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Ausnet Grid Energy Storage System

Current status, energy mix, organizations, suppliers, equipment, controls, reported specifications, and project updates—with source-level citations.

CoverageDetailed public record
Named organizations6
System facts23
Sources reviewed7
Evidence reviewed2026-07-20

AusNet's Grid Energy Storage System (GESS) is a portable 1 MW/1 MWh lithium-ion battery and 1 MVA diesel hybrid, originally commissioned at Thomastown Terminal Station in Melbourne for 22 kV network trials. AusNet physically relocated it in 2020 and commissioned it at Mallacoota in 2021 as the Mallacoota Area Grid Storage (MAGS), where it islands the remote township during feeder outages. The original ABB-led system uses Samsung SDI batteries, an ABB PowerStore PCS100 inverter, Microgrid Plus controls, and containerized switchgear/protection.

Research status
Operating at Mallacoota at the latest owner update. MAGS suffered repeated technical issues in 2023 and again in February-May 2025, including waits for Samsung parts, but AusNet reported it back in service on 14 July 2025. It supplied more than 73 hours of backup during outages from September 2024 through April 2025, including a 13-hour-10-minute event on 17 April. No owner update after July 2025 was found by 20 July 2026, so present-day availability beyond that dated statement is not independently established.
Historical classification
Community
Reported capacity
See component specifications
Coordinates
-37.47131, 144.78515
Evidence note: “Every company” cannot be proven from public material alone. This page lists every organization found in the recovered record and reviewed sources, preserves unknown roles, and explicitly marks undisclosed controller or equipment details.
Report missing evidenceResearch methodology

Project delivery

Who was involved in Ausnet Grid Energy Storage System?

6 publicly identified organizations. Where a recovered source named a participant without explaining its work, the role remains explicitly unspecified.

Organization

ABB

Publicly named participant; role not specified in the recovered record [1]

Organization

ABB Australia

Lead party in the original design-and-construction consortium and supplier/integrator of the inverter, controls, protection, and associated grid-integration technology; it also received enhancement work after the trial. [3][4]

Organization

Ausnet

Publicly named participant; role not specified in the recovered record [1]

Organization

AusNet Services

Distribution-network owner, project sponsor, system owner/operator, original trial manager, and developer of the relocation to Mallacoota; AusNet contributed $7.5 million to the Mallacoota project. [2][3][5][6]

Organization

Samsung SDI

Original lithium-ion battery-system supplier in the ABB-led consortium; AusNet's 2023 and 2025 updates identify Samsung as the source of awaited replacement parts. [4][6]

Organization

Victorian Government

Mallacoota installation formed part of the state program to improve energy service in bushfire-prone areas. [5]

System evidence

Energy mix, capacity, and specifications

Values can describe different project phases, generation sources, storage systems, or other components. Source citations are attached to each figure so discrepancies remain visible.

KW Gas/Diesel
1000 [1]
Storage
1MW Lithium Ion [1]
Battery rating
1 MW / 1 MWh lithium-ion, a nominal one-hour system at rated real power; ABB calls it a 1C system with symmetric charge/discharge capability of plus or minus 1 MW. [2][4][5]
Diesel generation
1 MVA backup diesel generator. It extends island duration, recharges low batteries, and supplies the microgrid; the reviewed primary sources do not establish a manufacturer, model, or kW rating. [2][4]
Grid interface
22 kV distribution connection through a 3 MVA transformer and three-breaker SF6 ring-main unit. [4]
Mallacoota endurance example
AusNet said the 1 MWh battery could serve 1,000 average homes for about two hours and the hybrid could supply the town for up to one day with the generator. This load example does not change the battery's nominal 1 MW/1 MWh rating. [5]
Energy sources at Mallacoota
Battery charged from the grid, diesel generator, and customer rooftop solar present on the islanded local network. The system itself has no dedicated utility-scale renewable generator and no verified annual renewable-energy share. [5][6]
Mallacoota project contribution
$7.5 million contributed by AusNet; the reviewed sources do not provide a full final project cost or separate relocation cost. [5]

Controls and hardware

Equipment and controller details

Manufacturer and model are shown only when a source names them. Generic descriptions are not converted into guessed product assignments.

