How To Get A 25% Bigger Solar System For Virtually Nothing

By Finn Peacock
Chartered Electrical Engineer, ex-CSIRO & Founder of SolarQuotes.com.au

A little-known fact about the "solar rebate" (aka the "Small-Scale Renewable Energy STC Scheme") is that the amount of 'rebate' you get is tied directly to the amount of solar panels you have installed – and only to the panels.

In other words – you don't get a rebate for your inverter, the racking/mounting/wiring, or anything else to do with the complete system – it is just based on number of panels.

Another little-known fact is that, under Clean Energy Council guidelines, you can 'supersize' your system and install 25% more solar panels than your inverter is rated for.

So, if you have a 5kW inverter, you can install 6.6kW worth of panels on the roof – assuming you have enough space on your roof, unlike this guy:

But why would you want to do this?

Because the rebate makes it dirt cheap to add 1.6kW of panels to a 5kW system – if you upsize when you buy. Here's some ballpark figures so you can see what I mean regarding the cost:

Cost of good quality 5kW solar system: $6,000

Cost to add another 1.6kW of panels to this system at time of installation: from $300

How can the extra panels be so cheap? Because the solar rebate goes up with every panel you add and covers the cost to buy those extra panels.

Remember, the installers are on your roof anyway, so the incremental installation costs for those panels are very low.

Don't make the mistake of adding the panels at a later date. Then the installer has to muster the installation crew, and get back on your roof, and the cost of that upgrade will be closer to $1,500 – so nowhere near as cheap.

And don't worry about having more panels than inverter capacity.  Your solar power system will only ever produce its rated capacity on an absolutely ideal day (the middle of summer, when it isn't too hot – because when it gets too hot your panel performance degrades!)

So if you had a 5kW inverter with 6.6kW of panels attached to it – then yes, on a perfect day in the middle of summer, your inverter will be 'clipped' at 5kW output, meaning the extra juice from that extra 1.6kW goes to waste.

But for virtually every other day in the year, when conditions are not ideal, you'll wring more power out of that same system.

This chart demonstrates the concept:

As you can see – there's virtually no difference in performance between a 4.6kW inverter with 6kW of panels, and a 6kW inverter with 6kW of panels.

Won't this blow up my inverter?

No – solar inverters 'pull' power from the panels. The panels do not "push" power onto the inverter.

Meaning that the inverter will only ever take as much as it needs, and never any more.

The next step.

The only criteria for claiming the rebate is that it's installed by a CEC-accredited installer, using panels approved by the CEC, for a total system size of less than 100kW.

To be put in touch with CEC-accredited installers that we have pre-vetted, and know all about maximising your rebate using this technique, simply click the button below: