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Solar System Size Limits: Export Limits Per State (2024)

Feature image for "solar system size limits". The image shows 2 modern houses in suburban Australia, one with more solar panels than the other.

When you first think about putting up solar panels, you may get super excited about putting up a ton everywhere. Totally understandable; we all want to reduce electricity bills, right? But have you ever wondered if there are solar system size limits?

Yes, yes, there are. They’re put up by your local electricity network company, and there’s a reason for it. We’ll get into that and everything you need to know about this topic in this article.

We’ll cover the upper limit capacities, state limitations and good-to-knows, and single-phase power vs. three-phase connection limits. Below is a list of the topics we’ll get into. Feel free to skim or skip.

Why is there a need for solar power system limits?

Very simply, safety and stability. We’ll talk about those, but, very briefly, you need to know that the DNSPs, or Distribution Network Service Providers, are your local electricity retailer. These are the guys that build the poles and wires, and it’s up to them to keep everything running smoothly and safely.

That being said, let’s talk about the safety and stability reasons why there’s a need for solar power system size limits.

Safety

Backfeeding, or whenever surplus energy is sent back to the grid, can occur during outages. This can cause an overload that could potentially lead to unfortunate events, including equipment damage and safety risks to linemen.

If your system size is too large for the power grid, your home could increase the chances of these risks. You don’t want that, and the DNSPs don’t want that. Hence the strict regulations.

Stability

Solar power, by nature, is intermittent. This can cause voltage fluctuations and frequency instability. This can be a problem because the grid’s frequency must constantly remain at 50 Hz.

The voltage and frequency swings could, again, damage equipment and pose safety risks, particularly when unregulated. It’s the DNSP’s job to make sure that doesn’t happen, hence the PV system size limits.

This brings us to our next topic of discussion.

Exactly what are the limits?

This is where the discussion can get a little confusing. Although limits are predetermined, they vary by location because the limits would depend on how robust the local network grid infrastructure is.

Also, sometimes these aren’t exactly “hard” limits; thus, it pays to ask the professionals when you can. The typical recommended system size for a residential home in Australia is 6.6 kW, and the common limit for residential systems is around 5–10 kW.

Before we continue, though, let’s understand two things:

  1. single-phase connection, and
  2. three-phase connections

Single-phase vs. three-phase connections

Simply put, these two are connection types. You can choose how power is delivered from the grid to your home or business.

Single-phase connections are used for most residential homes with low- to mid-energy needs. The more complex 3-phase connections are made for larger homes and businesses that require a lot of power.

Export limits per state

This refers to the maximum amount of excess energy that your system is allowed to send back to the public grid. These are limits set by your local DNSP.

It’s also important to note that these limits generally refer to inverter capacity rather than the solar panels themselves, although some of them do put limits on both. That being said, here are the export limits per state’s DNSP:

1. New South Wales

  • Ausgrid:
    • 10 kW inverter capacity per phase (single phase = 10 kW; 3 phase = 30 kW)
  • Endeavour Energy:
    • Single phase = 5 kW
    • 3 phase = not stated
  • Essential Energy:
    • 3 kW for rural areas
    • 5 kW for urban areas
    • Single- and 3-phase specifics are not stated.

2. Victoria

3. Queensland

  • Energex
    • Single-phase = 10 kW
    • 3 phase = 30 kW
    • 10 kW per phase on dynamic connections, 5 kW per phase on basic connections
  • Ergon
    • Single-phase = 10 kW
    • 3 phase = 30 kW
    • 10 kW per phase on dynamic connections, 5 kW per phase on basic connections

4. Western Australia

  • Horizon Power
    • No specific limits are listed. Their regulations are based on what they call feed-in management, where they have a device that limits the amount of solar energy you can export to the grid.
  • Western Power
    • Single phase = 5 kW
    • 3 phase = 1.5 kW
    • Western power has a lower limit for larger systems to encourage the installation of solar systems only for self-consumption.

5. South Australia

  • SA Power Networks
    • Fixed export limit: 1.5 kW per phase
    • Flexible export limit: up to 10 kW per phase

6. Tasmania

  • TasNetworks
    • 10 kW per phase
    • Single phase = 10 kW
    • 3 phase = 30 kW
    • I got this information from their latest (2024) Basic Micro EG Technical Requirements document. Take note that if you want to see this information from them, you will have to download a PDF.

7. Australian Capital Territory

  • Evo Energy
    • 5 kW per phase
    • Single phase = 5 kW
    • 3 hase = 15 kW

8. Northern Territory

Note that a larger system often requires specific approval from your local network, which may include lengthy technical evaluations. As long as you’re within the limits listed above, though, you can expect automatic approval.

Moreover, these limits can change at any point in time. They’re all accurate as of writing, but make sure to check in with your DNSP or speak with your local solar systems installer.

Now, about those “approvals” we mentioned.

The approval process

The process typically goes like this:

  1. Initial visit/consultation and property/roof space inspection
  2. System size up and designing
  3. Local government intervention (DNSP approval and building permits, if necessary)
  4. Compliance check with
    • AS/NZS 4777
    • AS/NZS 5033
    • other relevant codes
  5. Technical compliance check (inverter and solar system specifications)
  6. Application submission (documentation and review process)
  7. Approval and activation

Note: Homeowners with solar power systems can earn credits (i.e., feed-in tariffs) for excess energy sent back to the grid. This is possible through net metering. Another option is to add a solar battery to further aid this cause.

What is a solar battery, and how does it help me?

A solar battery is exactly as it sounds; it’s a device that stores energy captured from your panels for later use. It helps with your energy needs in many ways.

  1. More electricity is stored for later use. It is super helpful when there are blackouts, low solar turn-out days, or inclement weather.
  2. Increased total capacity. This is more advantageous if you use more power than you can generate. Rather than having to make your system larger, maybe adding a battery would be enough of a solution.
  3. Solar self-consumption. Solar self-consumption is when you use up all the power you’ve generated for yourself. This is the best way to maximize your investment while cutting down on your electricity bill.
  4. Regulatory benefits. Some regions offer rebates and incentives for installing solar batteries. Make sure to speak to your local provider about this!

Conclusion

Wrapping up, I hope this guide has answered all your concerns about your solar system and its potential limits. Just a quick recap, though: these limits are mostly placed on your inverter capacity and how much your rooftop solar can export to the grid.

These limits are decided by your local DNSP for the safety and stability of everyone. However, the more phases you have, the higher your limits typically are. These limits could also change, so make sure to check regularly.

On that note, we have a network of pre-vetted solar installers that are ready to help right away. Just let us know, and we’ll send 3 FREE quotes from them your way.