Quick answer
An approved constraint on net active power exported at a specified grid connection boundary, with site-specific limits, control response and fallback requirements.
Answer: Grid export limitation caps the net active power a site may send into the electricity network under its connection conditions. Export is generation remaining after site consumption and other relevant flows, measured at the specified connection boundary. The limit may be fixed or vary over time. Its approved value, units, phase treatment, response requirements and fallback behavior must be checked for the actual site.
Grid export means power leaving the site
A solar array’s generation is not the same as grid export. In a simple PV-only AC power balance, 8 kW of generation serving 3 kW of site load leaves 5 kW available to export. If the approved export cap is 2 kW, that operating point requires 3 kW less surplus through approved generation control, additional consumption or available battery charging.
A kW limit constrains power. The energy exported over an interval is measured in kWh. Neither the annual generation estimate nor the inverter’s nameplate rating tells you how much energy will be constrained throughout the year.
Reasons for export restrictions can include network loading, voltage and protection constraints. Do not infer a connection offer from a generic hosting-capacity map or assume every household receives the same allowance.
Record the actual connection conditions
| Item | What to confirm |
|---|---|
| Boundary | Which point and equipment measure net site export |
| Limit | Approved active-power value and whether it varies with time |
| Phase treatment | Site aggregate or individual phase restrictions, as applicable |
| Other generation | How existing PV, batteries and other sources are included |
| Response | Approved control response and treatment of brief excursions |
| Fallback | Required behavior if measurements, communications or commands fail |
| Equipment | Exact compatible meter, controller, inverter models, firmware and configuration |
A zero-export connection does not mean no grid imports, and a battery does not make export control unnecessary. A full battery or one at its charge-power limit may be unable to absorb further surplus. A grid-parallel non-export arrangement can still require connection approval.
Fixed and flexible limits: a current local example
SA Power Networks’ Flexible Exports guidance illustrates why limits must be site-specific. As checked on September 30, 2026, its page describes fixed export between 0 and 1.5 kW per phase depending on network area, and flexible limits with a location-dependent lower bound of 0 or 1.5 kW and an upper bound up to 10 kW per phase. Available exports also depend on network capacity, installed equipment and internet connectivity.
These are that operator’s described options, not worldwide residential limits or a promise of continuous 10 kW export. Confirm the site’s application outcome, current connection agreement and equipment requirements before designing or selling the system.
How the limit is enforced
An approved arrangement measures net power at the specified boundary and controls compatible generation or storage to meet the required limit. Measurement location, sign convention, communications, response and failure behavior matter. See export limiting for the control workflow and self-consumption boundaries.
A documented manufacturer example is the SMA Data Manager M EDMM-20 zero-export function. SMA describes active control at the interconnection point and conditions support for third-party inverters on SunSpec Modbus connectivity and function support. This is a specific product scope, not evidence that any inverter or controller can enforce an approved limit.
Installation and commissioning belong with qualified personnel following the applicable manufacturer and operator procedures. Retain the approved setpoint, configuration, metering arrangement and test evidence; review changes to existing generation or storage before treating the previous approval as sufficient.
Calculate constrained energy with time and power units
For a simplified interval model at one AC boundary, assume no battery discharge or other generation. Let available PV power be P, site load L, permitted export X and actual feasible battery charging B, all in kW:
Curtailed power = max(0, P − L − X − B)
Multiply each interval’s curtailed power by its duration in hours and sum to calculate kWh. B is charge power at the same boundary, limited by the actual battery state and equipment; it is not stored-energy headroom in kWh. Avoid subtracting that surplus twice in the dispatch model.
Using the 8 kW PV, 3 kW load and 2 kW cap example over a constant 15-minute interval:
- With no charging, curtailed power is 3 kW, or 0.75 kWh over 0.25 hours.
- With feasible 2 kW charging, curtailed power is 1 kW, or 0.25 kWh. Charging consumes 0.50 kWh at the assumed AC boundary, before accounting for storage losses.
These are hypothetical interval calculations, not annual losses or a control response test. Use matching time-series generation, load, limit and dispatch assumptions for an annual comparison. Coarse averages can conceal variations; there is no universal interval resolution or percentage correction that proves actual compliance.
Questions about export limits
How many kW can I export?
Use the approved site connection conditions. The answer can depend on network location, phase arrangement, equipment and a changing export command; inverter capacity alone is insufficient.
Can I install more PV than the export cap?
Possibly, subject to the operator’s approved system and equipment limits. An export cap is different from a generation-capacity allowance. Compare the additional useful energy and cost before selecting a larger array.
Will a battery eliminate curtailment?
Not necessarily. Charge power, available capacity, losses, operating policy and timing limit what it can absorb. Compare feasible storage and load-shifting scenarios rather than promising full recovery or a fixed payback improvement.
Does an export limit set the export payment rate?
No. Connection conditions govern permitted flows; the applicable tariff or contract governs compensation. Confirm both when estimating financial value, including the possibility that export has little or no value at particular times.
Related Glossary Terms
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