Costs of solar over time

It was certainly availble, but very few were using it. I’ve always advised people to use system monitoring, to keep an eye on performance and pick up problems early.
You can probably work out some sort of estimate based on your exports and expected output based on your location and PV array orientation, taking into account any shading.

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You can use a spreadsheet to analyse basic data which is reported on your power bill and by your inverter. It won’t give time based usage like that recorded by a smart meter, but can provide information to make decisions.

We used a spreadsheet for many years to track export, import, PV use for each tariff (peak, off peak and shoulder where applicable).

If one isn’t exporting much power (that being the amount exported is less than battery storage capacity and subsequent import usage), batteries are less likely to have much benefit as there will be limited excess generation for the battery storage. One needs to have significant export for battery systems.

It is also worth noting that at this point in time a battery system won’t be an economic proposition. It isn’t known if and when they are likely to be. Battery systems are also not overly reliable at this stage either. Both are covered by other threads in this forum.

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This Choice article is undated so it makes it difficult for readers to interpret where prices may currently be, eg, is the article a few years old so battery prices may now be more affordable, or is it recent so it may still be a few years wait.

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At least January 2020 if not later in the year, based on the link to the tests which are dated.

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Another option for sizing up the costs and relative benefits of a battery.

The calculator does not put a value on the environmental benefits, or increased energy independence. That’s a different decision?

Solar Quotes also has a comparison table with most of the available battery options. The same can be used in conjunction with the guides on the Choice website.

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We have had our system installed since May 2011. We estimated it would take 7 years to recoup the costs. It took eight years. Our inverter, SunnyBoy, has the facility to download generation (Sunny Explorer). I download at the end of each month and so have data from when it was installed. I also have the value of each 3 month generation in dollars and we are currently over $2500 in front of the original cost. Our summer generation really pays for our winter lack of generation. We also get the much higher payback for our input. We believe it has been a very worthwhile investment.

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And these figures only cover $$$. There are other less obvious benefits too - not the least of which is the uptake of domestic PV systems which has dragged power suppliers/market (kicking & screaming) into the 21st century…

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Continuing the discussion from Costs of solar over time:

We installed our first 10 panels Apr 2015. I have kept a spreadsheet record of costs and feedin tariff returns since then. The first panels cost $6,500, they were the top Chinese brand and we had micro inverters (very new tech at the time) installed because we spread the panels across two areas of the house. We were paying 22.74 c per Kwh for power and about $1 daily supply charge. Our costs pre panels around $2200 per year including daily supply charge. I estimate similiar to burdith it would take 7 years to pay off the system. The first 12 months our power costs were reduced 50%, plus feedin return was $40. Estimated pay off time by end of 2017 was 5 years. 2016 power cost rose to 27.74. 2017 Installed another 10 panels, March 2018 installed a battery. Cost of power by 2018 32.22, daily supply now $1.20 per day. Total cost of whole system $24,000.
Savings hard to estimate for these reasons: both retired now so more power used, installed a new all electric kitchen and reverse cycle air con in each room. We use off peak power to top up the battery on days of low solar reducing costs further. On very hot days we turn on more than one air con to keep the house cool and still keep the battery at 100%.
Currently pay approximately $500 per year after feedin plus daily charge $400. Estimate time to pay off total investment will be less than 10 years.

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Interesting reading, our system is seven months old, and cost $5k to install (zero rebates), to date we have harvested $760 from the system, thus I expect our annual recovery to be about $1,100. Payback in 4.5 years.
I am not sure if I am calculating the savings in the same way as other people. I calculate it in two parts:

  • The energy we sold (sold Kwh * feed in tarrif)
  • The energy we generated and consumed ((total generation - energy sold) * what we pay for power)

So taking yesterday as an example, we generated 29.2 kwh, and we fed 15.5 kwh back to the grid.
we currently pay 25.894c/Kwh and get 10.2c /kwh as a Feed In Tarrif.
So our earning from the solar yesterday was (15.5*10.2)+((28.2-15.5)*25.894) = 513c ($5.13).

I know that this ignores the 10% pay on time discount from the energy supplier.

I believe this is the most accurate way to calculate how much your solar system is saving us.

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Welcome to the community @Plendo.

I do the same.

Note:
At the end of each year many of us with Solar PV will still have paid something for our electricity. It’s always much less than we would have paid without solar PV.

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On one occasion since 2017 I’ve paid a bill of just over $30 - only because I withdrew over 1000$ credit that had accumulated at just the wrong time (unusually cloudy for a short while between the withdrawal and end of billing cycle). It’s back into around 500$ credit now - I’m fairly happy with that … system paid for itself in around 2 years …

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26.05 reasons for that to be so good? There’s likely others. Some in the community are just exceptional!

For the rest of us including,
Anyone newly into rooftop solar needs to factor in the latest, not so generous feed in tariffs. Maximising self consumption might provide the best return.

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It’s always best to maximise your self consumption when the FiT is less than the cost per kWh.

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It’s hard to make solar work where we live, trees, roof facing the wrong direction, low feed-in and we’re usually at work when the sun is highest. Instead we got a high quality heat-pump water heater. Saves us a lot and I reckon a payback time of 3-4 years. Stainless steel construction so it should last at least 20 years.

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Well done.

We did that at our previous residence and dramatically slashed our electricity usage and costs for hot water.

Hi @Matmatmat, welcome to the community.

