Solar interconnection is the process through which a utility or distribution-network operator reviews and authorises a grid-connected system. The process checks inverter behaviour, protection, service capacity, local network conditions, metering, and export. It is separate from local building and electrical permits.
A completed installation may remain switched off or non-exporting until the required approval is issued.
Why interconnection exists
Distribution networks were designed to deliver electricity to customers. Rooftop solar can reverse power flow and affect voltage, protection, transformers, conductors, and operating visibility.
Small compliant systems are often straightforward, but the operator still needs accurate records. Higher local solar penetration, multiple inverters, batteries, large single-phase systems, or weak network sections can require closer review.
Interconnection protects workers, neighbours, equipment, and power quality.
Find the correct operator
The company selling electricity is not always the organisation managing the local wires. Identify the utility, distribution network operator, cooperative, municipal provider, or independent network responsible for the property.
The bill, meter identifier, address lookup, or installer can help. Keep the application portal, reference number, and contact.
Switching retail supplier usually does not change the physical network operator.
Application information
A residential application can require owner details, site plan, account and meter identifiers, proposed capacity, panel and inverter models, battery, single-line diagram, protection, export settings, certificates, and installer credentials.
Every existing generator or storage device should be disclosed. Aggregate inverter capacity can matter more than panel DC capacity.
Mismatched model numbers or capacities commonly delay review.
Simplified and studied pathways
Many jurisdictions offer a simplified screen for small, certified systems that meet capacity and technical limits. Passing the screen can lead to quick approval or install-and-notify treatment.
Systems outside that path may undergo engineering study. The operator examines local loading, voltage rise, fault contribution, phase balance, protection, and equipment capability.
The pathway should be identified before ordering non-returnable equipment.
Hosting capacity
Hosting capacity estimates how much distributed generation a network area can accommodate before controls, operating changes, or upgrades are needed. It depends on circuit characteristics, existing resources, load, location, inverter settings, and planning methods.
A hosting-capacity map can guide expectations but is not a reservation or final approval. Values change as new systems connect and networks evolve.
NREL emphasises that hosting capacity is not an absolute physical ceiling; mitigation and upgrades can increase it.
Possible outcomes
The operator may approve the proposal as submitted, approve a lower capacity, require export limitation, request different protection, require three-phase connection, identify reinforcement, or decline the design pending changes.
Ask whether limits apply to inverter capacity, net export, phase, or operating mode. These are not equivalent.
The contract should state who bears redesign, application, and upgrade cost.
Network upgrades
Potential work can include service conductors, meter equipment, transformer, voltage regulation, protection, communications, or broader distribution reinforcement.
Costs and timelines vary widely. A homeowner should receive the scope, contribution, ownership, and schedule in writing before accepting.
Compare a smaller system or flexible export option with paying for upgrades.
Export-limited systems
An export controller can cap power flowing into the network while allowing a larger array to serve household loads or charge a battery. The operator may require certified equipment, fail-safe behaviour, communications, settings, and commissioning evidence.
Export limitation does not guarantee zero curtailment. When production exceeds onsite use, storage charging, and the permitted export, the inverter reduces output.
Read solar export limits and curtailment for the operating consequences.
Batteries and hybrid systems
A battery inverter can export even when the owner intends self-consumption. Hybrid, AC-coupled, backup, grid-charging, and VPP modes should be represented accurately.
Adding storage later can require a new application or amendment. The original solar approval may not leave capacity for another inverter.
Document maximum combined output and control logic.
Local permits remain separate
Planning, building, fire, electrical, and private approvals address the property and installation. Utility interconnection addresses the network boundary.
Completing one does not complete the other. The project schedule should show dependencies and responsible parties.
Use solar permits and inspections alongside this guide.
Inspection, meter, and agreement
The operator may require a passed local inspection, commissioning records, signed agreement, final equipment schedule, and photographs before changing the meter or approving operation.
Metering must record import and export under the local tariff. An inverter's monitoring data is not a substitute for settlement metering.
Keep the connection agreement and permission-to-operate notice.
Changes after approval
Panel additions, inverter replacement, battery installation, altered export settings, phase changes, generator integration, or removal can require notification or approval.
Like-for-like service work should still preserve compliance and records. Do not bypass controls to increase export.
Unauthorised changes can affect safety, tariffs, insurance, and future sale.
Interconnection checklist
- Correct operator identified.
- Existing generation and storage disclosed.
- Final equipment and capacities listed.
- Single-line diagram matches design.
- Simplified or studied path confirmed.
- Fees, studies, and upgrades allocated.
- Export and phase limits understood.
- Local permit dependencies tracked.
- Meter and inspection requirements recorded.
- Final agreement and permission retained.
Solar interconnection is part of system design, not a formality after installation. Resolve the network pathway early enough that approval conditions can shape equipment, capacity, cost, and savings honestly.