Case Studies: Clean Microgrids Provide Grid Resiliency in California
Clean microgrids are small energy systems, typically combining distributed renewable energy like solar panels with batteries and a control system. They can be big enough to power whole college campuses or military bases, or small enough to power a single home. Under normal circumstances, the clean energy generates power for the customer and the battery can provide load-shifting or peak-reducing services. When the grid goes out, the microgrid can “island,” disconnecting from the grid and serving some or all of the customer’s electricity needs.
California is a national leader in clean microgrids. In this report we have collected a sample of five clean microgrids operating or being built around the state, serving a wide range of customers. As climate impacts grow and public safety power shutoffs continue, Vote Solar strongly supports removing barriers to the growth of clean microgrids as a means of promoting public safety and resiliency.
Many, although not all, of these microgrids have been supported by state R&D grants. Since 2009, the California Energy Commission has disbursed a total of $84.5 million to build 20 new microgrids across the state, focused on demonstrating microgrids on critical facilities and on microgrids with high levels of renewable energy. Grant funding for the projects has come from the Electric Program Investment Charge (EPIC), a ratepayer-funded energy innovation research program.
1. Blue Lake Rancheria Microgrid
The Blue Lake Rancheria is located on tribal land in the Humboldt Bay area, nearly 300 miles north of San Francisco. It sits at the junction of three tectonic plates and is subject to heavy rainstorms, forest fires, and frequent power outages. The Rancheria houses tribal government offices, EV charging, a convenience store and gas station, a hotel and casino, and energy and water systems — including a low-carbon microgrid.
In addition to serving the Rancheria, the microgrid also serves as an American Red Cross emergency evacuation site. During the October 2019 power shutoff, the Rancheria housed eight people with acute medical needs in its hotel. The County Department of Health and Human Services credited the Rancheria with saving their lives.
| Ownership | Customer-owned |
| Online Date | 2017 |
2. City of Fremont, Fire Stations Microgrids
The City of Fremont won a state grant to develop microgrids at three fire stations. Each microgrid consists of a parking lot canopy photovoltaic system, battery energy storage, and an energy management system that controls the system automatically. During an outage, the microgrid will provide at least three hours a day of power for critical loads. It was designed and installed by Fremont’s Gridscape Solutions.
A four year trial period recently ended, and the project is now fully operational. It has saved Fremont $32,000 in utility bills already, and will save another $215,000 over ten years, along with cutting carbon dioxide emissions by around 80,000 pounds per year.
| Ownership | Third party-owned |
| Online Date | 2015 |
3. Stone Edge Farm Microgrid
During the Sonoma County fires in 2017, the Stone Edge Farm microgrid operated continuously for 10 days while neighbors lost power as a result of wildfires. It again rode through PG&E’s Public Safety Power Shutoffs in the fall of 2019.
The microgrid at the farm, spa and vineyard features solar, a fuel cell and hydrogen electrolyzer, a microturbine, and 10 types of batteries, plus offers educational tours. Even when the farm was evacuated, operators continued to manage the microgrid’s operation remotely.
| Ownership | Customer-owned |
| Online Date | Now operational: developed between 2013 and 2018 |
4. Santa Rita Union School District Microgrids
Santa Rita Union School District serves about 3400 kids near Salinas, many of them Latino and from farm worker and other low-income families. About 90% of the kids qualify for free or reduced lunch. The district sees power outages fairly regularly because they are rural with a constrained grid in the Monterey Bay area. In 2016, school leadership looked into getting backup power, and while they considered diesel generators they decided to take a cleaner path. While there are ~ 2000 schools in California with solar panels, and over 5000 nationwide, very few are equipped with batteries to provide power during outages.
Santa Rita Union installed solar + storage at seven of their schools. The solar savings generated by net metering are being used to repay the cost of the system. The storage can discharge for up to 7 hours, while the solar will recharge the storage every day, making the system able to provide power indefinitely. The middle schools are designated emergency shelters; the microgrid allows community members to sleep in the gym, get medical care, and charge their devices. The kids can also keep attending school during long power outages and continue receiving 1-2 free meals a day, an important service to the community.
| Ownership | Third party-owned |
| Online Date | Operational late 2018 |
5. Microgrid at Marine Corps Air Station Miramar
The Marine Corps Air Station (MCAS) Miramar in San Diego is completing a multi-faceted microgrid, involving solar, landfill gas, diesel and natural gas, energy storage, and hybrid electric vehicles that can provide power to buildings. The microgrid can electrify the base’s 100 mission critical buildings, including its entire flight line, even during a power outage.
The microgrid can run on “island mode” when disconnected from the grid, or in “economic mode” to reduce the base’s utility bills and support the grid for the community. In addition to the energy savings, the system can cut demand charges that can add up to $41,600 a month.
| Ownership | Customer-owned |
| Online Date | 2019 |