Why am I still exporting while I have set my PV system to zero-export?

When you configure a PV system for zero-export, you might still see small export values in monitoring data. This often raises concerns, especially when export is contractually restricted or financially undesirable.
This article explains why short export peaks can still occur, how export data should be interpreted, and why this behaviour is technically unavoidable even when the system is configured correctly.

How zero-export works in Autarco systems

Autarco inverters support export limitation (PELD) when a compatible external smart meter is connected. This functionality is available on all inverter models that support smart metering.

A full overview of supported smart meters per inverter series is available here:
Common issues when installing a smart meter (Autarco Help Center)

Zero-export works by continuously measuring grid import and export via the smart meter, sending this measurement to the inverter, and adjusting the inverter output accordingly. Although this process runs continuously, it is not instantaneous.

Why short export peaks can still appear

Even when export is configured to 0 W, it is technically impossible to guarantee zero export at all times. Rapid changes in PV production, such as passing clouds, sudden load changes on-site, measurement and communication delays, and inverter reaction time all play a role.

The total response delay is made up of the meter measurement interval, the communication delay, the inverter reaction time, and the physical reduction of PV power. As a result, very short export events, often lasting only a few seconds, can occur. This behaviour is not unique to Autarco systems and is generally accepted by grid operators, who usually allow short-duration, low-power export.

Why export peaks may look larger in monitoring

In monitoring platforms such as myAutarco, export peaks can appear more significant than they are in reality. Data is reported in fixed intervals, for example every five minutes. A short export event of just a few seconds may therefore be displayed as a full interval, creating the impression of prolonged export.

In addition, export energy is currently calculated as the sum of all phases. Import on one phase and export on another are both counted, which can lead to an overestimation of total export. Improvements are in progress to display phase-averaged export data more accurately.

Internal PELD versus external PELD

Using an external PELD device does not reduce export more effectively than the internal PELD. Both internal and external PELD use the same metering principle and have equivalent reaction delays. External PELDs are mainly intended for multi-inverter installations, not for higher precision. In terms of export limitation performance, both behave the same.

Using a negative export setpoint

In some installations, a negative export limit is configured to create a buffer against short export events. While this can reduce measured export, it deliberately curtails PV production and results in permanent energy yield loss.

This approach should only be considered in edge cases, such as installations with very large and frequent load switching or extremely strict grid operator requirements. In most situations, the loss of PV yield outweighs the financial impact of minimal export.

What grid operators actually measure

Export fees are based on official consumption meter data, not on monitoring platform estimates. In practice, the actual exported energy is usually much lower than monitoring data suggests. Monitoring values may look alarming but do not reflect billing reality.

Autarco is actively working on improving export data transparency to reduce confusion for end-users.