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Sendai Microgrid

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

CoverageDetailed public record
Named organizations7
System facts24
Sources reviewed8
Evidence reviewed2026-07-20

The Sendai Microgrid was NEDO's 2004–2008 Microgrid Power Quality Supply System demonstration at Tohoku Fukushi University, designed and built by NTT Facilities. It is often misidentified as a Tohoku University project. The system combined two 350 kW city-gas engines, 50 kWp of PV, a 200 kW molten-carbonate fuel cell in the original configuration, and a fast power-quality supply backed by a 600 Ah VRLA battery. NTT Facilities continued managing it after the NEDO demonstration. During the March 11, 2011 earthquake, the external grid failure and voltage collapse initially stopped the engines; the battery/PV-backed highest-quality circuits continued until protective shutdown early the next morning. Operators then improvised provisional wiring, restarted the gas engines, and restored selected hospital and care-facility loads before the utility grid returned on March 14. This was a major resilience success, but not uninterrupted service to every load. Fuji Electric donated a 100 kW PAFC after the disaster, explaining why later descriptions differ from the original fuel-cell inventory. No authoritative asset-specific operating update after the early 2010s was located, so current operation and equipment condition are unverified.

Research status
Historically operational and proven during the 2011 disaster; NTT Facilities continued operation after the 2008 demonstration, but present-day operating status and retained equipment could not be verified from an authoritative post-2013 source.
Historical classification
CHP
Reported capacity
950 kW
Coordinates
38.25383, 140.87407
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 Sendai Microgrid?

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

Organization

Fuji Electric

Donor and manufacturer of the post-earthquake 100 kW phosphoric-acid fuel cell [7]

Organization

NEDO

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

Organization

New Energy and Industrial Technology Development Organization (NEDO)

Sponsor of the 2004–2008 Microgrid Power Quality Supply System demonstration [6]

Organization

NTT Facilities

System designer, builder, demonstration participant, and post-demonstration manager [6]

Organization

Sendai City Gas Bureau

Supplier of city gas through a medium-pressure pipeline that remained available after the earthquake [6]

Organization

Tohoku Electric Power

External grid utility [6]

Organization

Tohoku Fukushi University

Host campus; its hospital and elderly-care facilities were critical loads [6]

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
50 [1]
KW Gas/Diesel
700 [1]
KW Fuel Cell
200 [1]
Dispatchable generation
Two 350 kW city-gas engine generators, 700 kW total [6]
Solar generation
50 kWp photovoltaic array [6]
Fuel-cell chronology
The original demonstration used a 200 kW molten-carbonate fuel cell. Fuji Electric supplied a 100 kW FP-100i phosphoric-acid fuel cell in July 2011 after the earthquake; sources that simply list a 200 kW PAFC conflate different phases [6][7]
Power-quality storage
600 Ah valve-regulated lead-acid battery behind a 200 kVA Integrated Power Supply, with a 420 V DC bus [6]
Distribution architecture
6.6 kV AC microgrid bus plus A-class 400 V three-phase, B1-class 200 V three-phase, and 300 V two-wire DC services; DC converters were rated 10 kW per unit in a two-active-plus-one-spare arrangement [6]
Illustrated normal load
Approximately 700 kW total in the NEDO schematic, including about 180 kW A-class, 20 kW B1-class, 18 kW DC, and 130 kW B3-class load; the remainder included conventional C-class service [6]
Designed transfer performance
No interruption for DC and A-class service and less than 15 ms for B1/B3/C-class transfers under designed conditions [6]

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

Gas reciprocating generation

Model not publicly disclosed

Two 350 kW gas engine generators connected to the 6.6 kV microgrid bus; manufacturer/model not disclosed in the cited NEDO report [6]

02

Photovoltaics

Model not publicly disclosed

50 kWp array coupled to the system through the high-quality power architecture; module and inverter models not disclosed [6]

03

Original fuel cell

Model not publicly disclosed

200 kW molten-carbonate fuel cell used in the demonstration-era configuration [6]

04

Replacement/donated fuel cell

Fuji Electric — FP-100i

100 kW phosphoric-acid fuel-cell package supplied in July 2011 for electricity and heat at the elderly-care facility [7]

05

Fast power-quality supply

Model not publicly disclosed

200 kVA IPS with a 600 Ah VRLA battery feeding the 420 V DC link and high-priority circuits [6]

06

Thermal recovery

Model not publicly disclosed

Post-demonstration CHP modifications recovered engine heat for space heating, hot water, and chilled water through absorption chillers [6]

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.

  • Management

    The Sendei Microgrid has different categories of loads based on based on the quality of power they require. [1]

  • Management

    It can supply various classes of power quality within the microgrid, seen below. [1]

  • Generation

    The Sendai Microgrid has several generation sources: two gas engines, a phosphoric acid fuel cell (PAFC)1 and a photovoltaic array. [1]

  • Site identity

    The host was Tohoku Fukushi University in Sendai. Tohoku University is a different institution and should not be attached to this asset record. [6]

  • Earthquake sequence

    On March 11, 2011, loss of the Tohoku grid and a voltage collapse stopped the gas engines and ordinary B3/C supply. The IPS battery plus PV supported DC/A/B1 loads until protective shutdown at about 02:06 on March 12. Operators installed provisional cabling and restarted the engines around noon, restoring selected A/B1/C loads; ventilators on B3 were bypass-fed that afternoon. Grid service returned at 08:16 on March 14. [6]

  • Fuel resilience

    Sendai's medium-pressure city-gas network remained available because it was supplied by both LNG and a pipeline from Niigata. The distribution route mattered as much as the nominal generator fuel. [6]

  • Resilience interpretation

    The event demonstrated prolonged local supply to life-safety functions, but it also exposed control-power and restart dependencies. Claims that the whole campus ran without interruption omit the overnight battery depletion and manual reconfiguration. [6][8]

  • Data gap

    The latest authoritative asset-specific material located describes the early post-disaster period. It does not establish that the original engines, batteries, fuel cells, or multi-quality circuits remain in service in 2026. [6][7]

Provenance

8 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 2021-01-20

  2. [2]
    microgridprojects.com

    microgridprojects.com · Archived source · captured 2021-01-20

  3. [3]
    microgridprojects.com

    microgridprojects.com · Archived source · captured 2021-01-20

  4. [4]
    microgridprojects.com

    microgridprojects.com · Archived source · captured 2021-01-20

  5. [5]
    Sendei Microgrid Case Study

    nedo.go.jp · Archived source · captured 2021-01-20

  6. [6]
  7. [7]
  8. [8]
    A Microgrid That Wouldn't Quit

    IEEE Spectrum · Secondary research

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