Large energy projects and programs are tricky by nature to create, and particularly challenging for small, rural communities. The secret to making big things happen is to work with partners and plan ahead.

RCEA’s first collaborative, multi-partner microgrid is living up to its expectations as earthquakes, severe weather, and power outages continue to challenge Humboldt County’s electrical grid.

The Redwood Coast Airport Microgrid is a locally-owned, renewable energy facility at our regional airport. It serves as a modern cornerstone for a healthier, more resilient, and energy-independent community. Projects like this are possible because our Community Choice Energy (CCE) customers support RCEA’s mission to invest our energy dollars locally rather than exporting them to distant shareholders. As each passing season demonstrates what we can expect from climate change, Humboldt shows how to be part of the solution and grow stronger in the process.

The microgrid highlights:

• 300 kW net metered system to offset daily electricity usage at the airport
• 2.2 megawatt solar photovoltaic array feeds wholesale electricity directly into the grid
• 2.2 MW battery storage system providing 9 MWh of energy, composed of three Tesla Megapacks
• Began operation December 22, 2022.
• 7 acres of land leased from the County of Humboldt using a novel approach to deliver renewable energy in lieu of a lease fee.
• Microgrid controller provides the ability to “island” from the main grid so the airport and adjacent Coast Guard facility can run fully on solar and batteries during regional power outages
• Electric vehicle charging stations capable of demand response
• Community Choice Energy dollars invested locally instead of exporting to distant shareholders
• A $5 million grant from the California Energy Commission’s California’s Electric Program Investment Charge (EPIC Program), a statewide program which invests in scientific and technological research to accelerate the transformation of the electricity sector to meet the state’s energy and climate goals
• Funding via RCEA’s CCE Program, supported by a first-in-kind $6 million loan from the USDA
• Partners, vendors and contractors include the County of Humboldt, California Energy Commission, Schatz Energy Research Center, RCEA, PG&E, SEL, Tesla, The Energy Authority, and TRC.

Why a microgrid at the airport?

Although the ACV airport is known for fog, it is actually a logical place for the planned solar array for a number of reasons.

1. Available land: Airports have available land that cannot be developed for other uses, but can be used for solar energy generation. Many other airports have chosen to place solar panels on their property, including the Sacramento, Denver, and Pittsburgh airports. Solar panels are designed to absorb light, and the array will be properly positioned and treated with a special coating to minimize glare and ensure pilot safety, in compliance with Federal Aviation Administration requirements.
2. Decent solar insolation: Despite its gloomy reputation, the ACV site has higher annual sun exposure than anywhere in Germany, where solar is widely and successfully used.
3. Resiliency benefits: The airport and adjacent U.S. Coast Guard Station Humboldt Bay provide critical emergency functions that can be maintained by the microgrid during a power outage or grid shutoff. The Coast Guard Station provides search and rescue for 250 miles of rugged rural coastline, from the Mendocino-Sonoma County line to the California-Oregon border.

In June 2022, local and state leaders, organizations, partners, and the public commemorated the successful commercial operation of a collaborative and innovative project in Humboldt County – California’s first 100% renewable energy, front-of-the-meter, multi-customer microgrid. The Redwood Coast Airport Microgrid (RCAM) was designed to provide energy resilience for the regional airport and U.S. Coast Guard Air Station during power outages, and electricity to the RCEA’s customers while the electric grid is operating normally.

No one could have expected such rigorous real-world testing of the system so soon, but on December 20, a 6.4 magnitude earthquake knocked out power to more than 70,000 electric customers in Humboldt County and the microgrid automatically and seamlessly disconnected or “islanded” from the electric grid as planned.

“The Redwood Coast Airport Microgrid performed flawlessly during and after Humboldt County’s strong 6.4 temblor last December,” said Peter Lehman, Founding Director of the Schatz Energy Research Center. “Operating through a worst case of difficult conditions—the winter solstice, rainy weather, a partially discharged battery—the microgrid seamlessly provided power to the airport and the Coast Guard Air Station, keeping one of the County’s lifelines up and running for nearly 15 hours during a widespread grid outage.”

Not long after the earthquake, the microgrid was called into service multiple times due to winter storm outages, ranging from 30 minutes to 8 or more hours each time. The seamless operation allows county staff to focus on critical tasks and spend less time managing backup generators at the site.

One lesson learned from this innovative project is the need to fine-tune when and how much energy will be discharged from the batteries into the grid. The microgrid includes two main components: a smaller net-metered (NEM) solar array, and a larger solar+storage system. On a typical day, the energy generated from the NEM array feeds directly to the airport and other electric meters to offset their electricity usage. The larger solar array generates energy to store in the batteries and delivers power to California’s wholesale energy market when demand and electricity prices are high. The energy provided to the wholesale market serves either RCEA customer load or provides critical ancillary services to the California Independent System Operator (CAISO), but in all cases the timing is when the grid needs it most. By storing power in the batteries, the microgrid is able to provide clean energy when demand is highest after the sun has set.

The one-two punch delivered by the earthquake and subsequent winter storms prompted RCEA to adjust its operating protocols to retain battery capacity at a 60% minimum reserve when conditions forecast the potential for an outage, rather than letting it go down to around 25% during energy market participation. Although earthquakes remain unpredictable, this “storm watch” approach can improve resilience capacity informed by forecasted weather conditions, .

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

RCEA and its partners will continue efforts to prepare the region for future challenges and help essential services stay online when they are most needed.

For published materials about the microgrid, click on the tabs below: