solar power there is therefore what are referred to as ‘peak sun hours’ (PSH). This is a convention that denotes the cumulative equivalent hours of ‘perfect’ sunlight that solar panels are exposed to throughout a day in a certain location. The maximum PSH you’ll get in the sunniest parts of Australia is about 4.5PSH as a daily average throughout the year–closer to half the 8 hours of sunlight that you’ve suggested could be the case. In the southern parts of Australia, the average annual daily PSH could be as low as 3.

      If you’re talking about a winter day in NSW, you could be looking at as low as 2.5 or 3PSH as well (if you noticed that low-output day recently, recall that we were pretty close to the winter solstice after all…) With a 3kW system on such a short but sunny day, even with a perfectly angled system, you’d only expect about 7.5kWh to be produced. This is a bit higher than what you’ve reported, but not as far off as 24kWh! There are other factors that could explain the discrepancy between the 4.3kWh you got and the 7-11kWh you should expect where you are, such as the angle of your panels, or the efficiency of products themselves–all systems have some inefficiencies.

      Hope you found this helpful.

  5. Hello,

    Firstly I found you article very interesting & easy to understand.

    We have recently moved to a farm in rural NSW & are running a 2KW off grid solar system with diesel generator back up. We have been having a few issues on cloudy days when we consume more power than we produce & hence at night have found it necessary to run the generator.

    I have checked our inverter & found it can run up to a 3 KW system. My question is, to upgrade to a 3 KW system is it as simple as adding more solar panels to my existing system or do I need to add battery capacity & other hardware as well?



    1. Hi Craig,

      Sorry for taking so long to get back to you, as you’re off grid the process of adding extra solar capacity is much easier. The final answer to your question would be best answered by going back to the company who originally installed the system if you have that information.

      If you have dual maximum power point tracking on your current tracker it may be as easy as adding new panels if not your issue will be the age of the existing solar panels as the efficiency decreases over time and new panels will only operate as well as the worst existing panel.

      If you’re looking to significantly increase the energy you produce you may be wise to invest in a separate system and upgrade your battery.

      Hope this helps

  6. Hello Sirs,
    I have been advised to install at least 3 kW solar systems. I live in NSW Post code 2475 and my avg consumption per quarter is 1730 KWH. (Avg bill approx $ 500-550). Since there is only 6c feed in Tariff at NSW, would it be idle to go for 3KW system or just stick to 1.5 KW.

    I also have 800 watt pool pump that needs to run approx 8 hours a day, however good thing is my hot water system has been connected with off pick meter at only@ 7.28 c).

    Please suggest me whether I should go with 1.5 KW or 3KW Solar system.

    Many Thanks in advance

    1. Hi Ravi,

      Thanks for your query. Whether you should opt for a 1.5kW or 3kW system would really depend on how you use your power during the day and whether you think you can shift most of your consumption to the daytime (excluding your pool pump, which it sounds like you’ve already sorted out). I’ve worked out that you must use on average (1730kWh / 91 days =) about 19kWh per day, but you would need to determine how much of this you’re using during the daytime (during sunshine hours).

      Because, as you mention, the current NSW Solar Buyback rate is much lower than retail electricity tariff rates, it makes sense to try to consume as much solar power as possible while it is being generated. This will save you having to purchase money from the electricity grid.

      In your postcode, a 3kW system would generate about (3.5 sun hours x 3kW =) 10.5kWh / day, so a 3kW would not be out of the question for you provided that you ensure you’re using it all and not allowing it to go into the grid.

      If you’re still looking for a system, feel free to call us on 1300 78 72 73 or fill out the form to the right of this page to get a free, instant solar quote comparison for installers in your area. Our services and advice are 100% free to our customers.

      Hope this has been helpful.

  7. Hello,
    I am looking to install a 5kw system in Perth, my average consumption is about 22 units per day, how much electricity would this produce?

    And if the system costs 10k is it worth it?

