On September 9, 2024, I paid a lot of money to get solar panels installed on my house. It included a battery. This post serves as a financial breakdown of my solar system after one year, including everything I did to maximise my return on my investment along the way.
The solar system and battery itself is installed in a location in Southern Australia, Adelaide, in its Northern Suburbs. My roof is east/ west facing, and doesn't have complicated topology. Almost all parts of the roof are covered in solar panels, meaning I get good generation throughout the day.
AI image, not my actual house :D
First, the system itself, from my installer's documentation:
Canadian Solar TOPHiKu6 440W * 24 Panels
Fronius Primo GEN24 8.0 Inverter
Tesla Powerwall 2 Battery
For this system, I paid $22,500 AUD, which on the day of payment, would have been equivalent to the following in other currencies:
| Currency | Value |
|---|---|
| USD | 14,985 |
| EUR | 13.500 |
| GBP | 11,200 |
| BTC | ~0.2277 |
Now, there's a great little benefit of the Fronius Solar App. It tells me how much I've saved directly by combining the cost for time of use, export value, which gets me a baseline. The only problematic calculation is that of the battery savings.
This means, that over the lifetime of the system, the combined benefit of energy used from the panels, and energy exported to the grid is valued at:
Now this doesn't include the "value" from the battery - which is only available from the Tesla app, which is frankly, garbage. It won't allow a daily (over the course of a year) export of data, so instead I have averaged battery usage over the year by the month, in KwH, then can figure out how much it saved based on the peak and overnight rate - which is when the battery is used most often - when the sun ain't shining.
Firstly, though, in 366 days, the battery has delivered 2565 KwH to my home, which is pretty good for a 13.5 KwH appliance! That's approximately 190 full charge cycles, though in reality, I do not believe the battery has ever gone completely flat. Given that the warranty claims 70% capacity will still be available after 10 years (or 37000 KwH of use) - I'm only 6% through that in 10% of the warranty period, which means my battery should have higher than 70% usable capacity by the end of the ten year warranty.
Anyway, some rough calculations on what the battery has saved me since installation: about $1019.
Savings Summary
So, that means in a single year:
$1019 (battery savings)
PLUS
$3186.81 (self consumption and exports)
EQUALS
$4205.81 saved
$350 a month I didn't need to pay to power companies. Electricity is EXPENSIVE in Australia.
I've "paid off" 18.6% of the solar system in a single year. But the savings don't end there. I took advantage of several offers by switching electricity companies throughout the year - and joined a "virtual power plant" to get a state government rebate.
Other Incentives
| Rebate | Value |
|---|---|
| State Government Rebate for VPP | $780 |
| Retailer Incentive for VPP | $200 |
| Grocery Gift Card for Joining VPP | $200 |
So there's another $1180 that I got as an advantage from joining (and swapping) power companies throughout the year. The power company I am with at the moment also gives me membership to a local supermarket's loyalty program which gives 10% off a shopping trip a month, up to $50 - so if I spend $550 in a month on groceries, that's up to another $600 of cost offset - but that's not realistic, just another perk of me turning the screws on the energy companies and capitalism however I can. :)
Payoff, After A Year
So that takes the value of the savings from my system to:
$ 4205.81 (Energy costs not incurred)
PLUS
$ 1180.00 (Cash Incentives)
EQUALS
$ 5385.81 Cost Offset
So, taking that into account, in a single year, the solar system has been 23% offset in a single year! I'm dreaming! :)
Some Fun Facts Over the Year:
Total Consumption: 8,832.7037 KwH
Average Daily Consumption: 24 KwH
Total Generation: 15,037 KwH
Average Daily Generation: 41 KwH
Total Energy Sent to the Grid: 6,639 KwH
Average Daily Exports: 18.13 KwH
Days with the highest Production:
| Date DD.MM.YYYY | Production (KwH) |
|---|---|
| 20.12.2024 | 75.54532 |
| 07.12.2024 | 74.74506 |
| 31.12.2024 | 74.73408 |
| 25.12.2024 | 74.52161 |
| 13.01.2025 | 72.95112 |
| 03.01.2025 | 72.89446 |
| 10.01.2025 | 72.64229 |
| 24.12.2024 | 71.55681 |
| 19.12.2024 | 71.5269 |
| 18.01.2025 | 69.90382 |
Days with the lowest Production:
| Date DD.MM.YY | Production (KwH) |
|---|---|
| 25.07.2025 | 4.01092 |
| 25.08.2025 | 6.91468 |
| 07.06.2025 | 8.11552 |
| 09.07.2025 | 8.23401 |
| 14.06.2025 | 8.40225 |
| 04.08.2025 | 9.87222 |
| 09.09.2024 | 11.75145 |
| 29.07.2025 | 13.04234 |
| 05.07.2025 | 13.20226 |
| 06.06.2025 | 13.75931 |
Days with the highest Consumption:
| Date DD.MM.YYYY | Total Consumption (KwH) |
|---|---|
| 27.01.2025 | 71.4330742 |
| 09.03.2025 | 62.5309639 |
| 25.12.2024 | 62.2266083 |
| 04.02.2025 | 60.9784631 |
| 03.02.2025 | 60.0035103 |
| 13.01.2025 | 59.3321175 |
| 02.02.2025 | 58.0100725 |
| 16.12.2024 | 56.5546547 |
| 12.03.2025 | 56.5112094 |
| 10.03.2025 | 53.7663742 |
Days with the lowest Consumption:
| Date DD.MM.YYYY | Total Consumption (KwH) |
|---|---|
| 30.08.2025 | 10.0983375 |
| 09.09.2024 | 11.0464514 |
| 14.06.2025 | 11.3264533 |
| 21.09.2024 | 12.6355739 |
| 12.05.2025 | 12.9461578 |
| 24.09.2024 | 12.9719503 |
| 23.11.2024 | 13.0055639 |
| 05.07.2025 | 13.2402639 |
| 11.05.2025 | 13.2518053 |
| 21.04.2025 | 13.3445697 |
TLDR: If you live in Australia, and don't have solar panels and a battery, and have the roof space, just do it. It is a no brainer. Get a set up that enables you to have electricity when there's a power outage, too - with a battery. In this year, my battery gave me power while there was none in the neighbourhood for a period of three hours.
As power prices increase in the coming years, this set up is going to pay itself off marvelously. It will also ensure that I have power available to my house to keep my food cold, and my house comfortable if there are extended outages, given the delta between my consumption and generation.
I just wish that I could afford another two batteries to store the excess power, and then I think I would be able to be entirely off grid! :) If I had, though, purchased BTC, I would have made a larger profit. I prefer energy sovereignty as a first step. :)