Don’t Install A Smaller Solar System To Get A Higher Feed In Tariff. Here’s Why..

Solar feed in tariffs and system size limits

Finding a high feed-in tariff is becoming harder. Our feed-in-tariff comparison tool makes the job easier, but increasingly electricity retailers are putting system size limits on their most generous solar feed-in rates.

In South East Queensland, New South Wales, and South Australia, some retailers’ highest solar feed-in tariff is only available to systems below a certain size – typically 10 kilowatts.  This may tempt you to install a smaller solar system than you might otherwise. I recommend against this because:

  • You are likely to make more money with a larger solar system even if it receives a lower solar feed-in tariff.
  • Retailers can change their tariffs at any time. Once your contract is over, you can lose your higher feed-in tariff and be stuck with a smaller system.

And most importantly:

  • Larger solar power systems are better for the environment.

At this point, the typical Australian homeowner is thinking,

“Ronald, helping the environment is nice – but show me the money!”

I hear you. Now I’ve mentioned the most important factor, I’ll discuss money for the rest of the article. 

SE QLD Has Most Competitive Size-Limited Plan

A retailer solar size limit is simply a maximum size your solar power system can be in order to use a particular retail plan.  You are under no requirement or obligation to meet this size limit, unlike the connection rules for your location, which you must follow1.

How size limited plans compare to plans without restrictions on solar system capacity varies by state:

SA:  I’ve found three retailers offering plans with size limits, but their feed-in tariffs and charges aren’t better than competitor plans without limits, so if you’re interested in maximizing savings, I see no point in worrying about them. 

NSW:  The highest feed-in tariff offered by a size-limited plan is from AGL and is 0.4 cents more than the highest unlimited competitor plan I’ve found.  This under half a cent difference isn’t a strong incentive to even consider installing a system within it. 

South East QLD:  One retailer, AGL, offers a size limited plan with a feed-in tariff one full cent more than the highest competitor without a size limit.   

Some may consider the slightly higher feed-in tariff available in NSW makes it worth getting a smaller solar system, but I wouldn’t worry about it.  While there can be a small benefit to removing a panel or two from the design, I don’t recommend basing decisions on a tariff that the retailer could change at any time. 

This leaves South East Queensland as the only location where a reasonable case can be made to slightly reduce the size of the solar system’s design to get a higher feed-in tariff.  But even there, I don’t recommend it.  One reason is the higher feed-in tariff only exists at the whim of the retailer, but also because:

  • The cost per watt of solar power systems usually decreases with size, increasing the financial benefit from a larger system.
  • Larger solar systems help future-proof your home for when you decide to get a battery or an electric car or two.

But I’ll go through the numbers with an example household, and you can make your own decision.

System Size Limits Have Grown

The smallest limit I know of is currently 10 kilowatts of total solar panel capacity from AGL’s size limited plans.  In the past, there were plans with a size limit of 5 kilowatts of inverter capacity and 6.66 kilowatts of panels, but they appear to have disappeared. 

Because the average size of new solar systems has increased, this low limit probably cost retailers too many customers.  Because the average size of solar systems is still rising, this makes me think current size limits may not last long before they either increase or disappear entirely.

Grid Connection Rules

How much solar power you can install depends on the grid connection rules for your location, and these depend on if a property has single or three-phase power.  In South East Queensland, households can usually install…

  • Single-phase:  Up to 10 kilowatts of inverter capacity and 13.33 kilowatts of panel capacity, with a 5 kilowatt export limit.
  • Three-phase:  Up to 30 kilowatts of inverter capacity and 40 kilowatts of panel capacity, with a 15 kilowatt export limit.

I won’t go into export limiting here. However, it can still make sense for a household with single-phase power and a 5 kilowatt export limit to install over 10 kilowatts of solar panels. In comparison, a home with three-phase power and a 15 kilowatt export limit can usually install over 25 kilowatts of panels — more than will fit on most roofs — without export limiting being an issue.

In this article, I’ll assume a household always has enough roof space to fit a system larger than a retailer’s size limit and export limits aren’t considered.  Generally, this will mean the home has three-phase power, but it’s not a necessity.