    1. Hi Lucas,

      A 5kW system in Perth will produce approximately 20 kilowatt-hours (kWh — electricity units) of electricity per day on average throughout the year. This number will be higher in summer and lower in winter, and ultimately the output will depend on how efficient your system is–for example, if the orientation and tilt of the panels are at their optimum, and if all your system components are functioning as they should.

      Right now, $10,000 is a reasonable amount of money to pay for a fully-installed 5kW solar system, depending on the quality of components. Solar system prices have been coming down steadily over the past few years (5kW systems used to be 2-4x their current price when Solar Choice first started assisting customers in 2009!), and seem to have settled down at around $2 per watt for a decent system, although it is possible to get systems for even less.

      Whether the system is worth the price depends on 1) the space you have available to install it (there’s no use in putting solar panels up on a totally shaded roof) and 2) the quality of the components you use (there are some really dodgy parts out there on the market). For $10k you should be able to find a good quality system.

      Solar Choice can help you to do so–we have a network of installers across the country, including Perth. Fill out the form to the right of this page to receive a free and instant Solar Quote Comparison from solar installers who operate in your area.

  8. Hi admin

    thank you for a lot of great insigt. i am student trying to do an analyses of the solar market in NSW and there for i would like to map “The home electricity consumption curve” as you have done, but on a monthly scale, and then compared it to the expected return from a solar cell. Do you have a more precises refference to the AEMO data because i can only seem to find overall demand data.

    all the best

    1. Hi Marc,

      Probably best to try to get in touch with AEMO for that one! Great chance to make a useful connection/contact point for future information as well!

  9. I have just had talks with an installer and he says i need a 3kw unit which will be enough for me to cover my power bill with some left over. I currently use 25.97kwh per day. he says where i live i have on average 10 sun hrs per day. I live south west victoria. is all this infomation correct. unit price 17k with rebate of 5k, approx cost 12k , is this comparable with other units
    Just need to make sure all above board.

  10. In NSW, I plan to install a grid-connected solar PV system. I have extermely variable energy consumption pattern at my house.

    What the most commonly installed solar system capacity in our state (1kW, 1.5kW, 2kW, 3kW, 4kW or 5kW)? Pls provide me a link to read more information if available.
    Why (I like to go for the most popular one in Aus)?

    How much space on roof needed for each system (1kW, 1.5kW, 2kW, 3kW, 4kW and 5kW)? Pls provide me a link to read more information if available.

    What is the rough estimated cost for each? Pls provide me a link to read more information if available.

    1. Hi Samitha,

      Thank you for your comment. To answer your questions:

      1) What size system is best for you depends on your energy consumption. Since the NSW Solar Bonus Feed-in Tariff scheme ended (and was replaced with nothing), Solar Choice has been recommending systems that just cover home energy consumption, as NSW residents who go solar now will receive either nothing or only a nominal rate for each unit of electricity that they export to the grid. Generally speaking, a lot of NSW customers have been opting for 3-5kW systems. We are also witnessing this trend in our customers elsewhere as well.

      2) Unfortunately I can’t give you a general answer to this question because the size of each solar panel varies with efficiency. Less efficient panels take up more space, while more efficient panels take up less space on a roof. You also have the option to split panel arrays between roofs, if you have, for example, a shed or granny flat.

      3) The price of solar PV systems is coming down globally and across Australia. You can receive a free and instant comparison of solar quotes for 1.5, 2, 3, 4, and 5kW systems by filling out the form to the right of this page. Depending on where you live, the comparison will include up to 8 different installers, and we have more in our network.

      I hope you find this helpful.

  11. Hi. I plan to install a 3kw solar panel system with 300watt panels but not sure how much energy it would generate per day. My house uses about 20kw per day. Would a 3kw system be suitable for me. I’m living in Adelaide. Thanks

    1. Hi Cathy,

      In Adelaide you can expect to get about 5.6 sun hour per day on average over the year–more in summer, less in winter. If you have a 3kW system, you can expect (5.6 * 3kW =) 16.8kWh. In the summertime you will generate more than this, however: (7.8 sun hours * 3kW) = 23.4kWh.

