Zero Feed-In, or Zero Export, controls PV output to follow on-site demand and limit export to the grid. It does not mean the installation is electrically independent of the grid, and it is not an installation approval in itself.
Metering and control loop
A compatible meter or sensor measures power flow at the connection point. A controller communicates with the inverter to adjust output. Sensor location, current-transformer direction, phase mapping and communication are essential to correct operation.
Response is not instantaneous. Design and commissioning must consider sudden load changes, measurement tolerance and communication failure according to equipment and connection requirements. A configuration screen showing “zero export” does not replace operating tests.
What happens to excess sunlight?
Suppose 8 kW of solar power is available while the site needs 3 kW. Without available battery charging, output is curtailed close to demand according to the configured control strategy. The remaining potential 5 kW is not converted into useful electricity; it is not stored somewhere implicitly.
A battery can absorb some surplus if it has space, sufficient charging power and compatible control. When it is full, curtailment may return. This makes the load profile and controller behaviour important inputs to the production model.
Three different concepts
| Concept | Main function |
|---|---|
| Zero Feed-In | Limits export while connected to the grid |
| Net Billing | Self-consumption and treatment of permitted exports |
| Off-grid | Supply without reliance on the public grid |
Zero export also does not guarantee outage backup. Backup operation requires a separate design covering isolation, loads and protection.
Checks before implementation
Confirm the applicable connection method and documentation with the responsible network operator. Export limitation does not remove electrical safety requirements or the need for application assessment. Historical guidance should not be assumed to apply unchanged to a new scheme.
Our portfolio records a 350 kW industrial installation in Profitis Ilias with Net Metering and Zero Feed-In. That public record does not establish unpublished controller settings or measured transient performance.
See our Net Billing and Zero Feed-In service and HEDNO's official Net Billing information as a starting point for checking your particular installation. Request documented commissioning results and an explanation of behaviour if communication or a sensor fails.
When adding a battery, consult HEDNO's technical storage FAQ. Permitted charging and discharge flows follow the particular connection conditions, not inverter capability alone. Check the Ministry's current framework alongside technical guidance.
Useful commissioning tests
Export limitation relies on measurement at the correct point and communication between the meter and inverter. Ask to test system behaviour when building demand suddenly falls, generation rises or metering communication fails. Expected responses and tolerances must follow the approved technical design, not a generic “zero export” promise.
Also confirm access to monitoring data so that curtailment can be distinguished from a fault. Zero Feed-In is a power-control strategy, not a substitute for a connection study or documentation required by the relevant operator.
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