South East QLD Size Limited Retail Plans

The SolarQuotes Electricity Retailer Comparison tool is great for finding electricity plans likely to provide the most benefit for solar households.  Unfortunately, it doesn’t handle time-of-use or demand tariffs yet, so you may want to use it in conjunction with the government Energy Made Easy site.  But this doesn’t do a good job — or really any job — of showing the best options for solar households.  If you find a plan you think you’d like on Energy Made Easy, I recommend also going to the retailer’s site to see if they offer anything better.

In South East Queensland, I found three retailers offering size limited plans:

AGL:  A size limit of 10 kilowatts of solar panel capacity with a 12 cent solar feed-in tariff.  This was the highest feed-in tariff I could find in the state and is one cent higher than anything offered by a competitor without a solar system size limit.

Discover Energy:  A 10 cent solar feed-in tariff with a limit of 10 kilowatts of inverter capacity and 13.3 kilowatts of solar panel capacity.2.

Momentum Energy:  A 10 cent solar feed-in tariff with a limit of 10 kilowatts of inverter capacity3.

If the goal is to maximize savings on electricity bills, then — at the time of writing — only the AGL plan needs to be considered as there are plans without size limits superior to what Discover and Momentum offer. 

NSW Size Limited Retail Plans

NSW has AGL and Momentum plans with the same size limits and feed-in tariffs as South East Queensland.  AGL’s size-limited feed-in tariff of 12 cents is the highest available and is 0.4 cents higher than the closest, non-sized limited, competing plan.

Finding The Best Solar Plan

Determining the best electricity plan isn’t easy.  With a time-of-use tariff, it can depend on when grid electricity is consumed, and if you’re unfortunate enough to have a demand tariff, then drawing too much grid power just once at the wrong time can cause you to be hit with a hefty demand charge for the whole month.  Daily supply charges also need to be considered.

Finding the best retailer has intentionally been made difficult.  On top of this, plans can change.  In a year’s time, what’s on offer could be quite different. 

I’ll give an example below showing why installing a smaller solar power system to get a one-cent higher feed-in tariff usually isn’t a good idea.  You will have to make your own allowances for the other components of electricity bills other than solar feed-in tariffs.  But these often don’t amount to much.  A half a cent difference in per kilowatt-hour charges for a solar household that consumes 3,000 kilowatt-hours of grid electricity annually comes to a difference of only $15 per year. 

An Example

If you were planning to install an 11 kilowatt solar system but saw you could get a one-cent higher solar feed-in tariff by installing a 10 kilowatt solar power system, would it make sense — all else equal — to go with the smaller system? 

The answer to that is probably not, but some may still decide it’s worthwhile.

To show why it’s not likely to be a good idea, I’ll use the example of a household faced with a choice between installing…

  • A 10 kilowatt solar system for $10,000 that will produce 14,000 kilowatt-hours a year with a 12 cent feed-in tariff.
  • An 11 kilowatt solar system for $10,800 that will produce 15,400 kilowatt-hours a year with an 11 cent feed-in tariff.

Systems in Brisbane of these sizes will generally have no problem providing this much annual output, while in Sydney, it’s possible to obtain this output with north-facing solar panels. 

Larger Solar Systems — Usually — Have A Lower Cost Per Watt

I’ll assume the 10 kilowatt system will cost $10,000.  It is possible to get a well-installed system with reliable hardware for less than this, but paying slightly more can get you higher quality panels, and $10,000 is a nice round figure. 

This comes to $1,000 per kilowatt, but I’ve assumed the 11 kilowatt system will only cost $800 more.  This is because solar systems usually become cheaper per kilowatt the larger they are.  This isn’t always the case.  With some awkward roofs fitting extra solar panels can involve a lot of extra work and increase the cost, but I’ll assume this isn’t a problem for my example home.

All Else Equal

For easy comparison between the two feed-in tariffs, I will assume the following will remain the same whether the home gets a 10 or an 11 kilowatt solar system…

  • The home consumes an average of 14 kilowatt-hours a day from both the grid and solar power.  This is a typical amount for a two-person household.
  • The home pays an average of 24 cents per kilowatt-hour for grid electricity.4

Solar Energy Self Consumption

A home with a 10 kilowatt solar system will typically self consume around 14% of its electricity.  But this percentage will decline with increasing solar system size, so I’ll use 13.5% self-consumption for the larger system.  This will come to:

  • The 10 kilowatt solar system with 14% self-consumption will have 1,960 kilowatt-hours of solar energy self-consumption.
  • The 11 kilowatt solar system with 13.5% self-consumption will have 2,079 kilowatt-hours of solar self-consumption.

