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Fort Sill

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

CoverageDetailed public record
Named organizations6
System facts25
Sources reviewed11
Evidence reviewed2026-07-20

Fort Sill has two separate microgrid histories that should not be combined. Eaton's 2013 full-scale research microgrid demonstrated seamless islanding with 480 kW of natural-gas generation, a 400 kW/56 kWh lithium-ion battery, 20 kW PV, and a 2.5 kW wind turbine. A much larger installation-resilience project now in federal planning would add 10.3-18 MW of natural-gas reciprocating generation, optional battery storage, controls, and islanding infrastructure, with a separate planned 10-12 MW-class solar plant. The later capacities are not upgrades proven to have been built.

Research status
The Eaton research demonstration successfully operated in 2013, but its current physical status and continued use were not verified. The newer Energy Resilience and Conservation Investment Program project remained pre-solicitation as of a March 16, 2026 virtual industry day: official 2025 market research described a 10.3 MW base natural-gas plant with an option to 18 MW and optional 2 MW/2 MWh battery increments. A March 2025 draft environmental assessment separately evaluated up to 12 MW of PV and 4 MWh of batteries. No reviewed source establishes a construction award, notice to proceed, or commissioning for the new installation-wide system.
Historical classification
Military
Reported capacity
See component specifications
Coordinates
34.67067, -98.38924
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 Fort Sill?

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

Organization

Eaton

Lead developer and integrator of the 2013 research microgrid, including its inverter, static switch, controls, and full-scale test program. [3][4][5]

Organization

Georgia Institute of Technology

Research partner and affiliation of coauthors on the detailed original microgrid design and test paper. [3][2]

Organization

Public Service Company of Oklahoma / American Electric Power

Fort Sill's utility partner for a planned long-term utility-owned solar facility; the Army said PSO would build, own, operate, and maintain the array. [6][7]

Organization

U.S. Army Corps of Engineers, Louisville District

Acquisition organization conducting market research and the 2026 industry day for the new ERCIP Fort Sill microgrid. [10][11]

Organization

U.S. Army Engineer Research and Development Center, Construction Engineering Research Laboratory

Federal sponsor of the original cost-efficient power-storage and microgrid demonstration under contract W9132T-10-C-0018. [3][4]

Organization

US Department of Defence

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

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
20 [1]
KW Wind
2.5 [1]
KW Gas/Diesel
480 [1]
Storage
400 kW, 56 kWh lithium ion (Li-ion) [1]
2013 demonstration natural-gas generation
Two 240 kW generator sets, 480 kW total [3][5]
2013 demonstration battery system
400 kW / 56 kWh lithium-ion battery connected through a 500 kVA inverter [3][4]
2013 demonstration renewable generation
20 kW solar PV and one 2.5 kW wind turbine [3][5]
New ERCIP natural-gas generation under 2025-2026 planning
10.3 MW base plant, with an option to increase total generation to 18 MW using two nominal 9 MW reciprocating internal-combustion-engine generators [10][11]
New ERCIP battery options under 2025 planning
Two separately priced options of 2 MW / 2 MWh each, for up to 4 MW / 4 MWh if both were exercised; the draft environmental assessment described 4-8 containers of 0.5-1 MWh each. These are proposed options, not installed equipment. [10][9]
Planned solar facility
Army announcement: 10.9 MW on 66 acres. PSO's draft RFP allowed 10-14 MW and originally targeted December 31, 2024. The March 2025 environmental review instead evaluates up to 12 MW with approximately 40,005 fixed-tilt panels and up to 28,000 MWh/year. None of these planning figures proves the plant was built. [6][7][9]
New ERCIP resilience objective
Fourteen days of mission-critical energy resilience using on-site natural-gas generation, isolation, and load shedding; estimated procurement range $25 million-$100 million and planned construction duration 720 days in the 2025 sources-sought notice [10]

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

2013 natural-gas generators

Model not publicly disclosed

Two 240 kW generators, each with a commercial isochronous controller. The detailed paper does not identify genset manufacturer or model. [3]

