The Photovoltaic and Battery Energy Storage Class System

Power and Water’s Photovoltaic (PV) and Battery Energy Storage (BES) System Specification divides systems into four classes. This applies to systems of all sizes and both residential and commercial customers.

We require all solar and battery energy storage system installers to hold current Northern Territory electrical licenses, as well as current design and installation accreditation and endorsements with the Clean Energy Council. Accredited installers must only install approved CEC equipment.

PV and BES system class type comparison summary

PV inverter size limit1 
ClassApplicantsEligibilityDarwin regionAlice Springs, Katherine and Tennant CreekBES inverter size limit1BES inverter maximum charge rate from the network2Site export limitNominal ramp periodAssessment response timelineAssessment fee
1Residential, small commercialPre-approved

≤ 5kVA single phase OR ≤ 7kVA three phase

< 10kVA single phase OR < 30kVA three phase

< 1kVA single phase OR < 3kVA three phase

< 5kVA single phase OR < 7kVA three phase

PV inverter ramp up in no less 16.67% of nominal inverter output per minute.3N/A
Pre-approved
2

< 10kVA single phase OR ≤ 30kVA three phase

Zero export only
3Medium commercialRequires assessment≤ 200kVA three phase≤ 100kVA three phaseAs determined by assessment6 weeks

$1,306.604

4Large commercial>200kVA three phase>100kVA three phaseBy negotiation

1 1 hour continuous inverter output (AC) rating in kVA. Sum of all inverters must not to exceed limit.

2 Rate of charge from the network must have a variable set point commencing at 1kVA to allow for future changes in this specification.

3 Refer to Clause 6.3.5.2 AS/NZS4777.2

4 Includes GST. Applicable for the 2019-2020 financial year. Fees are subject to change, refer to the Acceptance of Charge form.

PV and BES system class types

Class 1 systems are pre-approved and open to any applicant.

Note: Pre-approval does not apply to remote customers.

Class LimitsSized by inverter AC rating (kVA), per lot in all regions.
PV inverter size limit<5kVA for single phase or <7kVA for three phase.
BES inverter size limit<10kVA for single phase or <30kVA for three phase.
BES inverter maximum charge rateMaximum charge rate (from the Power and Water network) must not exceed 1kVA for single phase or 3kVA for three phase.
Eligibility Open to any applicant.
Site export limit5kVA for single phase or 7kVA (total) for three phase.
Engineering assessment Not required, pre-approved.
Power factor requirements Power factor at site must be > 0.9 at all times.
Timeline Six weeks total for application processing and meter upgrade.
Technical requirementsAS/NZS 4777 series and Technical Requirements for Grid Connection of Photovoltaic Systems via Inverters.


For forms and agreements see the Connections page

Class 2 systems are pre-approved and open to any applicant provided zero-export is achieved at all times.

Note: Pre-approval does not apply to remote customers.

Class limitsSized by inverter AC rating (kVA), per lot in all regions.
PV inverter size limit<10kVA for single phase or <30kVA for three phase.
BES inverter size limit<10kVA for single phase or <30kVA for three phase.
BES inverter maximum charge rateMaximum charge rate (from Power and Water network) must not exceed 1kVA for single phase or 3kVA for three phase.
Eligibility Open to any applicant.
Site export limitZero-Export Limiter Device required.
Engineering assessment Not required, pre-approved.
Power factor requirements Power factor at site must be > 0.9 at all times.
Timeline Six weeks total for application processing and meter upgrade.
Technical requirementsAS/NZS 4777 series and Technical Requirements for Grid Connection of Photovoltaic Systems via Inverters.

For forms and agreements see the Connections page

Class 3 systems are available to three-phase commercial customers only.

An engineering assessment is required for all applications and an engineering assessment fee is required to be paid upon application. This class may be an exporting or non-exporting connection, pending engineering assessment and customer requests/requirements.

You must have approval from Power and Water prior to commencing any installation works.

Class limits

Sized by Inverter Bank AC rating (kVA), per lot.

Maximum inverter bank size
  • <200 kVA Darwin region.
  • <100 kVA Alice Springs, Katherine and Tennant Creek regions.
BES inverter size limitTo be determined by assessment.
BES inverter maximum charge rateTo be determined by assessment.
Eligibility Restricted to three phase customers on a commercial tariff.
Export limits Export or zero-export permitted pending engineering assessment
Engineering assessment Required.
Engineering assessment fee Refer to Class 3 PV Assessment in the Acceptance of Charges form.
Power factor requirements Power factor at site must be > 0.9 at all times.
Timeline Six weeks for engineering assessment, plus six weeks total for application processing and meter upgrade.
Required documentation

To commence the assessment, you or your installer must submit:

  • Completed and signed Class 3 Application Form
  • Payment of the Class 3 assessment fee
  • Technical data and wiring diagram, including:
    • Metering
    • Zero-export device (as applicable)
    • Grid protection relay
    • Circuit breakers/switches
    • Inverter(s)
    • PV array(s)
    • Earthing equipment
    • Distribution circuits
    • Protection, synchronisation and tripping or interlocks.