Annual Savings

Using the above assumptions, over a year, the amount of savings for each system size will come to:

  • 10 kilowatt solar power system:  $1,915
  • 11 kilowatt solar system:  $1,964

So in this situation, where lower self-consumption is accounted for, and all else is equal, a home will save more per year by installing one extra kilowatt of panels and accepting a 1 cent lower solar feed-in tariff. 

For the household to save less per year with the lower feed-in tariff, the solar system would have to be 10.7 kilowatts or smaller.

Long Term Savings

Just looking at the annual savings overlooks the fact the 11 kilowatt system costs $800 more.  As the household will only be $49 a year better off, it would take over 16 years to pay this extra cost.

But I don’t think that’s the right way to look at it. 

Solar systems can last for decades, but a retailer can change their plans at any time.  While you may have a contract, as soon as it’s over any feed-in tariff advantage from having a smaller system can disappear.  Once it’s gone — all else equal — the household will be $169 worse off each year.  At that rate, it would only take under 5 years for the larger, 11 kilowatt solar system to pay for itself.  

Additionally, having just one solar panel more will make a household a little better off if they do something to increase self-consumption, such as getting a home battery or an electric car. 

But if the one-cent higher solar feed-in tariff did last long term and the example household installed a 12 kilowatt solar system for $11,600, then, with a solar energy self-consumption percentage of 13%, it would come out ahead after 7.4 years.  So a solar system only has to be 2 kilowatts larger to come out ahead within a reasonable period of time with a one-cent lower feed-in tariff.

Cumulative savings - feed-in tariffs

This graph shows the cumulative savings from installing a 10 kilowatt solar system in Brisbane and receiving a 12 cent solar feed-in tariff compared to installing a slightly larger 11 kilowatt solar system and only receiving an 11 cents solar feed-in tariff. I don’t think you can rely on the higher feed-in tariff lasting more than a few years, but if it did last, with a 24 cent grid electricity price, the 11 kilowatt solar system will pull ahead on cumulative savings after 16 years.

My Rule Of Thumb Advice

Because retailers can change their offers at any time, I think there is a good chance size limits will either increase or disappear over the next few years. So my general advice is to install as much solar power as will reasonably fit on your roof.  If you are in South East Queensland and removing a solar panel or two from the system design will give a higher feed-in tariff, then you can roll the dice and hope it lasts long enough for it to be worthwhile.  But unless you are a gambler who is hell-bent on pursuing every possible little advantage, I’d say don’t worry about it.

If offers change and you can get an extra two-cents on your feed-in tariff, your benefit will increase in the short term, but I think it would be even less likely to last long term.  While it’s more worthy of consideration than a one-cent benefit, my advice would still be to not worry about it and just install as much solar power as you can. You’ll be helping the environment more, future-proofing your home and most likely locking in bigger savings over the long term.

Footnotes

  1. Normally connection rules don’t affect your feed-in tariff, but in WA, homes with three-phase power are allowed to install more than 5 kilowatts of inverter capacity but will receive no solar feed-in tariff if they do.
  2. I think it’s likely this limit is actually 13.333 kilowatts of panel capacity.
  3. The terms and conditions for the plan state, “the Electricity Generation Facility must have an installed or name-plate generating capacity of 10 kilowatts or less.”  I contacted Momentum to confirm this meant 10 kilowatts of inverter capacity, and they…  (If this sentence has been left hanging, it means they didn’t get back to me.)
  4. This is slightly higher than what it’s currently necessary to pay in QLD, but I’m expecting electricity prices to increase in July due to a stronger economy.
About Ronald Brakels

