Renewable front-of-the-meter microgrid strengthens California’s grid reliability

California’s first 100% renewable energy, front-of-the-meter, multi-customer microgrid is now fully operational, providing enhanced energy resilience for the California Redwood Coast-Humboldt County Airport and US Coast Guard Air Station.

The Redwood Coast Airport Microgrid (RCAM) features a 2.2MW solar PV array that is DC-coupled to a 2MW (9MWh) battery energy storage system, comprised of three Tesla Megapacks.

The new microgrid was developed through a partnership between the County of Humboldt, Pacific Gas and Electric Company (PG&E), the Schatz Energy Research Center at California State Polytechnic University (Cal Poly Humboldt), Schweitzer Engineering Labs, the Redwood Coast Energy Authority, Tesla, Inc., The Energy Authority and TRC.

The RCAM includes a microgrid control system, with protection and isolation devices that interfaces directly with PG&E’s distribution control centre.

RCAM applications

The microgrid serves multiple functions and is managed in collaboration between project partners. Schatz Energy Research Center is the prime contractor and technology integrator, leading the design, testing and deployment of the clean energy microgrid.

“With its successful deployment and the development of new microgrid agreements and tariffs, RCAM has become a role model and beacon to communities across the state who are striving to green their energy supply and bolster their resilience in the face of climate change,” stated Peter Lehman, Founding Director of the Schatz Center and project lead.

During standard blue-sky operations, RCAM generates clean energy for the North Coast and participates in the California Independent System Operator (CAISO) 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, it also aims to enable greater utilisation of solar energy and support grid reliability.

PG&E owns, operates and maintains the microgrid circuit and controls the microgrid during “islanded” operation.

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In the event of a broader grid outage, the clean-energy microgrid provides indefinite power for the 19 connected customers by disconnecting or “islanding” from the broader grid when needed and becoming an independent, PG&E-operated grid segment.

This ensures that airport flight service and rescue operations continue without interruption.

Jason Glickman, PG&E’s executive vice president, engineering, planning and strategy, stated: “Thanks to this team’s smart work, microgrids now play a key role in PG&E’s ongoing efforts to harden our electrical system and enhance local grid resilience throughout Northern and Central California.

“We know how much our customers and communities need reliable energy, and this system not only increases local reliability, it also serves as the foundation for a replicable and scalable model for widely deploying multi-customer microgrids across PG&E’s service area. This gives communities a new tool in securing their resilience and clean energy goals.”

Microgrid R&D

Research and development for the microgrid was supported through California’s Electric Program Investment Charge (EPIC).

EPIC is a state-wide, customer-funded programme that enables PG&E, other California investor-owned utilities and the California Energy Commission to demonstrate emerging technology and deploy projects that address grid needs.

The programme aims to help drive the innovation needed to meet California’s policy and clean energy goals while also ensuring the safe, reliable and affordable operation of the grid.

The collaboration between RCAM project partners has informed other technical and policy initiatives, including the development of the Community Microgrid Enablement Tariff and PG&E’s Community Microgrid Enablement Program (CMEP).

Additionally, PG&E along with Southern California Edison and San Diego Gas and Electric, are developing the Microgrid Incentive Program (MIP), aiming to develop clean energy microgrids. The companies anticipate launching this program in late 2022.

The Schatz Center is partnering with several tribes in Northern California to support their clean energy, resilience and climate response efforts, while Cal Poly Humboldt has recently begun design of a renewable energy microgrid to support campus resilience through clean generation.

This microgrid will also be part of the university’s sustainability framework, and will enable students in engineering, environmental sciences, and other programs to gain hands-on experience with innovative climate-friendly technologies.