Connecting Solar and Batteries to the Energex Network

Two limits, not one

Inverter capacity is how much equipment you are allowed to install. Export limit is how much you are allowed to send back to the grid. You can install more capacity than you can export. The surplus simply goes to your own loads or your battery instead of the network.

Standard (fixed) connections

On a fixed connection, the usual arrangement for residential Energex customers is:

• Single phase: up to 10 kW total inverter capacity, exporting up to 5 kW
• Three phase: up to 10 kW per phase, 30 kW total, exporting up to 5 kW per phase and 15 kW total

Within those numbers the approval process is routine. Above them, the application is assessed individually and the answer depends on your local network conditions.

Dynamic (flexible) connections

A dynamic connection lets your export limit move with network conditions rather than sitting at a fixed cap. In return for that flexibility, Energex allows a larger system. On single phase, a dynamic connection supports up to 20 kVA combined (around 10 kVA of solar plus 10 kVA of battery inverter), where a fixed connection caps you at 10 kVA in total.

For a household that wants both a decent array and a decent battery on single-phase supply, that is often the difference between a system that fits and one that does not, without paying to upgrade to three phase.

The trade-off is that your export is curtailed when the network needs it. There is a floor: even when Energex reduces your export, you are still permitted 1.5 kW. That 1.5 kW is also the emergency backstop the system defaults to if communications drop out.

Voltage rise: the real constraint on long streets

This is the part nobody mentions at the sales stage. To export, your inverter has to push its voltage slightly above grid voltage. If the grid voltage in your street is already high (common at the far end of a long feeder, and common in parts of Brisbane where a lot of solar went in at once), your inverter hits its upper limit and throttles back or trips off entirely.

The symptom is a system that was quoted at a given output and quietly produces less, usually on bright afternoons when everyone else's solar is also exporting. It is not a fault, and replacing the inverter will not fix it.

What does help: an inverter with good voltage-rise behaviour, correctly sized AC cable between inverter and switchboard (undersized cable makes it worse and is a frequent culprit), placing the inverter as close to the board as practical, and adding storage so the surplus goes into a battery instead of fighting the grid. If voltage rise is the constraint, a battery genuinely does more for your yield than more panels would.

Who does the paperwork

We do. Every system we install goes through the Energex connection application, and we handle it as part of the job, including the cases where the answer comes back as a lower export limit than you hoped, which we will tell you about rather than let you discover from your next bill.

Timing

Straightforward residential applications within the standard limits are usually quick. Applications that need individual assessment (larger systems, or areas already carrying a lot of solar) take longer, and the timeline is Energex's rather than ours. We will give you a realistic expectation rather than an optimistic one.