This California city is trying a community microgrid to improve resiliency against wildfires, PG&E shutoffs


The City of Calistoga, Calif., is in Pacific Gas & Electric (PG&E) territory, and therefore subject to PG&E’s Public Safety Power Shutoffs (PSPS) during times of high fire danger. The city experienced two PSPS warnings last fall, and a 48-hour shutoff disrupted the city and led to lost revenue for local businesses. With a severe fire season predicted for California this year, PSPS are likely to increase in frequency and duration.

As a result, Calistoga is exploring new ways of designing its grid. The city entered into an agreement with the Clean Coalition this week, a California nonprofit organization, to conduct a feasibility assessment for a community microgrid as one possible new approach. The microgrid would be connected to the larger power grid, but during a power outage a renewables-driven community microgrid can “island” from the grid and keep critical facilities online indefinitely.

The Clean Coalition has a long history of designing and staging community microgrids, most recently for the wildfire-ravaged California areas of Ventura and Santa Barbara Counties, as well as the North Bay. Increasingly, municipalities that have not yet experienced disasters are considering this modern energy system to provide their communities an unparalleled trifecta of economic, environmental, and resilience benefits.

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PG&E is currently investigating the potential for enabling temporary diesel generation to supply power to part of the city during a PSPS through a new preinstalled interconnection hub (PIH). The city and PG&E hope to complete construction of the PIH by mid-September. While the PIH will support some of the city’s businesses and residents during PSPS, it will not power the whole city. As currently envisioned, areas west of the river and those in proximity to severe high-fire-threat zones will remain unpowered during a PSPS. In addition, diesel generators are heavy polluters and are expensive to maintain. They do not provide the real energy resilience that community microgrids will bring to the area.

“The Clean Coalition is excited about the opportunity to design a truly resilient power system for Calistoga,” said Dr. Frank Wasko, Managing Director of the Clean Coalition. “With their vote to proceed with the Community Microgrid project, the forward-thinking Calistoga City Council has shown they understand what it takes for their community to thrive in California’s new normal.”

The project will start with a few microgrids at discrete locations, with the ultimate goal to develop a Community Microgrid that serves the full Calistoga substation grid area.

As part of the site assessment, the Clean Coalition will conduct a Solar Siting Survey to identify the commercial-scale solar siting potential in Calistoga. The Clean Coalition’s Solar Siting Survey methodology has successfully identified ample solar siting opportunities in urban and suburban environments; predominantly on buildings, parking lots, and parking structures.

The Clean Coalition will follow the site assessment with functional designs for five target microgrid sites and a broader Community Microgrid that serves the entire City of Calistoga. In addition, the Clean Coalition will engage key stakeholders in preparation for the next project phases: permit-ready, finance-ready microgrid designs and construction thereof.

— Solar Builder magazine


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