      Is your plan simply to reduce your electricity bill, or to eliminate your electricity bill completely? A 3kW system would reduce your bill significantly if you time the use of your electricity wisely.

      Also keep in mind that South Australia currently offers a Solar Feed-in Tariff rate of about 23c/kWh, net. This means if your system feeds electricity into the grid (i.e. you don’t use the solar electricity when it is generated), you will be credited 23c/kWh on your electricity bill.

      Also feel free to fill out the Solar Quote Comparison request form to the right of this page. You will receive a comprehensive comparison of the solar systems on offer from the solar installers available in your area.

  12. Hi Kobad,

    I live in Perth and have installed a 3KW solar panel system. The system has been operating since 26th June 2011 but unfortunately both Synergy and Western Power true to form were tardy with installing the new two way meter in the first place ( installed 15/7/2011) and then I was advise by Synergy on 4 August 2011 that they failed to programme the new meter so Synergy cannot read the production from the panels. I have been waiting since 4 August 2011 for the meter to be reprogrammed (today is 26/8). They have agreed to compensate us for their ineptitude but I need to have some reasonable basis to charge Synergy for the estimated nergy production. Can you suggest how I could make reasonable assumptions to calculate production from the panels since 26/6 or since 15/7 when the meter was installed. Our winter usage is about 30 units per day. Look forward to your advice. Mel

    1. Hi Mel,

      That’s a tricky one, and would depend greatly on when you think you actually use your power, since the WA feed-in tariff scheme is a net one.

      As a very, very rough estimate, you could make the assumption that you are producing (avg of 2.8 peak sun hours from June-Present * 3kW =) 8.4kWh per day, although the actual number is probably less than this. Is there any way you can calculate on average how much of this you use at what time of day? This will vary depending on whether people are home during the day or not–does anyone work from home or take care of kids during the day?

      Otherwise you could simply assume that you feed half your electricity into the grid and are therefore eligible for (4.2kWh * 44c/kWh =) $1.84/day on the 44c/kWh FiT, or if you are on the 20c/kWh FiT, then (4.2kWh * 20c/kWh =) $0.84/day. Multiply this by the number of days and subtract it from your power bill over the appropriate timeframe.

      Seeing as how you haven’t got any other basis for your calculations, it will all be based on your honesty in the end.

      Hope you find this helpful. Others, feel free to leave your own suggestions.

  13. I intend to install a grid connected photovoltaic system( 22 photovoltaic panels each generate an average 0.4 kWh per day) My house energy consumption is 40 kWh/day. I wonder how much energy can be saved for 20years periods if photovoltaic panels are installed.

    1. Hello Hung,

      Thanks for the comment. The answer to your question depends on the type of components (especially inverter and panels) that you have installed. Using the numbers you gave me, I can do the simple maths and estimate that over 20 years, your system would generate (0.4kWh x 22 panels x 365 days x 20 years =) 64,240kWh. If you use 40kWh/day, then again, your consumption over 20 years would be (40kWh x 365 days x 20 years =) 292,000kWh. 292,000kWh – 64,240kWh = 227,760kWh of electricity that you have to pay for during the course of twenty years.

      Now, please be careful because the numbers are actually much more complicated than this. Depending on the type of solar panels you have, you’ll have to think about gradual efficiency degradation, which is unavoidable (this is the reason panel manufacturers offer stepped warranties of 10 and 25 years, usually.) You’ll also have to think about other imperfections such inverter inefficiency, heat tolerance, and the effects of shading, not to mention the fact that the sun does not always shine when we would like it to. The amount of electricity saved may actually be less than the 64,240kWh quoted above.

      Without details about what kind of components you are using, I can’t help you with the details. But if you are still interested, please feel free to get in touch with us directly on 1300 78 72 73, or fill out a free quote comparison request form to see what deals are being offered from installers in your area.

      Hope this was helpful.

