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Borrego Microgrid

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

CoverageDetailed public record
Named organizations18
System facts32
Sources reviewed13
Evidence reviewed2026-07-20

SDG&E's Borrego Springs community microgrid serves an isolated desert feeder with extensive local solar, batteries, an ultracapacitor, diesel backup, and advanced islanding controls. The original system supported thousands of customers during major 2013 outages. A major Microgrid 3.0 upgrade replaces two 1.8 MW diesels with two 2.5 MW Tier IV Final units and adds six Tesla battery containers totaling 7 MW/14 MWh. Replacement generators were commissioned in March 2025, while June 2025 community minutes say the battery was still commissioning and local/remote control integration remained unfinished. DOE/NREL work nevertheless completed field validation of renewable-led black start and islanding using a grid-forming battery and PXiSE controller.

Research status
Operating community microgrid in a major upgrade/integration phase. The two 2.5 MW replacement diesels were commissioned and functional by March 2025. The 7 MW/14 MWh Tesla BESS was still commissioning on 4 June 2025, with local controls targeted for September and remote integration by year-end; no later official completion confirmation was found through July 2026. A proposed 250 kW, 16-hour hydrogen resource also remains unverified as commissioned.
Historical classification
Community
Reported capacity
4,000 kW
Coordinates
33.25587, -116.37501
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 Borrego Microgrid?

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

Organization

AES

Legacy attribution requiring disambiguation: later technical reports use AES 1, AES 2, and AES 3 as asset identifiers for energy-storage systems, not as evidence that AES Corporation supplied or owned them. [8]

Organization

Anza-Borrego Desert Natural History Association

Community partner for the current upgrade and resilience work. [5]

Organization

Borrego Water District

Community/critical-services partner for the current upgrade. [5]

Organization

California Energy Commission

Public funder and research partner for the original community microgrid and subsequent lessons/upgrade work. [3][5][12]

Organization

Horizon Energy

Original architecture, business-process, and systems-integration participant (identified more fully as Horizon Energy Group in the project review). [10][11]

Organization

IBM

Original RDSI project-management participant. [10][11]

Organization

Lockheed Martin

Original RDSI consortium participant; the located sources do not assign a narrower equipment role. [10][11]

Organization

Motorola

Original network communications and security participant. [10][11]

Organization

National Renewable Energy Laboratory (NREL)

Research and validation partner for controller-in-the-loop, grid-forming BESS, renewable black-start, and islanding tests. [5][7][8]

Organization

Oracle

Original outage-management and distribution-management systems participant. [10][11]

Organization

Parker Hannifin

Integrator/power-conversion partner for the original 500 kW/1.5 MWh Saft battery. [9]

Organization

PXiSE Energy Solutions

Supplier of the later microgrid controller used in the renewable-led black-start and grid-forming-storage work. [8]

Organization

Saft

Manufacturer of the original 500 kW/1.5 MWh battery system. [9]

Organization

SDG&E

Utility owner, operator, lead developer, controls integrator, and interconnection authority for the Borrego Springs community microgrid. [3][5][10]

Organization

Tesla

Supplier identified in community project updates for the six-container, 7 MW/14 MWh upgrade battery system. [6][5]

Organization

U.S. Department of Energy

Funder of the original Renewable and Distributed Systems Integration demonstration and the later Solar Energy Technologies Office renewable-black-start project. [10][5][7]

Organization

UCSD

Legacy catalog attribution not corroborated by the original DOE partner slide; the named academic partner was University of San Diego, not University of California San Diego. [10]

Organization

University of San Diego

Original project participant supporting regulatory-design work. [10][11]

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
700 [1]
KW Gas/Diesel
1800 [1]
Storage
.5/1.5 MW/MWH [1]
Community served
Approximately 2,500 residential and 300 commercial customers on a single radial feeder [3]
Local solar resource
Approximately 26 MW utility-scale PV plus roughly 3 MW customer rooftop PV in the CEC final report; the CPUC later describes the microgrid as supporting about 40 MW of local solar resources [3][4]
Legacy battery fleet
1.5 MW / 4.5 MWh total across AES 1 (0.5 MW/1.5 MWh) and AES 2 (1 MW/3 MWh), equivalent to three hours at aggregate nameplate power [4][8]
Ultracapacitor
Approximately 0.25-0.3 MW with about 30 seconds of support, depending on rounded source description [4][8]
Legacy diesel generation
Two 1.8 MW units, 3.6 MW total [3][4][8]
Replacement diesel generation
Two 2.5 MW Tier IV Final units, 5 MW total; commissioned by March 2025 [5][6]
Microgrid 3.0 battery
Six containers totaling 7 MW / 14 MWh (two-hour duration); still commissioning in June 2025 [5][6]
Planned hydrogen resource
250 kW with 16-hour duration in the CPUC's Microgrid 3.0 plan; no commissioning evidence located [4]
Typical peak load
Approximately 14 MW in the CEC's 2024 lessons report [12]