Ronald was born more years ago than he can remember. He first became interested in environmental matters when he was four years old after the environment tried to kill him by smashing fist sized hailstones through the roof of his parents’ Toowoomba home. Swearing revenge, he began his lifelong quest to reduce the harm the environment could cause. By the time he was eight, he was already focused on using the power of the sun to stop fossil fuel emissions destabilizing the climate. But it took him about another ten years to focus on it in a way that wasn’t really stupid

Comments

  1. John Finlayson says

    Hi. With self consumption % so low and feed in tariffs meaning high cost of using grid power it appears that household load levelling/load prioritisations is the next step to make self consumption the primary objective with export only secondary.
    Always seems weird that if all house power draws are at same time we immediately import power to cover power requirements (at high cost) and then export for rest of time (low return)
    This is a plc/ controller problem that industry address every day. Is anyone working on this.

  2. christopher lambrecht says

    Notice the article didnt mention victoria, but we are experiencing the same feed in tariff decrease, many only paying goverment minium rate 6.7cents. If you get a little more this seems to be offset by a higher tariff you pay for peak use, or even supply charge, these vary widely, also notice none seem to be giving fixed price commitments for any length of time, five days notice of price change is all thats required. The best thing you can do is self consumption, I had catch diverter installed to divert solar generation to hot water, and is working a treat since last may. I Dont bother with off peak as the gap has closed, 15c vs 22c, works for me.

    • Christopher, make the best of it the feed in tariff in WA is less than half of what you get and drops to zero as Ron mentioned if you have a larger system plus we are limited to 5kW of installed inverter capacity on a single phase connection. How big is your system? I am interested in the Catch diverter but we have little to export in winter with a 5kW system.

      • christopher lambrecht says

        Ian, my system is 9.9 kW of panels 10kW inverter capacity (2x5kW primo inverters) 5kW export limited, had to ditch off peak as catch need to be on same phase, off peak is still there but are not using. My diverter has been installed since may this year and there will be some cloudy days when I use mains power, but have found this system can produce 20kWh in the middle of winter on a clear day. Although cloudy days maybe only 5 to 10 kWh but hot water only needs around 8 kWh for 2 people, the people at catch are very helpful too, cheers.

        • Thanks for that i think I will have to wait until some of the silly restrictions on system size are removed in WA.

  3. Johan Rosman says

    Why is the solar blog always only for the eastern states. The feed in tariff for WA is now 2.8 cents. What impact do larger solar roofs have here. My Tesla is reprogrammed by Western Power to never discharge for own use between 9 am an 4 pm, and the maximum charge and discharge speed is fixed at 4kWh. It feels like North Korea in our state regarding solar. We have a state monopoly with only WP. But as a criticism to your blog: Australia is larger than just the eastern states.

    • Dominic Wild says

      Interesting to read that the Tesla has been crippled by our state monopoly to not discharge for personal use between 9AM and 4PM, great! So you could not charge your electric car with it during clouds.

    • Johan, Do you mean that you cannot use power from your Tesla Powerwall during the day if there is no solar power being produced by your panels or are you referring to exporting to the grid from your battery during the day? Second question you refer to a 4kW charge and discharge limit. Are you referring to exporting power to the grid in this case? Are you on a battery deal with one of the power companies?
      I get that Tesla control charging and discharging rates to maximise battery life but we frequently see 5-7kW spikes (as per the Tesla brochure) if my better half switches on the electric oven and several electric stove elements at the same time. I observe that the Powerwall provides 5kW or a little more and the rest comes from the grid. If the grid is off then I have seen spikes to near 7kW.
      Yes I have noted the 4kW charge rate limit you mention which I see if the battery decides to fully charge due to impending bad weather. Sometimes this happens automatically but mostly I just change the setting to 100% standby for the period of time involved and the battery does its own thing.
      As far as I know you cannot export power from a Powerwall to the grid in WA unless you are on a special deal whereby the grid operator can access your battery as required and these deals are subsidised at purchase.
      I get frustrated about some of the silly regulations in WA such as not permitting larger systems with export controls however if your issues originate in a deal with the devil or his mates that is different.