  14. Hello
    I have a 1.5 kw installed and looking to place a second system of 4kw in place so both system run together what would the cost be for the 4kw complete system please

  15. Thanks for your prompt response! From reading the Energex blurb, it appears that they have to install the meter so it can be connected to the grid (and that hasn’t happened yet). Insofar as it assists your response, the system installed is 1.48 KW with a 2.8 KW Xantrex inverter and 8×185 watt Sopray panels.

    On that note, what would it cost (approx) to add, say, a further 8 panels so I can bump up the energy production?


    1. Hi Russel,
      Thanks again for the comment. How much it would cost is dependent on how much an installer would charge you for their services, plus the going rate for panels, of course. Please also keep in mind that, depending on the state you live in, your eligibility for any applicable solar feed-in tariff may be altered if you increase the size of your system after initial installation.
      If you want to get in touch with one of our brokers (1300 78 72 73) would be happy to have a chat with you about which installers in your area might be able to help you.

  16. This is slightly off topic, but I have had a 1.5 KW system installed (in Qld) recently but not yet connected to the grid. What is happening to the electricity being generated? Is it still reducing my consumption during the day?

    1. Hi Russell,

      That would depend on how your system is set up, but a likely scenario is that you are using the electricity being generated, and that this is offsetting the cost of your electricity bill. What kind of metering system have you got in place? Also, do you have some kind of solar array monitoring system installed so that you can see how much your solar panels are producing?

  17. On average, my home uses 27.9Kwh/day, which means I pay about $3.5 a day. If I install a 3kw system, then how much profit will I get?

    1. Hello Ngoc,
      Thanks for the comment. It would depend on your location. You may not get any profit, but you will save money on your electricity bills.
      Which city are you in?

      1. Hello, i was just reading ur article and wondered that my house is spending daily kilowatt hours of 29.3, if i were to install a 1.5 kw/h system what will be the effect on my bill, if live in Sydney Australia.

        1. Thanks very much for your inquiry. In response to your question, a conservative estimate of the production of a 1.5kW system is Sydney is approximate 6kW hours per day. Therefore in order to comfortably offset your house’s usage you would require a minimum system size of around 7kW. Alternatively you could implement a smaller system with the intention of simply reducing your electricity costs. You can fill out a quote comparison request form or call us on 1300 78 72 73 for a chat about your options any time!

  18. I’m in NSW. I don’t understand your line “As well as save $1.14 in electricity you would otherwise have to pay for”.

    I understood that I sell all the electricity I generate back to the grid, but I have to pay regular prices for what I use.

    1. This is a method of allowing people to see the ‘real’ return of the system because the life-cycle-costing of the solar panel includes the revenue it creates by generating electricity and the opportunity cost of consuming electricity. Because in this case it is not a cost incurred it is an additional saving and therefore can be added to the revenue to give a more accurate representation of the return on investment.

  19. Dear Kobad,

    Thank you for the useful article and provided information. I still wonder why in your gross feed-in-tariff you first calculate the income from exported eletricity and then add the expence for the consumed electricity (e.g.
    5.3kWh x 60c/kWh = $3.18 in feed-in tariff income

    as well as save:

    5.3kWh x 15.6c/kWh = $0.83 in electricity you would otherwise have to pay for

    Hence, in NSW a 1.5KW system for an average household on a Winter day has a total benefit to you of $4.01.

    Aren’t we paying the consumed 5.3kWh x 15.6c/kWh = $0.83 and only getting the 5.3kWh x 60c/kWh = $3.18, which makes the total benefit $3.18-$.83 = $2.35 only and not $4.01?



  20. Hi Kobad,Just wondering if I used 10000 kw of power a year how would I save by installing a 1.5kw solargrid to my house.Thanks Tom

    1. Hi Tom. That all depends on where you live. Different locations get varying amounts of sunshine throughout the year. Also, your energy consumption is measured in kWh, not kW, which indicates capacity. For example, 1.5kW system run for 3 hours in perfect sunshine and at the perfect tilt angle would ideally produce something around 4.5kWh of electricity.

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