High feed-in tariffs is about making money from solar electricity exported to the grid (there are arguments that this causes increased electricity costs across the board as someone has to pay for the generous feed-in tariffs).

Low feed-in tariffs is about saving money by not having to import/use more expensive electricity from the grid.

In relation to your comment you are at work when the sun is at its highest, this usually means that north facing panels with a low feed in tarrif doesn’t make sense for you. If you consume more energy in the late afternoon when sun is still shining (e.g. set aircon for starting before you arrive home, cooking food, pool pumps etc), then west or north-west facing panels make sense and would assist in saving money from electricity otherwise imported/used from the grid. Likewise if you are a heavy morning user, east or north east facing panels would make sense. If you are both, then different strings of panels facing both easterly and westerly could make sense.

A good solar system designer would be able to assess your power usage, when itnis used and if alternative facing panels provide any long term financial benefit.

If you have trees all around the house shading it for most/all of the day, then solar possibly won’t be a financial option unless you have another place on your property to set up a system (shed in the sun, cleared area for ground mounted system etc).

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While I’m sure Plendo is correct, I’m just simply comparing bills from previous years, with bills since solar.

Mainly because when we installed solar, we took the opportunity to get rid of all gas heating. So there’s no way to make a “correct” comparison, apart from comparing bills.

And yes, we’re on track to get “pay-back” in about 4 years, after also taking into account the reduction in the gas bill.

But coming up in a couple of years is the “big one”. We intend buying an EV, one that is designed purposively to be used as a “house battery” as well. After that our savings will be 2/3rds of the cost of the solar installation.

Tell me one other foolproof way to invest your money for a net after tax return of 66% !!!

Wait - there’s more! We never “spent” money installing solar. We simply exchanged X dollars from “cash at bank” and converted it to X dollars - “home improvements”. And because the panels were subsidised, the value of the increase in home improvements is a lot more than the dollars we took out of the bank, to do it.

And I don’t have to snivel about lumps of coal to justify my existence. We are proudly contributing to the reduction of carbon emissions. Even though we’re elderly and have no children, we CARE.

We care about the environment. We care about the global climate crisis. We care about the animals, birds, insects, reptiles and marine creatures. We care about the Great Barrier Reef. We care about the quality of the air everyone breathes. We care enough about the world that we will be leaving behind, to do whatever we can to leave it in the best possible condition.

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ccmpl, I commend you on your attitude, I find it refreshing to have someone express basically what we all know to be right.

A year ago, we were living in a small rented townhouse with minimal if any insulation, gas heating, cooking, and hot water, our Winter energy bills averages $17.92 a day. We now live in a house we built (yes we did everything that did not require a licence), it is well insulated, all electric, with the most efficient devices we could find (heat pump water heater, heat pump clothes dryer, reverse cycle aircon, etc.) we are also 583 meters higher. Our power bill averages $6.46 last winter. Yes comparing the total cost makes perfect sense, but in our situation it does not tell us how much financial benefit we get from the solar.

Interesting to do the sums on a battery, I don’t think it makes sense yet, but they are not far away.

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They might be further away financially than what battery manufacturers/suppliers/installers indicate. Battery prices haven’t decreased as forecast and they are likely to only become financially viable if grid electricity costs increase substantially. Currently they are only have a financial benefit if one is off grid and is looking to connect to the grid. The costs to connect to the grid, especially for non-urban residences, can be similar to or more than an off grid PV battery system. This is currently where home battery systems make sense.

Looking at new technologies like lithium ion, flow batteries etc, the other issue is reliability. Current testing indicates that there is some work to improve their reliability.

More about home battery systems, including reliability information, are discussed in this thread…

There is also thought that potentially massive grid based storage systems (battery farms, pumped and traditional hydro etc) make more sense financially for the community as a whole than individuals installing their own home batteries. This is due to economies of scale and that it is cheaper per unit of energy installed. These storages are also actively managed rather than set and forget like home battery systems.

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Assume by ‘makes sense’ deliver cheaper household electricity than buying coal and gas generated electricity?

As @phb suggested there are benefits to the grid when battery systems etc are distributed in larger installations. The costs at scale are also less than a home installation.

The battery reliability trials which are in place are useful, and designed to stress test each sample. It would also be useful to have some alternate performance and reliability data from those units that have been sold to Aussie consumers. More than 20,000 small scale systems have been installed with residential users each year.

That’s enough volume to have some confidence that most users have had successful outcomes, and the systems are not inherently unreliable in everyday use.

From a purely economic view point there are many things we do everyday that do not have a financial return, that cost us money. Some of us have our treasured pets, more than one. Many of us think nothing of the expense of feeding, grooming, vet services, toys and time in exchange for feeling good because we get that unconditional love and respect in return. I gather there are also those in the community who get the same feeling from a big fat battery and inverter connected to their solar PV while feeding excess to the grid. It does not always need to pay a cash return to make you feel good. I stroke our PV inverter daily. :rofl: the OSD controls are touch and contact time sensitive. One way to check the system performance as I walk passed it near the front door.

A well sorted home battery reduces PV feedin during the day and reduces the evening peak demand. Both of these outcomes help the NEG run more efficiently, reducing CO2. Importantly the reduction of peak evening demand flattens the duckbill. A further outcome is less peak demand reduces the premium generators receive to service peak loads. It’s the greater earnings from meeting these peaks that is driving investment in large scale battery farms. Most home battery owners get no financial return for doing so, despite the reality they are helping to push down the wholesale cost of power. Hopefully we all benefit at the retail end.

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