Pacific Gas and Electric : Clean Energy Microgrid Keeps Arcata Airport and U.S. Coast Guard Station Powered Following Humboldt Quake and Winter Storms

By Paul Doherty

The Redwood Coast Airport Microgrid (RCAM) has recently lived up to its description as "a lifeline" for Humboldt County and the North Coast during natural disasters and emergencies.

In the immediate aftermath of the early morning magnitude 6.4 earthquake centered in Ferndale late last year, thousands of customers in the Humboldt area lost power.

However, RCAM did exactly what it was supposed to do. It continued powering its 19 customers, including two critical facilities for the region, the Arcata-Eureka Airport and the adjacent U.S. Coast Guard Air Base.

The fully renewable microgrid automatically and seamlessly disconnected, or "islanded", from the electric grid around 2:30am on Dec. 20, when the powerlines serving the area were de-energized due to the earthquake.

Leveraging the electricity stored in the microgrid's onsite batteries, the system becomes an independent, PG&E-operated grid segment, that in this instance kept the power flowing to the airport and air base for nearly 15 hours, while the power remained off for much of the surrounding community.

"RCAM picked up seamlessly when power went out in the county following the earthquake, and despite the outage occurring at more or less the worst possible hour of the year - just after evening peak battery discharge, the second shortest day of the year and one day before the winter solstice, with bad weather - it ran smoothly for nearly 15 hours," said Marc Marshall, principal engineer at Schatz Energy Research Center.

RCAM keeps power on during powerful winter storms

Subsequently, as a parade of historic winter storms battered California at the end of December and into January, RCAM again proved its value, islanding several times including an eight-hour stretch on Jan. 4, when the area lost power due to the severe weather.

"RCAM is able to respond to a variety of hazards, provide flexibility to system operators, and enhance local resilience. Imagine a future with more solutions like this throughout our most vulnerable communities. RCAM is the model, and PG&E's Community Microgrid Enablement Program is designed to enable that future," said PG&E's Aaron August, vice president, utility partnerships and innovation.

RCAM is California's first 100% renewable energy, front-of-the-meter, multi-customer microgrid.

It was commissioned and put into operation in June 2022.

It was developed and is managed through a first-of-its-kind partnership between the County of Humboldt, PG&E, the Schatz Energy Research Center at Cal Poly Humboldt, Schweitzer Engineering Labs, the Redwood Coast Energy Authority (RCEA), Tesla, Inc., The Energy Authority and TRC.

"RCEA is the local government owner-operator of the microgrid generation system and while we didn't expect such rigorous real-world testing this winter, the system exceeded expectations. During a significant earthquake and multiple major storms, the microgrid reliably delivered power during grid outages so that our regional airport and coast guard could focus on their core missions. RCEA will continue efforts to prepare our region for future challenges and help our essential services to stay online when they are most needed," said Dana Boudreau, Director of Infrastructure Planning and Operations, Redwood Coast Energy Authority.

The clean energy microgrid features a 2.2-megawatt (MW) solar photovoltaic array that is DC-coupled to a 2.3-MW (9 megawatt-hour) battery energy storage system, comprised of three Tesla Megapacks. It also includes a microgrid control system, with protection and isolation devices that interfaces directly with PG&E's distribution control center.

During standard blue-sky operations, RCEA uses the microgrid to generate clean energy for the North Coast and participate in the California Independent System Operator wholesale energy markets, including the day-ahead, real-time, and ancillary services markets.

By storing solar energy during the day and releasing it onto the grid as needed in the evening and during peak demand, the microgrid enables greater utilization of solar, supports grid reliability, and creates an economic model for future microgrids.

During emergencies, when the system "islands" from the broader grid, it becomes an independent, PG&E-operated grid segment, maintaining airport flight service and rescue operations.

Learn more about RCAM here.