01

Battery system

Samsung SDI

1 MWh, 1C lithium-ion BESS in four self-contained shipping containers with HVAC and fire suppression, capable of plus or minus 1 MW. AusNet's public rating is 1 MWh; no cell model or chemistry subtype is published. [4][3]

02

Power conversion system

ABB — PowerStore 4Q PCS100

IGBT four-quadrant inverter on a 1,000 V DC bus, rated plus or minus 1,372 kVA; operates as a voltage-source synthetic generator and STATCOM-like resource. [4]

03

Microgrid controller

ABB — Microgrid Plus

Monitors power and energy flows, maintains spinning reserve, coordinates generator/battery load sharing, transitions between grid-connected and island modes, and links by RTU to AusNet's control system. [4]

04

Protection relays

ABB — REF630

Three intelligent electronic devices protect and monitor the system; protection groups change automatically as sources enter and leave service. [4]

05

Synchronization controls

ABB — Synchrotact

Sends signals to Microgrid Plus so PowerStore and the generator match the upstream network voltage and frequency for reconnection. [4]

06

Diesel generator

Model not publicly disclosed

Containerized 1 MVA backup generator. The reviewed manufacturer/owner sources do not establish its manufacturer, exact model, or real-power rating. [4]

Technical record

Architecture, performance, and project updates

Concise technical facts, milestones, operating results, and later developments. Dated notes distinguish historical design claims from current evidence.

  • Storage

    1 MW / 1 MWh Lithium Ion for Peak Lopping, Feeder Islanding, Voltage Regulation, and Phase Balancing [1]

  • Original trial

    AusNet initiated the two-year trial in 2013 and had hardware installed at Thomastown by the end of 2014. Tests covered peak lopping, power-factor correction, voltage and harmonic support, phase balance, and islanded transitions. AusNet selected the diesel hybrid because additional diesel endurance cost less than expanding battery capacity. [2][3]

  • Relocation chronology

    AusNet developed the relocation concept in 2017, carried out enhancement and reliability work with ABB, physically moved the GESS from Thomastown to Mallacoota in 2020, began recommissioning that December, and announced the completed Mallacoota installation in 2021. [3][5]

  • Grid-forming operation

    In island mode, PowerStore supplies the feeder and establishes voltage/frequency so the diesel generator can synchronize. Battery and generator then share load; the generator can increase output as battery state of charge falls. Grid-connected services include charging at low demand, peak lopping, reactive-power control, and voltage droop. [4][2]

  • Distributed solar interaction

    Rooftop solar remains connected behind the islanded town load. AusNet warned in September 2023 that high solar export while the MAGS generator was supplying the town could create excess reverse flow and functional issues; operators and an automatic control system adjust power flow accordingly. [6]

  • Reliability upgrades and failures

    Technical failures prevented backup during some 2023 and February-May 2025 outages. AusNet added a local registered electrical contractor, upgraded generator controls, installed automatic switches, and implemented remote start if automatic start failed, which could take up to 30 minutes. Some repairs depended on Samsung parts. [6]

  • Measured outage support

    AusNet's update records more than 73 hours of backup from September 2024 through April 2025 across ten listed events. In April 2025 it supported five transient outages and one sustained outage, with the sustained event lasting 13 hours 10 minutes. [6]

  • Project-name disambiguation

    The original 1 MW/1 MWh Thomastown GESS is now MAGS at Mallacoota. It is not AusNet's separate proposed 300 MW/600 MWh Thomastown BESS, whose planning permit was approved and whose construction was intended to start in late 2026. [3][7]

  • Evidence gap

    No post-July-2025 owner update, current availability factor, annual energy throughput, diesel use, rooftop-solar share, battery degradation/capacity test, or complete replacement history was found through 20 July 2026. [6]

Provenance

7 sources

Primary owner, government, university, supplier, and engineering sources are preferred. Archived references preserve claims whose original pages moved or disappeared.

  1. [1]
    Recovered Microgrid Projects record

    Internet Archive · Archived source · captured 2021-02-26

  2. [2]
  3. [3]
    AusNet Services Demand Management Innovation Allowance Annual Report 2020

    AusNet Services via Australian Energy Regulator · Primary source

  4. [4]
  5. [5]
  6. [6]
  7. [7]
    Thomastown Battery Energy Storage System

    AusNet Services · Primary source

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