Following approval being issued, you or your installer must submit:

  • Completed and signed Embedded Generation User Agreement: Formal Instrument of Agreement. Available pending engineering assessment.
  • Payment of applicable meter fee. Refer to the Acceptance of Charges form.

Your solar installer must submit to the Connections Officer, Power Networks, Power and Water Corporation:

Technical requirementsAS/NZS 4777 series and Technical Requirements for Grid Connection of Photovoltaic Systems via Inverters and other technical requirements that are applicable following our assessment.

Class 4 systems are available to three phase commercial customers only.

An engineering assessment is required for all applications. Due to size of systems in this class a more detailed engineering assessment will be required on a quoted basis. Outcomes of the engineering assessment may include increased protection and control requirements, including ramping control.

You must have approval from Power and Water prior to commencing any installation works.

EligibilityRestricted to three phase customers on a commercial tariff.
Export limitsExport or zero-export permitted pending engineering assessment.
Engineering assessmentRequired.
Engineering assessment feeQuoted basis.
Power factor requirementsPower factor at site must be > 0.9 at all times.
TimelineQuoted basis.

Required Documentation

To commence the assessment, you or your installer must submit:

  • Completed Class 4 application form. Please email the Network Development and Planning team for the form.
  • Payment of the quoted engineering assessment fee.
  • Technical data and wiring diagram, including:
    • Metering
    • Zero-export device (as applicable)
    • Grid protection relay
    • Circuit breakers/switches
    • Inverter(s)
    • PV array(s)
    • Earthing equipment
    • Distribution circuits
    • Protection, synchronisation and tripping or interlocks.

Following approval being issued, you or your installer must submit:

  • Completed and signed Embedded Generation User Agreement: Formal Instrument of Agreement. Available pending engineering assessment.
  • Payment of applicable meter fee. Refer to the Acceptance of Charges form.

Your solar installer must submit to the Connections Officer, Power Networks, Power and Water Corporation:

Technical requirementsAS/NZS 4777 series and Technical Requirements for Grid Connection of Photovoltaic Systems via Inverters and other technical requirements that are applicable following our assessment.

Zero-export limiting devices

A zero-export limiter is a device that is used to ensure that PV and BES systems generates as much power as the user requires onsite but not excess energy.

Utilities around the world encourage the use of these devices as they reduce adverse impacts within the local distribution network while still allowing users to significantly offset their consumption.

list of zero-export limiting devices, approved from a technical standpoint as being capable of achieving zero-export by Power and Water is available.

Please ensure that any device on the list that offers protective functions can be set to match protection requirements for inverters as specified in Technical Requirements for Grid Connection of Photovoltaic Systems via Inverters.

If you have a zero-export limiter device that is not approved by Power and Water, Power Networks Engineering will review the device. Please complete the Zero-Export Limiter Device Approval form and send to the Network Development and Planning team.

The following list contains devices from a technical perspective that are capable of achieving zero-export for PV and BES systems. Some of these devices offer protection functions similar to the internal protection found within a CEC approved inverter.

It is the responsibility of the PV and BES system designer to ensure that the protection functions provided by the zero-export limiter are capable of meeting Power and Water's protection setpoints as detailed in Technical Requirements for Grid Connection of Photovoltaic Systems via Inverters.

  • Devices capable of achieving Zero-Export:
  • ABB inverters with compatible meter
  • BCJ Controls Grid Protect
  • ComAp InteliMains
  • ComAp InteliPro
  • Crisp Power and Control – Zero Export Solar System
  • EBA Grid Control Unit GCU-30C
  • Enphase Envoy S-Metered + DRM
  • Fronius – Datamanager with Fronius Smart Meter
  • GNT Engineering ZED series
  • HLP Controls PE200
  • HLP Controls PE200-SILG
  • HLP Controls PE200-Z
  • Integrelec SPS01303-ABB Feed in limiter
  • Integrelec SPS01330-ABB Feed in limiter
  • Integrelec SPS023150-ABB Feed in limiter
  • Magellan Solar Gate
  • PM Control - SolarTune
  • Power & Drive Renewable Solutions Non Export Unit
  • S4Solar Zero Export Controller
  • Schneider Electric Modicon M241 (limited inverter compatibility)
  • Selectronic SP PRO/SP PRO GO series
  • SMA Solar Technology – Cluster Controller with SMA Energy Meter
  • SMA Solar Technology – Data Manager M with compatible energy meter
  • SMA Solar Technology – Sunny Home Manager 1.0 with SMA Energy Meter
  • SMA Solar Technology – Sunny Home Manager 2.0
  • Sol Distribution Sol-0-X Grid Export Limiting System for SMA Inverters
  • Solar Log 1200 PM+
  • SolarEdge Feed-in Limitation
  • Solarmatrix Compact Level 1
  • Solarmatrix LOF
  • SolaX Power Hybrid Series
  • Voltlogic VLI105P1
  • Zero Export Controls Australia CEC3000
  • Zeus Appollo Anti Reverse Current Box (limited inverter compatibility)
  • Zeus Appollo Z21 Hybrid Series

Last updated 14 December 2018.