The construction of five hybrid microgrids at municipal sites in the city of Camarillo is progressing after its council unanimously approved the concept.
The Oct. 28 decision was based on a feasibility study conducted by the Clean Coalition and TRC Cos.
The sites selected are City Hall, the corporation yard, the public library, the police station, and the wastewater treatment plant. The microgrids will utilize solar plus storage and diesel and are projected to save the city $500,000 a year over the 30-year expected project life span.
Four of the sites will use all three generation resources, while the Camarillo Public Library microgrid will implement solar plus storage only. The wastewater treatment plant and police station already have diesel generators in place. Each site is being designed to provide at least 120 hours of continuous power for emergency use during outages.
The Clean Coalition, a Santa Barbara-based nonprofit, and TRC were contracted by the city in February to provide a feasibility study for the five sites. While the Clean Coalition was the lead, TRC provided detailed technical support on system design and economic analyses.
The city originally planned to rely on existing diesel generation as its emergency power backup; however, the study looked at various options based on 150 percent of normal loads for outages of five days. The analysis ultimately determined that behind-the-meter hybrid systems would be the most feasible and economic solution.
"Combining solar plus storage and diesel into a hybrid solar microgrid will provide the city with a resilient system that can handle the more frequent, shorter-term one- to two-hour outages with solar plus storage alone, with a diesel generator to be used only when needed for longer-term emergency outages," Frank Wasko, managing director for the Clean Coalition, told California Energy Markets via email. "For outages of a week or more, while the diesel could run dry, the solar plus storage can support about 20 percent of the most critical loads at each site indefinitely."
Wasko added that in the event of a natural-disaster-related outage that extends beyond the five-day period studied in the feasibility report, "it's possible that roads will be blocked, prohibiting diesel refueling. In those cases, it would be possible to support the most critical loads indefinitely with just the solar plus storage resources.
"The target," he added, "is to minimize how often the diesel generators are run as well as to minimize fossil fuel use and carbon emissions when they are run. The solar is sized for zero net energy, which offsets 100 percent of the carbon emissions from any utility-supplied electricity."
The microgrids are also anticipated to reduce the locations' combined carbon footprint by 88 percent and to provide utility bill savings, which will be dictated by the financing model the city chooses.
Southern California Edison, Camarillo's incumbent utility, cut service to two lines feeding the city during 2019 public-safety power shut-offs. One PSPS was 21 hours in duration and another lasted 88 hours. Wasko said there is no data yet for 2020. "While none of the sites examined in this study were on these impacted feeders, it is clear that PSPS events are affecting the city," he said, "and like any good city, the City of Camarillo is taking action to ensure resilience for its critical community facilities."
Financing and the actual cost of the project have yet to be determined. Michelle D'Anna, community relations officer for the City of Camarillo, said city staff estimates it will be a $20-million project, $15 million of which the city expects to fund through a Federal Emergency Management Agency grant for projects such as microgrids and generators that can help communities weather natural disasters. If successful, the city intends to match the grant with $5 million from its capital improvement funds.
Wasko said the actual costs will be based on the financing mechanisms chosen and on power-purchase agreement terms. He said the city is exploring "granting opportunities . . . that could cover significant portions of capital expenditures, which would enhance the associated economics for the city."
Based on the outcome of the grant application, City of Camarillo staff will determine what financing will be required to complete the projects, which could include changing the design of one or more of the microgrids, D'Anna said.