      • Johan Rosman says

        Hi Ian, thanks for your long post. My tesla was installed in October and I was told Western Power had changed the rules per 1 September. The battery will only charge between 10 am and 4 pm, and can not be used on a cloudy day, even if it is 100% full. Only after 4 pm the Tesla will start to give power to the home. EV’s can not be charged during the day. This to force us to buy dirty power.
        What bites too is the upload/dowload limit that is set at 4 kWh. So I am in the strange situation where the house needs 6 kW, or charge an EV, and only 4 can come out of the battery. This is forced upon Tesla by western Power and WA specific. This limit is not applying to other states and international where 7 kW can be downloaded and uploaded.
        I know I can not export battery power to the grid, but neither do I want to sell for 2.8 cents, what WP sells to my neighbour for 28 cents.
        I had a long talk with western Power. They told me the grid in WA is old and outdated. This is the reason they want to keep fluctuations down to a maximum.
        But the real reason is discouraging the use of green power. We are a state where there is no incentive to go green. All is done to fight us. Even EV’s get some kind of subsidy in eastern states.

        • Johan, live and learn. I must be lucky being an early adopter the current rules as you have explained are certainly stupid not to put too fine a point on it. Just thinking outside the box what happens if you were to drop your main breaker at say 8/9am I wonder if the Powerwall would happily carry your loads and charge if it could? Just thinking.
          I live in the Hills and since installing the battery we have had continuous power in spite of 7 outages the longest being 3 plus hours. During the outages our home became an island and all was well with the battery charging during the day then supplying the A/C during the afternoon prior to the grid supply being restored. Just thinking???

          • Johan Rosman says

            Thanks ian, will definitely try that. One of the main purposes of the Tesla is to supply the house with power between 10 am and 4 pm. But Western Power will not allow that as the battery can not discharge in this time frame.
            The problem of monopoly. If I see the posts from over east with their still good FIT and no restrictions on battery use, I realise what the lack of competition against a state run dirty (coal and gas) energy provider does.

  4. Greg Williams says

    Ronald,
    Even more so nowadays there are numerous “swings and roundabouts” when trying to compare electricity rates (in the examples below, based on ToU).

    e.g.In Northern NSW Origin offers 10c per kWh FIT. However, the fine print reveals this is limited to the first 1250 – 1300 kWh feed-in per billing quarter (i.e. a somewhat miserly limit of 14kWh a day). Once that limit is reached, the FiT is reduced to a miserable 5c per kWh. And bear in mind, Export is generally limited to 5kW in this neck of the woods for a single phase residence.

    At first glance, then AGL appear to be a better deal, with an “unlimited” 12c per kWh FiT. But their Daily Supply Charge is 17.4c dearer than Origin’s.

    So it really does come down to different plans suiting different people depending upon their individual usage and consumption practices.

    All this in an environment where, in less than 12 months, FiT has been reduced by 11 or 12c per kWh and as you point out, is on an almost certain, ongoing downward price and probably quantity-limited trajectory. And there is certainly now no one deal that is best for everyone.

  5. In SE Qld you have the added issue of battery inverters being included in the 10kW/phase inverter size limit.

    This complicates the choice somewhat of what system size to go with if you have any thoughts of adding a battery down the track. Max out with a 10kW inverter PV system and you are in for quite a bit of pain if you then want to add a battery later. Adding an AC coupled battery system then isn’t permitted unless you reduce the size of your PV inverter. So then you need to change over to a hybrid inverter / DC coupled battery and that limits options considerably.

    Worse, you quite possibly will then be in a situation of having solar PV on the roof which is no longer compliant with a system upgrade requiring installation approval. And if you need to work with a different installer for the battery then you are also in warranty purgatory.

  6. Trevor Close says

    I fitted an Enphase system with16 panels in Jan 2017. I had roof space for more but Ausnet insisted that the max feed in was 5Kw and any more than 16 panels at that time was too many as they didn’t trust the feed in limiting ability of the inverters. I objected to no avail as the max output of my inverters was 230vA each, total 3680. 2 years later they relented, so I increased my system to 24 panels which can now at best produce 5Kw. My system has been working perfectly with no problems at all. I’m very pleased with the advice and teaching that I have obtained via Solarquotes. Thank you very much for offering your expertise widely and freely. Well done.

  7. Dominic Wild says

    Just stopped crying reading about 10kW systems or even larger for three-phase. In WA the limit is 6.6kW of panels with a max. feed-in of 5kW and an extremely high feed-in tariff of 3c/kWh! If you go larger, then the feed-in disappears altogether.

