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Asia / Island & remote community

Mara-ro Island Microgrid

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

CoverageDetailed public record
Named organizations10
System facts24
Sources reviewed9
Evidence reviewed2026-07-20

This record is the stand-alone microgrid on Marado (also rendered Mara Island), South Korea's southernmost inhabited island near Jeju; it is not the neighboring Gapado system. A 150 kW photovoltaic plant using 2,010 GE 75 W modules was commissioned in December 2005 for Nam Jeju-gun and operated in parallel with the island diesel plant. Later Korean utility research describes two 75 kW PV blocks, two 600 kWh battery systems, a short-duration 50 kW EDLC device, supervisory controls, and diesel generation. A 2019 engineering study, however, says Marado's PV and battery equipment was not actually operating because surplus-power and operational problems had not been resolved. That paper's proposed 1 MVA medium-voltage DC connection to Gapado was a simulation/design proposal, not evidence of a built inter-island link.

Research status
Historically commissioned, but the last detailed field-status source found reports the PV and 1.2 MWh battery plant inactive and represents Marado as diesel-supplied. No authoritative later source through July 2026 was found confirming that the renewable plant was restored, that the batteries were replaced, or that the proposed Gapado-Marado MVDC cable was built. Treat the original installation as real, its current renewable operating status as unverified, and the MVDC link as proposed only.
Historical classification
Remote
Reported capacity
See component specifications
Coordinates
33.11563, 126.26782
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 Mara-ro Island Microgrid?

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

Organization

AstroKorea

General contractor for the 2005 solar project. [6]

Organization

GE Energy

Supplied the 2,010 GEPV-75W photovoltaic modules used in the 150 kW plant. [6]

Organization

KEPCO Research Institute (KEPRI)

Microgrid EMS research and demonstration organization [5]

Organization

Korea Electric Power Corporation (KEPCO)

Utility and long-term island-PV project collaborator [2][5]

Organization

Korea Electric Power Research Institute (KEPRI)

Documented and developed the island microgrid EMS/control architecture and associated field research. [7][8]

Organization

Korea Institute of Energy Research (KIER)

Research and system-development partner [2]

Organization

Kwangdong Electronic

Installed the photovoltaic equipment. [6]

Organization

Kwangdong Electronic Co., Ltd.

Local solar installer [3]

Organization

Nam Jeju-gun

Local-government customer for the 2005 photovoltaic project. [6]

Organization

Nam Jeju-gun County

Local-government customer for the 150 kW PV project [3]

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 Solar
150 [1]
KW Gas/Diesel
150 [1]
Storage
100 KW BSS [1]
PV array
150 kW; 2,010 GE GEPV-75W modules in the 2005 expansion [3]
Published diesel configuration
Research model: 250 kW; later project material lists 120, 200, and 300 kW sets [4][5]
Published storage configuration
Research model: 50 kW / 600 kWh; later project material reports 1.2 MWh [4][5]
Published load
40 kW minimum, 80 kW average, 120 kW peak [4]
Photovoltaic capacity
150 kW total: 2 x 75 kW arrays; the original installation comprised 2,010 modules rated 75 W each. [6][7][8]
Battery storage
1.2 MWh nominal, arranged as 2 x 600 kWh systems. The 2019 study reports the battery systems were not operating; power and usable-energy ratings were not established in the sources reviewed. [7][8]
Fast-response storage
50 kW for 5 seconds, described by KEPRI as a 250 kJ electric double-layer capacitor (EDLC). [7]
Diesel generation
Published configurations conflict. KEPRI lists four diesel engines across 120, 200, and 300 kW ratings; the 2019 paper's narrative refers to two 150 kW diesels while one analytical case uses 2 x 120 kW. These are preserved as dated study/configuration values rather than merged into one unsupported total. [7][8]
Electrical system and demand
The 2019 study describes a 6.9 kV island system with maximum load of about 240 kW. [8]
Proposed inter-island link
1 MVA medium-voltage DC connection between Gapado and Marado in the 2019 simulation/design study; construction was not demonstrated. [8]

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

PV modules

GE Energy — GEPV-75W

2,010 modules totaling approximately 150 kW. [3]

02

Power management system

Model not publicly disclosed

Coordinates diesel minimum loading and battery dispatch using droop control; commercial EMS model not disclosed in the reviewed material. [4][5]

03

Photovoltaic modules

GE Energy — GEPV-75W

2,010 open-ground modules supplied for the 150 kW plant. [6]

04

Microgrid controls

Korea Electric Power Research Institute (KEPRI)

EMS and gateway architecture interfacing static transfer switches, intelligent electronic devices, power-conversion systems, PV, batteries, diesel generators, and loads. [7]

05

Fast-response storage

Model not publicly disclosed

EDLC rated 50 kW for 5 seconds (250 kJ), used for rapid transient support in the documented architecture. [7]

06

Load-unbalance compensator

Model not publicly disclosed

A three-phase four-leg inverter compensator was developed and tested using Marado operational data; it is research equipment and should not be assumed to have become the permanent production configuration. [9]

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.

  • Identity

    The project is on Marado/Mara Island. Gapado appears in a later proposed interconnection study but is a different island microgrid. [6][8]

  • Timeline

    The PV plant was commissioned in December 2005. KEPRI subsequently documented a fuller PV-battery-diesel EMS configuration, and the 2019 paper evaluated a possible MVDC interconnection. [6][7][8]

  • Operability caveat

    Although the PV and battery assets had been installed, the 2019 authors state that they were not operating because the surplus-power problem and other operational issues had not been resolved. Installed capacity therefore must not be reported as demonstrated current renewable output. [8]

  • Architecture

    The documented microgrid is an isolated diesel system augmented by AC-connected PV, battery power-conversion equipment, fast transient storage, switching/protection, and supervisory control. The proposed MVDC link would have connected it to Gapado, but the paper reports simulations rather than commissioning. [7][8]

  • Evidence gap

    No current operator report, recent generation mix, fuel savings, battery chemistry, replacement history, or post-2019 operating update was found through July 2026. [8]

Provenance

9 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 2020-07-06

  2. [2]
    Renewable Energy on Small Islands — Mara Island

    Forum for Energy and Development · Secondary research

  3. [3]
    GE solar modules used in large Korean solar project

    Renewable Energy World · Secondary research

  4. [4]
    A novel three-phase four-leg inverter based load unbalance compensator for stand-alone microgrid

    International Journal of Electrical Power & Energy Systems · Primary source

  5. [5]
    Microgrid EMS solution in Korea — Mara Island

    KEPCO Research Institute / Microgrid Symposium · Primary source

  6. [6]
    GE Solar Modules Used in Large Korean Solar Project

    Renewable Energy World · Secondary research

  7. [7]
    Microgrid EMS Solution in Korea - Mara Island

    Korea Electric Power Research Institute / Microgrid Symposium · Primary source

  8. [8]
  9. [9]
    A Novel Three-Phase Four-Leg Inverter Based Load Unbalance Compensator for Stand-Alone Microgrid

    International Journal of Electrical Power & Energy Systems · Primary source

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