Redwood Coast Airport Microgrid
A community driven, front-of-the-meter, multi customer microgrid serving critical facilities
Cal Poly Humboldt Sponsored Programs Foundation
Recipient
Arcata, CA
Recipient Location
2nd
Senate District
2nd
Assembly District
$4,616,349
Amount Spent
Active
Project Status
Project Update
Construction was completed in the fall of 2021. The 300 kW NEM PV array began operating in November 2021 and the 2.3 MVA battery energy storage system with 2.2 MW of DC-coupled solar (wholesale resource) began operating in the CAISO ancillary services and energy markets in December 2021.
Once the system became operational as a CAISO resource in grid-following mode, the islanding functional testing began. All islanding function tests were passed by April of 2022 and the Microgrid Operating Agreement between PG&E and Redwood Coast Energy Authority (RCEA) was fully executed in May 2022, at which time full Permission to Operate in island mode was granted by PG&E.
The system has been operating automatically since that time with good results. The wholesale resource is dispatched automatically as a Hybrid Resource in response to bids and offers placed by RCEA’s scheduling coordinator, The Energy Authority (TEA). Automatic islanding is reliable, generally seamless, and 100% inverter based. PG&E Distribution Control Center operators and engineers have gained confidence with the system, which they can view and control from Rocklin, CA.
When a 6.4 magnitude earthquake struck on December 4, 2022 and knocked out power for all of Humboldt County, the Redwood Coast Airport Microgrid seamlessly islanded and provided 15 hours of backup power to the local commercial airport, the US Coast Guard Air Station, and 17 other customers inside the microgrid. Several other multi-hour islanding events have occurred due to winter storms and the like, with a total of 36 islanding events totaling 58 hours of bulk electric grid outage over a 27-month period. RCEA, PG&E, the Schatz Center, and the microgrid customers are happy with the microgrid performance.
Until recently, there were significant problems with the DC-DC converters that connect the DC-coupled PV array to the battery storage system. However, the defective DC-DC converters have been replaced with a product from a different vendor, and they are now performing as intended. This will allow for the full close-out of the project. The project team recently completed a draft version of the final report. Going forward, the Schatz Center is engaged in replicating the RCAM concept in other communities under PG&E’s Microgrid Incentive Program, which is based on the RCAM project.
The Issue
As load-serving entities, community choice aggregators (CCA) are procuring local community-scale renewable generation and energy storage to serve their customers. IOUs are updating interconnection processes, developing tariff structures, and grappling with the impacts of more distributed intermittent renewable generators on the grid. Meanwhile, climate change has increased the frequency and severity of natural disasters, highlighting the importance of resilient electricity supplies to keep critical facilities operating in times of need. This project demonstrates a replicable model for multi-customer, critical facility community microgrids, including a tariff structure that allows a third-party-owned, grid-forming generator to energize an islanded section of the distribution system operator's grid.
Project Innovation
This project is a community-scale renewable energy microgrid located at the California Redwood Coast-Humboldt County Airport. It is the first multi-customer, front-of-the-meter (FTM) microgrid on PG&E's distribution system. The grid-forming generation resource is owned and operated by a CCA (the Redwood Coast Energy Authority, or RCEA) and is 100% renewable. The microgrid circuit is owned and operated by PG&E. Under the Community Microgrid Enablement Tariff the microgrid is able to provide reliable back-up power services to critical facilities when needed while also participating in the wholesale electricity market and providing renewable energy for the airport during normal "blue sky" operations. Bi-directional EV chargers have also been installed as part of the project and integrated into the microgrid.
Project Goals
Demonstrate a replicable community microgrid that can provide resilience to critical facilities
Provide renewable power to the local community during “blue-sky” conditions
Successfully design, install, and operate the first FTM renewable energy microgrid in California
Develop and implement agreements, procedures, protocols, and tariffs necessary for a FTM community microgrid
Measure the benefits and costs of the microgrid and the distributed energy resources included in the project
Evaluate the business case and assess market opportunities for replication
Report on results and lessons learned for the benefit of utilities, CCAs, and others wishing to install similar systems
Project Benefits
In order to manage increased DERs, California needs sophisticated DER management systems and strategies, and microgrids can play an important role. This project has led to significant technological advancements and breakthroughs by deploying a highly automated, multi-customer microgrid to provide end-use customer resiliency support and wholesale market participation with renewable energy. Reliable islanding has been demonstrated for customers on the circuit. RCEA collaborated with PG&E to create experimental tariffs and agreements for operating multi-customer microgrids, and these tariffs and agreements have become important examples, enabling the development of the Community Microgrid Enablement Program and the Microgrid Incentive Program. These programs provide a pathway for other communities to deploy multi-customer community microgrids to serve critical facilities.
Affordability
Affordability
The solar PV array has lowered annual energy purchases and reduced costs by more than $50,000/year by using onsite renewable energy resources to meet a portion of the onsite load. Directly coupling the battery and photovoltaic array on the direct current bus reduced the cost of required distribution system upgrades. Nonetheless, it is challenging to make community microgrids pay for themselves.
Economic Development
Economic Development
An estimated 3,280 MWh/yr of wholesale renewable electricity generation and the DC-coupled energy storage services are estimated to generate revenues of $390,000/yr. O&M costs are estimated to be $145,000/yr. With an upfront cost of $10.6M, the benefit-cost ratio of the project over an estimated 25 year life is only 0.43. The ratio is increased to 0.6 by an estimated $2.1M resilience benefit, and approaches 1.0 under a 2-week outage scenario.
Environmental Sustainability
Environmental Sustainability
Over 3,280 MWh/yr of renewable electricity will be generated. This is estimated to result in CO2 emission reductions of over 930 MT/yr.
Reliability
Reliability
The microgrid has successfully served the regional airport and U.S. Coast Guard Air Station with reliable, safe, and seamless grid-quality power during 36 regional power outages. The resulting islanding events totaled 58 hours of grid outage over a 27-month period. The resilience benefit was estimated to be $2.1 M over the life of the project.
Equity
Equity
We developed and executed the agreements, procedures, and protocols necessary to deploy and operate a multi-customer, FTM community microgrid. This paved the way for the CPUC’s Multi-Property Microgrid Tariff and Microgrid Incentive Program, which makes this type of project possible for other communities. Key members of the project team are now pursuing similar projects for disadvantaged Tribal communities in northern California.
Key Project Members
Jim Zoellick
Principal Engineer
Schatz Energy Research Center, Cal Poly Humboldt
David Carter
Principal Engineer
Schatz Energy Research Center, Cal Poly Humboldt
Upcoming Events
We do not have any upcoming events. Check back soon for updates!
Past Events
Browse past events to access presentation slides and recordings.
