Culver city commissioned Willdan Group to conduct the feasibility study, which was completed in March 2019, with the dual objectives of saving money and energy.
Willdan’s study laid out three scenarios. All involve a senior center and possibly a veteran’s center in the city.
The first calls for a 469 kW solar power installation with a 404 to 522 kWh battery energy storage system at an estimated cost of $2.5 million. The second calls for a 351 kW solar system paired with a 484 to 1,722 kWh battery at a cost of $4.2 million. The third option is a full microgrid in which four electric meters would be consolidated into one in front of a 751 kW solar array and a 676 to 1,651 kWh battery at a cost of a little over $5 million.
“Our recommendation is for the full microgrid, but we are still looking at the options for how to fund it,” said Charles Herbertson, Culver City’s city engineer and director of public works.
In the first scenario, the solar installation at the senior center would be over built so as to provide a net metering credit for the veteran’s center. The second scenario would have solar arrays on both buildings. The first and second options could both provide Culver City with cost savings, but they do not address the city’s resiliency goals.
The third scenario would maximize both solar and storage capacity. “That is preferred because it would allow us to operate almost indefinitely,” Herbertson said. “One of our goals is to have an emergency center.”
Many municipalities in California are embracing microgrids as a way to avoid the disruptions that result from the public service power shutoffs (PSPS) that investor owned utilities are imposing to mitigate the risk that their transmission lines could cause wildfires. Some of those municipalities have been able to secure funds for microgrids, but Culver City is not considered to be in a high risk wildfire area.
The city applied for a grant from the Federal Emergency Management Agency, but did not receive it. The city is also investigating grants from other sources, such as the California Energy Commission, Herbertson said. And the city is in discussions with third parties regarding potential public-private partnerships that could provide a path to lowering the costs of installing the municipal microgrid.
Ameresco proposal to improve resiliency, economics
One of the parties Culver City is in talks with is Ameresco, which has made a presentation to the city council’s sustainability subcommittee. Ameresco floated an idea to lower the solar component of the microgrid and include combined heat and power (CHP) that would provide greater resilience while improving the project’s economics. The CHP plant would do so by not only providing electricity but also heating the city pool. The city currently has a separate facility to heat the pool’s water.
It would be attractive to have two different sources of backup power, batteries and a gas-fired generator. It would make “being resilient more cost effective,” Herbertson said. But there are always trade-offs. The city would be less reliant on solar power but more reliant on natural gas. In addition, some stakeholders would like to see more electrification as a way of lowering the city’s greenhouse gas emission levels. Earlier this month, Mountain View and Morgan Hill became the 11th and 12th communities in the state to pass policies calling for electrification in new buildings.
Possible RFP in 1st Q
In that sense, the microgrid proposal could come down to a debate between resilience and zero or low carbon emissions. Meanwhile, barring a large grant to pay for at least half the cost of the microgrid, it seems likely the city will pursue a public-private partnership, Herbertson said. However, the city council is generally not comfortable going with a proposal from a single company and will likely be developing an RFP, he said.
Right now, city officials are mulling over their next step. If the RFP does move forward, it would most likely be developed during the first quarter and be sent out in second quarter 2020, Herbertson said.