Close to Home: Microgrid lessons in Sonoma County

Microgrids were birthed in parts of the world where there was no traditional grid. According to Guidehouse Insights, a global consulting firm, Alaska leads the U.S. in installed microgrid capacity, the majority serving remote communities not interconnected with any traditional grid network. California comes in second, though the majority are interconnected to the state’s power network.

The microgrids deployed in California are chiefly a response to wildfires and Public Safety Power Shutoffs, whereby utilities turn off electricity purposely to limit the possibility of any Tubbs-scale event. The advantage of these microgrids, often deployed at military bases and other facilities that cannot tolerate even a blip in electricity supply, is that they can operate when the larger grid goes down. Unlike traditional dirty diesel generators that only operate during an emergency, microgrids can combine renewable energy (i.e., solar), batteries and other resources to keep operating whether the gird is up or down.

A great example of what is possible is the Stone Edge Farm on the outskirts of Sonoma. It operated continuously throughout the Tubbs Fire five years ago and has since operated independently for years, despite being connected to PG&E’s grid, proving it is possible to operate independently of the larger grid whether necessary or to save money.

The focus of a recent dispute between PG&E and Sonoma Clean Power, the community choice aggregation program that decides where electricity comes from for Sonoma and Mendocino counties, is a small pilot project totaling 2 megawatts, enough electricity to provide power to approximately 2,000 homes. (For context, Alaska’s microgrid portfolio exceeds 3,500 megawatts.)

These cookie-cutter standardized microgrids are ideal for nature preserves, telecom towers and other rural sites in high-risk fire areas. The issues before regulators include where to deploy these microgrids, whether to allow customers a choice to go off-grid or not and what energy sources (e.g., solar or fossil) to use. The issue is significant in that community choice aggregators such as Sonoma County’s will be serving almost half of all customers of the state’s three largest investor-owned utilities by the end of next year.

The dispute between PG&E and Sonoma Clean Power is bureaucratic. Yet it could impact not only Sonoma Clean Power customers but other Bay Area community choice aggregators. Will PG&E assess utility fees on these customers even if they do not contribute to any spike in energy prices since they remain disconnected from the larger system? Will other system charges be imposed by PG&E even if customers receive no benefit from investments in the distribution system?

Peter Asmus is executive director of the Alaska Microgrid Group. He lives in Bodega Bay.

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