Kaiser Permanente Commissions Largest Hospital-Based Renewable
- Healthcare Facilities Microgrids News
Marin Holt
- 0
- 6 minutes read
- Largest hospital-based renewable microgrid in the U.S. at Kaiser Permanente Ontario Medical Center
- System includes 2 MW solar, 9 MWh zinc-bromide battery storage, and 1 MW fuel cell
- Provides 10 hours of diesel-free emergency backup power for all critical branch loads
- Funded by $8.35M California Energy Commission grant to Faraday Microgrids
- Solar array produces ~3,300 MWh/year, avoiding 650 metric tons CO2 annually
Kaiser Permanente has commissioned the largest hospital-based renewable energy microgrid in the United States at its Ontario Medical Center in Southern California. The system pairs 2 MW of on-site solar generation with 9 MWh of zinc-bromide battery storage and a 1 MW fuel cell, providing up to 10 hours of emergency backup power without diesel generators. Faraday Microgrids developed the system under an $8.35 million California Energy Commission grant awarded in 2019.
Critical Perspective
The article highlights an $8.35 million grant for a 2 MW solar microgrid. This scale is smaller than the 10 MW solar project at the University of California, San Diego. The 2017 Richmond pilot project by Kaiser Permanente demonstrated limited storage duration. What is the long-term operational cost and reliability of zinc-bromide batteries compared to other storage chemistries in similar hospital settings?
System Architecture
The microgrid uses zinc-bromide flow batteries rather than lithium-ion, eliminating combustion risk in a hospital environment. The non-toxic chemistry also reduces environmental impact across the battery lifecycle from manufacturing through end-of-life disposal. An automated control system manages electricity production, storage, and consumption at the site, charging batteries when grid power is inexpensive and discharging stored energy during peak pricing periods.
During a commercial power outage, the microgrid serves as the primary emergency backup, providing all of the hospital’s critical branch power needs for 10 continuous hours. Existing diesel generators function as secondary backup for extended outages beyond that window. The on-site solar array is expected to produce approximately 3,300 MWh per year, avoiding an estimated 650 metric tons of CO2 emissions annually.
Broader Healthcare Microgrid Trend
The Ontario deployment builds on Kaiser Permanente’s 2017 pilot at its Richmond Medical Center, which featured 250 kW of solar and 1 MWh of storage. Of Kaiser’s 118 sites with solar power, four now include battery storage, with two additional hospitals under construction in San Jose and Sacramento incorporating solar-plus-storage from the outset. The project has directly influenced California’s approach to supplementary emergency power standards for acute care hospitals.
Critical Analysis
The 2 MW solar array and 1 MW fuel cell interconnect via grid-tied inverters, injecting 5th and 7th order current harmonics at the hospital 480 V PCC; the 9 MWh zinc-bromide bidirectional inverter adds harmonic content during charge/discharge transitions. The 3 MW aggregate DER (2 MW solar plus 1 MW fuel cell) reduces feeder peak demand and defers distribution upgrades on the SCE Inland Empire network.
5-Year Projection
By 2031, operational data from facilities like this will become the standard requirement for securing interconnection agreements, as ISOs prioritize proven Solar PV Array profiles.
Why It Matters
Healthcare facilities face increasing grid reliability challenges, particularly in wildfire-prone regions of California. Traditional diesel-only backup systems carry fuel supply risks during extended outages and face tightening emissions regulations. The Ontario microgrid demonstrates that renewable-plus-storage systems can meet hospital-grade reliability requirements while reducing operating costs and carbon emissions, establishing a replicable model for the 6,000-plus hospitals in the United States.
