As solar technology continues to march forward, average solar system sizes increase, and energy demands evolve – many Australians are now looking at ways to increase the capacity of their existing solar system without starting from scratch.
In theory, adding a few extra solar panels to your roof sounds like a simple way to increase your clean energy production. In reality, adding more solar panels can be a bit more complex.
Typically, you have four options when it comes to increasing the size of your system:
- Add more panels but keep your inverter
- Add panels with micro inverters
- Install a second system
- Replace your existing system with a new one
This article looks at some of the most common reasons why homeowners are choosing to expand their systems, how changing incentives and energy use patterns are changing the equation, and the practical considerations that determine whether upgrading your solar setup is worthwhile.
Can you add more panels to an existing solar system?
The simple answer is yes; it is possible to add more solar panels to your existing solar system.
The longer answer to that question is that it depends on your solar system. And, it may not be worth the hassle.
Adding more panels to your solar system is a little more complex than mounting some extra panels on the roof and connecting them to your inverter.
The compatibility of your inverter, the capacity of your existing system, type of solar panels, available roof space, and a whole host of other factors specific to your setup will all determine your options for adding more solar panels.
If you do decide to add more panels to an existing system, two key conditions must be adhered to:
- Must meet current Australian Standards
- Must receive permission from your DNSP
Must meet Australian Standards
If expanding the existing system, not only do the new panels need to meet the current Australian Standards but the existing panels, wiring and inverter must do so to. If the system is more than two years old, it’s likely the configuration will need an overhaul before it passes the current standards.
Grid connection permission
When adding more panels to an existing system, you must be granted permission from your Distribution Network Service Provider (DNSP). They will determine if your planned modifications meet their inverter sizing and export limits.
Add panels with micro inverters
Micro inverters are another way to add more panels to an existing system. Using micro inverters might save you having to upgrade the existing inverter. They are a little more expensive, but they allow each panel to operate independent of another and therefore increase performance.
While it is definitely possible to add more solar panels, you will need to consult with a solar professional to understand what is possible and what is going to make the most sense for your solar system.
Reasons to expand your solar system
Typically solar panels have a long lifespan, but there are many reasons why consumers choose to replace their system with a larger one or increase the size of their existing system.
1. Greater capacity to meet increased energy demands
A decade ago, a 3kW solar system would probably have been enough to power the average Australian household. Today, however, that same system would fall roughly 30% short of meeting typical energy needs.
A 3kW solar system in Sydney generates around 11.7 kWh per day. Whilst this may still be enough for a household with modest daily consumption, it won’t be enough to service the average household.
For most Australian households, energy consumption has grown significantly over the past decade as new technology, larger appliances, and electric vehicle (EV) charging have become part of modern living.
The average Sydney household now uses 16.5 kWh per day, or around 6,000 kWh per year.
Add an electric vehicle, and that figure can climb by another 1,800 kWh annually – a 30 to 50% increase in total household energy usage.
What was once considered an adequate system size is now falling short of the mark in the wake of new technology driving higher energy consumption.
2. Dwindling feed-in tariffs and incentives
Early adopters will know that feed-in tariffs and energy credits aren’t what they used to be.
In the early years of solar, generous tariffs rewarded households for exporting excess energy to the grid. Given peak generation aligned with peak daylight hours, many systems were sized around earning those export credits.
On top of that, many early adopters were constrained by state-level feed-in tariff incentives which restricted expanding their solar system size.
Not only are feed-in tariffs dropping, but things are also starting to move in the opposite direction. With the introduction of the “Sun Tax” and new two-way pricing models in states like NSW and SA, some households are being charged for exporting power back to the grid during peak solar generation hours.
Changes to feed-in tariffs and rebates are encouraging residents with solar to look more seriously at moving towards energy independence with an updated system coupled with battery storage.
3. Adding a battery to your solar system
For many existing solar owners, adding more solar panels to an existing solar system now goes hand in hand with the addition of a solar battery.
In the past, batteries were a ‘nice to have’ for those chasing energy independence. However, for most, battery storage didn’t make a whole lot of sense in the face of generous feed-in-tariff incentives.
But as we mentioned, with export incentives continuing to fall, batteries are now the logical next step. The new Federal Government battery rebate scheme now offers up to $372 per kWh (or around $4,500 for a 13.5 kWh unit).
With generous solar battery incentives on offer and diminishing savings set to be phased out by 2030, many early adopters are now looking to add a battery to their solar system while incentives are at their peak.
Here’s when adding more solar panels makes sense
It doesn’t always make sense to upgrade your system. Here are three points to consider when looking to add more panels:
- 1. You have an oversized inverter
- 2. You have roof space for more panels
- 3. It’s more economical to upgrade
1. You have an oversized inverter
Many homeowners were sold oversized inverters with the promise that they could tack on more solar panels down the line if they needed. If this sounds familiar, then adding solar panels may be fairly straightforward.
Most solar inverters will have either one or two MPPT inputs (Maximum Power Point Trackers) that help maximise how much energy your solar panels can produce.
If your inverter only has one MPPT then you will need to add solar panels that match your existing solar panels. This can be a challenge in itself if you have an older solar system or the manufacturer that you chose has since stopped making these panels.
If your inverter has a second MPPT, adding more solar panels becomes a lot easier since you can connect new strings of panels without affecting the existing setup.
As a general rule, if your current inverter is 5+ years old or if it was not designed for expansion, then it might make sense to go for a new larger or hybrid inverter that can also support battery storage.
2. You have roof space for more panels
If you’ve still got roof space to spare, expanding your solar setup is one of the easiest and most cost-effective upgrades you can make.
Many of the early solar systems were on the smaller side by today’s standards due to higher cost of panels and lower energy consumption. Adding extra panels to your existing system increases your total generation capacity, helps offset more of your usage during the day, and sets you up for future battery storage if you decide to add one down the line.
3. Adding is more economical than upgrading
If your current system is running well – albeit not meeting energy demands, then adding additional panels rather than replacing your entire system.
If your existing solar system is still functioning well and compatible with any future upgrades you have planned – like adding a battery, then it makes sense to use what you already have to reduce waste and cut cost.
On the flip side, if major components like wiring or inverter are nearing end of life, or if your current setup is going to limit your solar production ambitions, then a new system may make more sense in the long run. It’s worth consulting with a solar specialist to understand what is going to make the most sense.
If you don’t meet these criteria, it may be worth considering microinverters, a second system or an entirely new system.
Can you claim rebates when you add more solar panels?
Yes, you can still claim rebates and incentives when adding more solar panels to an existing solar system.
The Federal Government’s Small-scale Renewable Energy Scheme is not limited to new systems. The scheme offers subsidies for households that upgrade their solar system with new panels using an accredited installer.
Just like with new solar installations, upgrades to existing systems must still remain below the 100kW limit and meet Clean Energy Council standards to be eligible for STCs.
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