Grid interconnection is the process of connecting an electrical system to the public electricity network under defined technical and commercial conditions. In EV charging projects, it covers everything required to connect a charging site safely and legally — from the initial application and network studies to construction, protection settings, metering, commissioning, and final authorization to energize.
What Is Grid Interconnection?
Grid interconnection is more than “running a cable to the grid.” It includes:
– Securing the right connection capacity (kW/kVA) for the site’s planned demand
– Ensuring compliance with the network operator’s technical rules at the point of connection (POC)
– Installing and verifying metering, protection, and any required limitation schemes
– Completing documentation and tests required for sign-off and energization
Why Grid Interconnection Matters for EV Charging
Grid interconnection is often the biggest constraint and timeline driver for EV charging rollouts.
– Determines how many chargers can run at once and at what power
– Sets site operating limits that may require dynamic load management
– Drives project schedule through DNO/DSO study and reinforcement lead times
– Protects network stability and reduces grid congestion risk
– Enables future scaling through staged capacity increases or future load reservation
What Grid Interconnection Typically Involves
Application and studies
– Submit a grid connection application with demand profile and design details
– DNO/DSO performs capacity and network impact studies
– Receive a connection offer describing capacity, conditions, costs, and timeline
Construction and installation
– Build connection works: service upgrade, new feeder, transformer, or private substation
– Install internal distribution: switchgear, distribution boards, ducting, protection devices
– Implement metering and measurement points needed for control schemes
Protection, control, and compliance
– Verify earthing arrangement and protection coordination
– Ensure power quality compliance where required (harmonics, flicker, unbalance)
– Implement import/export caps and fail-safe logic if required
Commissioning and energization
– Perform electrical and functional commissioning tests
– Complete grid commissioning at the POC and submit evidence pack
– Obtain final authorization to energize under the interconnection conditions
Grid Interconnection for Import vs Export Sites
The pathway depends on whether the site can export power.
– EV charging sites are typically import-only loads
– Sites with PV, BESS, or V2G become import + export interconnections and may require additional compliance steps and limitation schemes
Common Pitfalls
– Engaging the DNO too late and missing the critical path timeline
– Overestimating diversity/simultaneity, leading to unrealistic demand submissions
– Ignoring internal site bottlenecks even when DNO capacity is available
– Missing documentation and test evidence required for sign-off
– Not planning for expansion (no spare ducts, undersized switchgear footprint)
Related Glossary Terms
Grid connection
Grid connection application
Connection offer
Grid connection agreement
Grid commissioning
Grid capacity
Network reinforcement
Dynamic load management
Distribution Network Operator (DNO)