Shoreline explores microgrid for Tomales

01/01/2020

A company that specializes in microgrids will look at how to create one in Tomales, at the behest of Shoreline Unified School District. The district’s board in December approved a memorandum of understanding with the Utah company CleanSpark to conduct a feasibility study on how a microgrid could power critical systems in Tomales during an outage.

The company, whose San Diego office is handling the project, will return to the board in March to present the study, describing how a microgrid can generate power for the school and the surrounding community in a sustainable and economically viable manner.

The project aims to generate more than half of the school district’s energy use in Tomales and reduce current use by 5 percent. Beyond the school district, the grid would allow Tomales residents and workers to use solar energy both as an island or while connected to the Pacific Gas & Electric grid.

The boundaries of the microgrid would be determined by the location of the circuit breakers on PG&E’s grid. Residents would need to be informed to power down both when PG&E is incentivizing de-energization and when the microgrid is the only source of power.

“Should we do our work properly, the community will get behind it, and they will be talking about it in terms of ‘our microgrid,’” said Gerry Vurciaga, CleanSpark’s director of partners and alliances.

The project would include solar panels on the roofs of Tomales High and Tomales Elementary Schools, the Shoreline district office and the maintenance garage. Generators and energy storage would be installed at the high school, and the sites would be connected using PG&E’s lines. 

During an outage, a battery would power the grid for about two hours after the sun goes down, after which a generator would kick in. A second battery under consideration at the elementary school could store power for another two hours.

The high school uses 250,000 kilowatt hours of energy every year, but its roof can support up to 750,000 kilowatt hours a year, Mr. Vurciaga said. By applying for PG&E incentives and selling excess energy to the California wholesale market or to Marin Clean Energy, the microgrid could pay for itself. “We are going to find every dime of savings,” he said.

CleanSpark’s software optimizes every 15 minutes to get the best price on energy, and it can turn off systems when they are not needed. 

PG&E’s automated demand-response program incentivizes businesses to have energy management controls that reduce electricity consumption when demand is high. When the demand and price of energy go up, PG&E asks participants in the program to reduce consumption, then awards rebates based on how much energy is shed. If more residents participate, the district and CleanSpark can recuperate more construction costs. 

 The district will determine what should be turned off during an outage by conducting practices in which the schools would power down to critical loads.

CleanSpark first looked at a microgrid project at Bodega Bay Elementary School two years ago, but it was denied a $3 million grant proposal to the California Energy Commission.

Mr. Vurciaga said he expects to know how much this project will cost the district before his March presentation.

Once the board receives the feasibility study, it will have 120 days to decide whether to move forward. If trustees approve the project, CleanSpark would start a second feasibility study on a microgrid at West Marin and Inverness Schools while securing building permits and an interconnection agreement with PG&E. 

“Believe it or not, PG&E is not always cooperative in terms of doing those interconnection agreements,” Mr. Vurciaga said. Still, he believes construction could begin in the summer and the grid could be operable in September.

In exchange for the feasibility study, which CleanSpark is funding, the district agreed it would not negotiate a microgrid project with another entity until the study is complete, and would return the plans if it declines the project.