Dynamic export limits, and whether you want one
The case against, first. A dynamic limit means you do not know in advance exactly how much you will be allowed to export at any given moment. A fixed limit is predictable. If certainty matters more to you than average output, fixed is the simpler product.
For most households the dynamic option still comes out ahead, because the average matters more than the worst case.
Fixed and dynamic, side by side
| A fixed limit | A dynamic limit | |
|---|---|---|
| How it is set | Once, conservatively, for the worst conditions the network expects | Moves with what the local network can handle |
| At three in the morning in July | The same as at one in the afternoon in January | Above a fixed cap whenever there is headroom |
| When the network is congested | Unchanged — it already assumes congestion | Comes down, then recovers |
| Your floor under the Code | 10kW default | At least 10kW when export is not being actively controlled |
| What it needs from you | Nothing beyond a standard install | An inverter that can receive a signal, and a working connection to it |
How it works
A fixed export limit is set once, conservatively, for the worst conditions the network expects. It applies at three in the morning in July and at one in the afternoon in January, identically.
A dynamic limit moves. When the local network has headroom, which is most of the time, your allowance sits above what a fixed cap would have been. When the network is congested, it comes down.
Sources: Electricity Authority.
Why a network would prefer this
Export limits exist to manage voltage and reliability on the local low voltage network. Too much export in one place at once pushes local voltage up.
The problem is that a fixed limit solves this bluntly. It restricts everyone, permanently, for a condition that occurs occasionally. A dynamic limit restricts the people causing the constraint, at the time it is happening, and leaves everyone alone the rest of the time. That is better for the network and, on average, better for you.
Take it if offered
Take it if you are installing above 6.6kW, if you have or plan a battery, or if your household exports a lot because the house is empty during the day. The upside scales with how often you would otherwise be hitting the cap.
Stay fixed
Stay fixed if you are installing a small system that will rarely reach 10kW of export anyway. The dynamic option gives you headroom you will not use, in exchange for equipment requirements you would otherwise not have.
We will tell you what your distributor actually offers
Whether a dynamic limit is available to you is a question about your address, not a national answer.
Common questions
General information only. Availability of dynamic export limits, curtailment frequency and equipment requirements vary by distributor and by address, and change without notice. Confirmed in your tailored quote.
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