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

Original battery system

Saft

500 kW/1.5 MWh battery manufactured by Saft and integrated with Parker Hannifin power conversion. [9]

02

Grid-forming battery asset

Model not publicly disclosed

The 1 MW/3 MWh AES 2 storage asset was upgraded for grid-forming operation and used as the island-grid leader in renewable black-start testing. 'AES' is an asset label in the technical paper. [8][7]

03

Microgrid controller

PXiSE Energy Solutions

Coordinates batteries, ultracapacitor, diesel generation, switching, load management, and renewable-led black start in the later control architecture. [8][7]

04

Upgrade battery system

Tesla

Six battery containers totaling 7 MW/14 MWh; installation began in August 2024 and commissioning was ongoing in June 2025. [5][6]

05

Replacement diesel generators

Model not publicly disclosed

Two 2.5 MW Tier IV Final units replacing the original two 1.8 MW machines; commissioned and functional by March 2025. The located sources do not identify the manufacturer/model. [5][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

    • 5-Way Trayer SCADA Switch, SS#1575 [1]

  • Storage

    •Substation Energy Storage (SES) [1]

  • Storage

    • One 500 kW/1500 kWh battery at Borrego Sub [1]

  • Storage

    •Community Energy Storage (CES) [1]

  • Storage

    • Three 25 kW/50 kWh units on circuit 170 [1]

  • Storage

    •Home Energy Storage (HES) [1]

  • Storage

    • Six 4 kW/8 kWh units [1]

  • Generation

    • Two (2) 1.8 MW SDG&E Caterpillar Diesel Generators [1]

  • Operating modes

    The microgrid normally remains grid-connected/dormant while local solar exports. During daytime island operation it can serve the whole community; at night it prioritizes critical loads and can shed noncritical load according to available battery and fuel. [3][5]

  • 2013 outage performance

    After an April 2013 windstorm the microgrid served 1,225 customers for about six hours. During a September 2013 storm that downed 20 poles, it served 1,060 customers for roughly 25 hours. [13]

  • Reliability lessons

    CEC's 2024 review records several successful planned outages but also failed islanding demonstrations caused by controller-communications and frequency-stabilization problems, showing that nameplate capacity alone did not guarantee successful transitions. [12]

  • 2023 failure and recovery

    Community minutes report that both legacy generators failed during a 61-hour planned February 2023 microgrid operation, taking the system out of service. The replacement generators were commissioned by March 2025. [6]

  • Renewable black start

    The DOE/NREL project completed modeling, controller/hardware-in-the-loop work, and field tests in which a grid-forming battery led black start and islanding instead of diesel. Synchrophasor and power-quality measurements verified the fast response, and the DERMS interface was replicated at other SDG&E sites. [7][8]

  • Upgrade schedule evidence

    SDG&E's 2024 fact sheet expected completion in Q2 2025, but 4 June 2025 minutes say batteries were still commissioning, local controls were targeted for September, and remote control-center integration for year-end. The later direct evidence supersedes the forecast. [5][6]

  • Market plan

    The CPUC describes planned CAISO market participation for the upgraded assets; it also says the then-current microgrid did not provide resource adequacy. This is a plan, not verified operating revenue/service. [4]

Provenance

13 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 2021-02-28

  2. [2]
    https://building-microgrid.lbl.gov/borrego-springs

    building-microgrid.lbl.gov · Archived source · captured 2021-02-28

  3. [3]
  4. [4]
    California's Grid Modernization Report 2025, Volume III

    California Public Utilities Commission · Primary source

  5. [5]
    Borrego Springs Microgrid Fact Sheet

    San Diego Gas & Electric · Primary source

  6. [6]
  7. [7]
    100% Renewable Microgrid Controls: Final Technical Report

    U.S. Department of Energy Office of Scientific and Technical Information · Primary source

  8. [8]
  9. [9]
    Energy Storage Activities in the SDG&E Service Territory

    San Diego Gas & Electric / U.S. Department of Energy · Primary source

  10. [10]
    Borrego Springs Microgrid: RDSI Peer Review

    San Diego Gas & Electric / U.S. Department of Energy · Primary source

  11. [11]
    Microgrids: An Assessment of the Value, Opportunities and Barriers to Deployment in New York State

    New York State Energy Research and Development Authority · Secondary research

  12. [12]
    Lessons Learned from Community Microgrids

    California Energy Commission · Primary source

  13. [13]

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