Grid export control is the set of measures used to limit and manage the amount of electricity a site can export to the grid. It is most relevant for sites that include distributed energy resources (DER) such as solar PV, battery energy storage (BESS), CHP, or V2G systems. Export control ensures the site complies with DNO/DSO connection agreements and protects the local network from overloads, voltage rise, and instability.
What Is Grid Export?
Grid export occurs when a site produces more electricity than it consumes and the surplus flows through the meter to the distribution network.
– PV generation exceeds building + EV charging load
– A BESS discharges to the grid
– A V2G-capable EV exports power through bidirectional charging
Export can be continuous, scheduled, or event-based, depending on the control strategy and market participation.
Why Grid Export Control Matters
Export constraints are increasingly common in congested networks.
– Prevents exceeding export limits in the grid connection agreement
– Avoids voltage rise issues and thermal overload of feeders/transformers
– Enables more DER to be installed behind a limited export connection
– Reduces risk of forced disconnection and non-compliance penalties
– Improves predictability for grid planning and site operation
How Grid Export Control Works
Export control typically measures power at the point of connection (POC) and applies control actions to stay within an export cap.
– Measure real-time import/export with a meter or CTs at the POC
– Compare actual export to the permitted limit (kW)
– Adjust controllable assets to reduce exports when approaching the cap
– Log events and maintain fail-safe behavior if communications fail
Common Export Control Methods
– PV curtailment: reduce inverter output when export approaches the limit
– BESS charging: absorb surplus by charging the battery instead of exporting
– Load increase: increase controllable loads such as EV charging to consume surplus
– Export limiting relays/controllers: enforce hard caps via control hardware and software
– Dynamic export limitation: adjust export continuously based on real-time conditions
Export Control and EV Charging
EV charging can act as a controllable load that helps reduce export.
– Increase charging power during PV peaks to raise self-consumption
– Coordinate charging schedules with solar generation windows
– Use EMS/CPMS integration so EV charging absorbs surplus while staying within site import limits
This is common in green charging hubs and commercial sites with PV canopies.
Key Design Considerations
– Measurement must be at the correct point (true POC exchange with grid)
– Controller response time must be fast enough to prevent export spikes
– Define priority rules: charge EVs vs charge battery vs curtail PV
– Ensure fail-safe default behavior (safe export limit if controller fails)
– Provide documentation and test evidence for DNO/DSO acceptance
– Consider power quality requirements (power factor, harmonics) in inverter settings
Common Pitfalls
– Measuring export behind some loads, causing hidden export spikes at the meter
– Relying only on PV curtailment and missing value from EV load/BESS absorption
– Slow control loops leading to brief export exceedances and non-compliance
– Poor coordination between multiple controllers causing oscillations
– Not documenting export control settings and test results for commissioning
Related Glossary Terms
Dynamic export limitation
Point of connection (POC)
Grid connection agreement
Distributed energy resources (DER)
Battery energy storage system (BESS)
Energy management system (EMS)
Self-consumption
Vehicle-to-grid (V2G)