SolarQuotes TV Ep. 4 – Why Bigger Solar Power Systems Are Better

In another jam-packed episode of SQ TV, discover why the 6.6kW system is dead and why you should be filling your roof with solar panels.

We also meet Mike the mechanic who is using a big solar installation to get zero bills – plus $17,000 in feed in tariff revenue over the last 12 months.  Finn visits what was Adelaide’s largest residential solar system in 2003 and finds out how it’s faring in 2021 after nearly 18 years without an inspection.

Also learn about clever gadgets designed to help you make the most from a big solar power system, and much more!

The 6.6kW System Is Dead

0:31 – From what Finn is seeing in the solar industry, everything is about going big – now and into the future. So, how does this reconcile with claims the output of solar power systems need to be limited to avoid “traffic jams” on the grid? Finn explains this is only happening at very specific times and the approach needed going forward – including changing the mindset regarding “wasted energy”.

17-Year-Old Solar Power System Gets A Checkup

3:28 – Back in 2003, this 3.48 kilowatt system in Adelaide – the largest residential installation in the city at the time – cost more than $28,000. Today, a similar sized solar power system costs around $4,000 – and you can get a good quality 6.6kW system for not much more. Finn calls in Pat from Adelaide Solar Repairs to give this old system a long-overdue inspection to see how it’s faring.

Humans Of Solar: Mike The Mechanic

8:34 – Michael from Volv of Adelaide installed a 71kW solar power system  the roof of his workshop – and it turned out to be a very wise decision.

“Solar has been good for me as I have no power bills, and I have an income stream from what is being exported to the grid,” says Michael.

It’s a significant amount of revenue in addition to those zero power bills – around $17,500 over the last 12 months. His outlay – around $80k.

Michael also chats about the future of his work given the shift to electric vehicles.

On a related note, learn more about commercial solar in Australia – these days it’s not so much a question of whether businesses with suitable rooftop should install solar panels, but more why they haven’t done so yet.

Ask Finn: Remote Inverter Shutdowns

11:13 – Mia from Adelaide questions why her solar power system was briefly shut down by SA Power Networks in an incident on March 14 this year. Mia was of the understanding that only systems installed after October 2020 could be remotely shut down temporarily under certain circumstances. Mia also says the system’s Tesla Powerwall battery system didn’t kick in to supply power to the home. Finn explains what happened.

Ask Finn: How Inverters “Throttle” Solar Panel Output

12:48 – Russ asks where the excess solar energy goes when systems are forced to limit their output. Finn describes the inverter magic that happens.

Ask Finn: Solar And Sliced Bread

13:41 – Bee says big solar is the best thing since sliced bread. That being the case, what was better than sliced bread before solar power? Prepare yourself to groan after hearing Finn’s answer.

Installer Profile – Testar Energy Solutions

14:01 – Sam and Aidan chat about their installation business – Melbourne-based Testar Energy Solutions. The pair struck out on their own after being in the industry for some time and seeing some things they didn’t agree with.

“And it was time to do things the way we saw they needed to be delivered,” says Aidan.

They show us around an impressive residential 24kW installation Testar Energy Solutions performed that also involved a Tesla Powerwall install.

 Solar Tech – Catch PV Diverter And Solar Relay

17:29 – With big solar panel systems the way forward and feed-in tariffs not so generous, the name of the game is self-consumption. Finn discusses two gadgets that solar owners can use to help make the most of their systems; the Catch PV Diverter and Catch Solar Relay.

Ronald’s Wrap – Fill ‘Er Up (Your Rooftop)

20:03 – Ronald’s advice is to put as many solar panels on your rooftop as you possibly can – and explains why export limiting isn’t such a bad thing as it enables installing a system larger than you may otherwise be able to. Even if export limits are in place, the amount of energy you may lose isn’t as much as you may think.

‘Finn”ally – Really, Really Big Solar

24:59 – There’s big solar and then there’s Sun Cable’s proposed Australia-ASEAN Power Link project in the Northern Territory. It aims to provide copious quantities of clean energy not only for Australia,  but also Singapore and other ASEAN markets via an undersea transmission system thousands of kilometres long.

About Michael Bloch

Michael caught the solar power bug after purchasing components to cobble together a small off-grid PV system in 2008. He's been reporting on Australian and international solar energy news ever since.


  1. Wolfgang EDDIGEHAUSEN says

    Hi Michael
    The larger, the better is fine and I could add 20kW inverter capacity to my existing 10kW at any time (am 3-phase in Ausgrid area), but…………..
    …………..which retailer would take my energy and pay me for it? I am currently with AGL and they clearly limit me to 10kW, thus me having an undersized system. Any idea how to resolve this?

  2. I spent an hour or two on your web site last weekend during which I concluded that it was pointless installing a system bigger than 6.6kW. My home has single phase power which according to my reading of your advice meant that it was unlikely that I could install an inverter larger than 5kW. Has something changed to make it possible to install a larger inverter these days? By the way, my roof is partly shaded (lots of trees) so I am considering micro inverters.

    • As Ronald and I discussed – in many parts of Australia, despite the 5kW per phase limit, you can install a 10 kW inverter with up to 13.3 kW of panels and export limit the inverter to 5 kW.

      You can see the rules for your local network here:


      • Sascha Bihrenbrodt says

        Hi Finn, I’m still trying to get my head around this. As far as I’m aware, in WA, you won’t get a feed in tariff if your inverter is above 5kW. If you decide to install a 10kW system, not only is it more expensive with a longer pay off period, you lose the feed in tariff if my understanding is correct.

        Why would I choose to go bigger in this situation, if it is possible? It wasn’t really clear in the video.

  3. Wolfgang says

    Hi Finn

    I used this calculator for a 30kW system and it suggest AGL being the best. But when looking into the conditions of AGL it shows the condition that the system must not be larger than 10kW.

    There definitely is a gap for all those exceeding 10kW. No retailer wants them as they make no money then.


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