02

2013 battery inverter and storage

Eaton

A 500 kVA inverter coupled to a 400 kW/56 kWh lithium-ion battery provides fast transition support, load following, and import/export control. Cell and pack supplier and model are not disclosed in the reviewed sources. [3][4]

03

2013 static switch

Eaton

A 1,200 A, 480 V static switch isolates the test microgrid from the utility and supports both planned and unplanned islanding. [3]

04

2013 test loads

Model not publicly disclosed

The full-scale test bed included a 360 hp wye-delta-start induction motor, a 200 hp rectifier-fed variable-frequency drive, smaller motors, and lighting loads, deliberately representing highly dynamic and nonlinear conditions. [3]

05

Proposed ERCIP generation and balance of plant

Model not publicly disclosed

The 2025 concept uses natural-gas reciprocating generators with compressed-air starting, paralleling switchgear, transformers, protective relays, a load bank, medium-voltage breakers, SCADA, reclosers, microgrid controls, and a new six-inch gas connection. Vendors and models have not been selected publicly. [10]

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.

  • General

    The microgrid is composed of two natural gas generators, a battery energy storage inverter, renewables, and a static switch. [1]

  • General

    The integration of the energy storage inverter with a commercial isochronous generator control system is described. [1]

  • General

    A comparison of droop control vs. isochronous control is provided, and the benefits of using an existing isochronous generator control system for microgrid applications are described. [1]

  • 2013 transition control

    During an unplanned outage, the inverter immediately carried the islanded load while the natural-gas generators started and synchronized. The controller then shared power among the inverter and gensets; the static switch enabled later resynchronization and reconnection to the utility. [3][4]

  • 2013 communications and control

    Isochronous controllers were attached to each generator, the inverter, and static switch over dual-redundant Ethernet, with a battery-management-system interface. Demonstrated functions included peak shaving, import/export control, voltage and frequency regulation, and intentional and unintentional islanding. [3][4]

  • 2013 motor-starting result

    Starting the 360 hp induction motor produced more than 2,700 A of inrush. Successful islanded starting required both natural-gas generators and inverter support, while the variable-frequency-drive load was throttled to preserve headroom. [3]

  • 2013 storage-design finding

    The ESTCP project reported that a power-optimized storage configuration met IEEE 1547 performance limits and occupied 13% of the volume and cost 33% as much as the energy-optimized alternative evaluated. This is a demonstration design comparison, not a current battery-price benchmark. [4]

  • New ERCIP concept

    The future system is intended to black-start, separate from the PSO grid, shed noncritical loads, coordinate proposed solar and storage, and sustain prioritized facilities. Its primary firm-energy resource is natural gas, making it architecturally and operationally distinct from Eaton's small 2013 research microgrid. [8][10]

  • Phase and status boundary

    The planned 10.9-12 MW solar array, 10.3-18 MW ERCIP generators, and optional 4 MWh storage must not be added to the 2013 demonstration's 480 kW/56 kWh capacities. Through the March 2026 industry day, the newer project remained in acquisition planning rather than documented construction. [5][9][10][11]

Provenance

11 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 2021-04-20

  2. [2]
  3. [3]
    Design of the Fort Sill Microgrid

    Eaton / IEEE · Primary source

  4. [4]
    Cost Efficient Power Storage Solution for Microgrids

    U.S. Department of Defense SERDP-ESTCP · Primary source

  5. [5]
  6. [6]
  7. [7]
    Fort Sill PV Solar Draft Request for Proposals

    Public Service Company of Oklahoma · Primary source

  8. [8]
    FY 2024 Military Construction, Defense-Wide budget justification

    U.S. Department of Defense Comptroller · Primary source

  9. [9]
  10. [10]
    Sources Sought: ERCIP Fort Sill Microgrid

    U.S. General Services Administration / U.S. Army Corps of Engineers · Primary source

  11. [11]
    Virtual Industry Day: ERCIP Fort Sill Microgrid

    U.S. General Services Administration / U.S. Army Corps of Engineers · Primary source

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