    After 3PM, the feed-in tariff goes up to 10c/kWh, whoopey! We pay 26c/kWh in Perth.

    • Johan Rosman says

      Instead of taking that 2.8 cent FIT and them selling is to your neighbour for 10 times the price, you may just as well forego the FIT and build as large capacity as you can.
      I often wonder how these egocentric power plants would cope if all solar roof owners switch their installations off one day at the same time between 12 and 2 and then demand max output by setting all aircons on full.

  8. You have to do all your homework, using existing bills and predicting where prices will go. Then there’s the option of actually asking for a larger feed-in tarriff.
    Yes, I was negotiating with a well-known NSW retailer and the nice chap on the phone offered me 17 cent per kWh feed in instead of their regular 14 cents. No snags, no catches, same contract/limits etc. I also note when reading my contrcat that the 10Kilowatt limit is not mentioned anywhere.

    One more point in favour of buying the biggest system you can fir/afford, is when the weather is not favourable, a larger system will pump out more power than the smaller system.

    • Johan Rosman says

      Thanks Jeff. Once again you show here that competition works. As Western Power has a state owned monopoly we will never get more than 2.8 cent per kWh, after after 3 pm is it is 10 cents (who produces a lot of ebnergy after 3 pm ?).
      Over here, Western Power and Synergy are extremely unpopular totalitarian institutions.

      • David Issko says

        A solid case for going off grid. Send Western Power and Synergy broke!!!! Thankfully, we don’t have such unprofessional, monopolistic stupidity here in Victoria. Just lots of other stupidity.

  9. Michael J Keaney says

    This article touches on the renewable energy elephant in the room, being the lack of, and high cost of storage. Export limits and declining values of feed in tariffs are just a result of this issue.
    Australia has been installing roof top solar at world records rates (helped along by generous government subsidies using money they do not have), with almost no parrallel investment in storage. So now we are in the situation where millions of domestic PV installations generate far more energy than the property consumes, but are still completely reliant on the grid after the sun goes down, often in peak usage periods.
    The obvious solution is for each property to store their excess power for later consumption, (using a dedicated battery or their EV battery), but as we are quickly finding out, the economics of batteries just don’t work unless there are huge reductions in battery prices or huge increases in power prices. With Lithium Carbonate prices trebling in 2021 alone, we may have already seen te low water mark for battery prices.

    • christopher lambrecht says

      Michael, some very good points raised, I would also add that the uptake of solar has helped quell the need for more coal fired power generation, when you see the numbers of new houses constructed just imagine the demand without solar. It would be interesting to know the economics of large scale battery storage being leased out to householders on a KW per month basis as our phone internet companies do.

  10. Ron Fellows says

    I really wanted to use the AGL NSW Solar Savers 12c FIT, especially after they dropped my FIT from 9.5c to 5c at the end of my contract. But I have a 12.6kWh nameplate capacity using micro-inverters and it produces a maximum of 10.1kWh. AGL base Solar Savers on name-plate and so a no-go for me.

    After a year I though 5% panel degradation might get me down to 9.5kWh and would try again with AGL with “some facts”. However, my 370W panels are clipped by the micro-inverters and can still produce 10.1kWh. And probably will for the next 3-5 years.

    We have all this battery talk to store excess energy but I have a three-phase aircon and that becomes a financial challenge to save a small amount of money.

  11. Maurice Wedlake says

    Not too sure whether the following is ‘on topic’ or not, but it might give some people food for thought:
    I have 2 x 5 kW limited inverters, fed by 12 kW of panels on my roof.
    I have a separate system comprising 2 x 250 W panels which feed into a (rough – read ‘cheap’) battery system consisting of 4 x 12 volt (used) truck batteries (48 v) and an inverter which feeds my fridge, fans for a solar air heating system (winter use only) my TV (Which doesn’t get a lot of use) and it powers the washing machine around once a week (only do laundry on sunny days)!!
    The 10 kW system generates on a yearly average around 50 times more energy than I use! (I am a one-person household, and I don’t waste energy)!
    In the light of seemingly ever decreasing FIT’s, what I would like to know is the feasibility of me not claiming a FIT at all, and having the energy that I put into the grid, credited to, say, my children’s accounts (or whoever I would like to nominate) which would effectively give them a pseudo FIT of the full (daytime) electricity costs, probably less some charge, for account management or whatever. Hello not-for-profit retailers!
    I don’t foresee any technical reason why this may not work, but the logistics might be a bit of a nightmare!
    Anyone care to comment? Ronald? Finn?

