Energy resilience is the capacity to maintain power in the event of an outage. One path to resilience is through the development of microgrids.
A microgrid is an autonomous power grid that can operate both in tandem with and when “islanded” from a utility grid. At minimum, a microgrid combines onsite energy generation and storage with system controls that allow the microgrid to connect/disconnect from the main grid and to operate independently. Microgrids may also include responsive battery deployment and tiered load-shedding.
Renewable energy microgrids pair onsite resilience with global sustainability. Microgrid storage can help smooth the effects of intermittent power generation (e.g. from solar and wind) and increase overall grid stability. This combination of stability and resilience through renewable energy is the focus of our microgrid work.
Our first microgrid project was the Blue Lake Rancheria (BLR) low-carbon microgrid. Deployed in July 2017, this system integrates a 420 kW photovoltaic array, 500 kW/950 kWh of battery energy storage, and a microgrid management system that is responsive to solar and load forecasts and provides tiered load-shedding. The microgrid enables the Rancheria to function as a regional Red Cross emergency evacuation center — and in September 2017, the Tribe was recognized by the Federal Emergency Management Agency (FEMA) for its outstanding preparedness efforts. The project also won the DistribuTECH Project of the Year award for Distributed Energy Resources (DER) Grid Integration.
Our second project at the Blue Lake Rancheria is a pilot “Solar+” design system. Solar+ systems integrate solar, storage, and advanced controls — functionally, a small microgrid — but are typically beyond the price range of smaller businesses. This project aims to create a replicable system design for gas station/convenience stores. There are 12,000 of these stores within the state of California alone, and many share a similar building plan and energy needs. The project will generate an “out of the box” package to help store owners and energy planners assess site viability and implement solar+ systems.
In 2018, we were awarded a grant from the California Energy Commission to build a renewable energy microgrid at the Redwood Coast Airport — and to demonstrate an effective business case for microgrid deployment. The airport microgrid will include a 2 MW photovoltaic array DC-coupled with a 2 MW, 8 MWh battery storage system, an additional 250 kW net-metered photovoltaic system, and direct interface via the utility power distribution control center. The arrays and battery storage will be owned by the local community choice aggregator, Redwood Coast Energy Authority, and power generated will be sold on the wholesale CAISO market. This project will provide a test bed for the policies, tariff structures, and operating procedures necessary to integrate microgrids into California’s electric grid. Simultaneously, the microgrid will maintain power for the Humboldt County airport and U.S. Coast Guard Air Station, which provide emergency lifeline services for the region.