  12. Leo Hillyer says

    Hi Maurice, good idea. Enjoying all the comments so far.
    I think if you supplied a debit card number etc, to your retailer, you should be able to direct your credit to another bank account, not yours.
    I’m impressed with your ratio of 50 to 1, we thought we were conservative at under 3 Kw per day from the grid on average, with about 30 Kw to the grid each day on average. With our Fit of 16c about to go to 10c or less next month, am looking to install a battery and joining a VPP.

  13. Always interesting reading. We have decided to go with a 10.3kW roof top on our new house. The cost differential to 6.6kW was $2000 and the payback period was slightly higher at 4.2 years vs 4.1years (based on our current house consumption data). I have played around with the sizes etc and can to get a payback period of fewer than 4 years. Moving the electric HWS onto day time hours (propose a timer and also a smaller element to flatten the load but over a longer time, max thermostat setting) is the biggest factor to saving money. We did look at rooftop solar HWS with a booster for cloudy days but it did not pay back as fast as roof top solar.

    I have studied the split of the other household power from night time to day time, and to be honest, this had little effect on the payback. This is in the main due to our current energy bill and the system cost coupled with the low feed in rate of 6.8c.

    We went with the 10kW unit to help save more when we have a pool and EV (propose split charging 7.7kW with roof top and grid power).

    I hope that the energy supplier does not decrease the feed in tariff more, but at least we will save on the grid power (and their have also increased the network access charges to help keep revenue).

    I am going to see how things go before consider HEM system other than look at my circuit breakers for HWS etc be relay controlled.

    I am interested in how others are going about maximising their investment returns. This includes other surplus roof top solar energy storage – other than batteries.

    Cheers

  14. I’m confused why there was no inclusion of the south east queensland “no limit” plans/providers, but instead only included 3 proviers who do impose limits.

    Also doesn’t touch on the retailers offering a decent rate and then after 5kw feed in, stopping it or reducing it even further.


    AGL: A size limit of 10 kilowatts of solar panel capacity with a 12 cent solar feed-in tariff. This was the highest feed-in tariff I could find in the state and is one cent higher than anything offered by a competitor without a solar system size limit.

    Would be really helpful to know which competitor was 1 cent cheaper without a limit, as I’m struggling to find anyone offering 11c.

    Origin was the previous leader with 15c no limit/no size on inverter, but thats not changed with them as well down to 10c for first 14kwh , which isn’t ideal with a 20kw system pending weather it will (after house consumption) still feed 40-65kw back to the grid daily.

    Currently struggling to find a provider to change too with origins latest change and cost/expenditure for batteries I still cant justify.

    • Greg Williams says

      Mario,
      But as mentioned above, AGL’s daily access charge is 17.4c dearer than Origin’s – which would “eat up” the first eight or nine kWh FiT advantage of the former.

      So, again, it really does come down to different plans suiting different people depending upon their individual usage and consumption practices – in other words, a “horses for courses” situation.

    • Ronald Brakels says

      Hi Mario

      If you want to compare retailer plans you can use our Retailer Comparison tool:

      https://www.solarquotes.com.au/energy/

      It allows the comparison of flat tariffs. However, a lot of people will have to consider time-of-use tariffs, which are more complex. The reason why I only mentioned plans with limits is because I didn’t want to article to become dated too quickly by electricity retailers changing what they offer. I wanted the article to be of at least some use to people as long as size limited plans are offered.

  15. christopher lambrecht says

    James from my own situation I found using hot water service to divert that extra power was very good move. My consumption was roughly 50/50 day/night hot water off peak. I installed catch diverter green and kept my 3.6 kw element, this works very well as some days a couple of hours clear sky is all that is needed/available for hot water. Cheers.

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