Microgrid Near Yosemite Provides Power 24/7, Eliminates Line-Sparked Fire Risks

8 Jun 2021

Pacific Gas & Electric has launched a new microgrid system powered by a solar array paired with batteries to provide continuous power to a tiny community in a high fire threat area close to Yosemite National Park. The standalone system, which also includes backup propane tanks, is in place of new power lines across mountainous terrain in the town of Briceburg, off of Highway 140 in Mariposa County. The previous wires were destroyed by a wildfire in 2019.

“Replacing these long distribution lines with a reliable and low-carbon local energy source is an innovative option that has now become feasible,” PG&E stated June 7. The new system serves two households, a visitor center, and telecommunications and transportation facilities. 

“This is a positive development,” Ed Smeloff, Vote Solar director of grid integration, said. “It makes sense to decommission remote distribution lines” in the high fire threat area.

Source: BoxPower

PG&E’s new system was built by BoxPower based in Grass Valley and is made up of a 36.5 kW solar array and a 27.2 kW / 68.4 kWh lithium ferro phosphate battery. It comes with two integrated 35 kW propane generators for backup power, and a fire suppression system. The islanded system is considered more reliable and less fire prone and costly than what the site had before, according to PG&E. 

“PG&E foresees that even taking into account future maintenance, fuel, and component replacement costs within the standalone power system, the remote grid solution is expected to be the lowest risk and cost option for Briceburg,” utility spokesperson Paul Doherty stated in an email.

Last year, the utility began contracting for around 300 MWs of diesel backup systems for high fire threat areas, raising serious health concerns. Propane is less flammable and is delivered in tanks routinely to rural communities. It also is less polluting than diesel. “Propane is a good fit for permanent installations where the type of fuel storage tank and piping can be left in place: for PG&E’s standalone power systems we expect to refill the propane tank about twice a year,” according to Doherty.

Meanwhile, legislation to address the growing gap in who is able to set up microgrids in California, by providing support to communities seeking energy resilience, awaits a hearing by the Assembly Utilities & Energy Committee. SB 99 by Sen. Bill Dodd (D-Napa), which passed the Senate at the end of May, would provide money and technical assistance for local governments to install clean community microgrids at critical facilities. The funding and assistance would come from the California Energy Commission. In addition, the California Public Utilities Commission is working on the second phase of its proceeding to commercialize clean microgrids, as required by legislation.

PG&E’s hybrid stand alone project, approved through the CPUC’s advice letter process, is a subset of multi-customer microgrids under debate.

The utility is exploring using this kind of power system in other remote areas served by power lines strung across risky fire areas to provide “enhanced reliability with a lower risk profile and at a lower total cost,” Jason Glickman, PG&E’s Executive Vice President, Engineering, Planning and Strategy, stated. The company hopes to have 20 remote renewable grids up and running by the end of next year, Doherty said. It’s also looking at putting new installations in parts of El Dorado, Mariposa, Tulare, and Tehama counties.

PG&E said it and developer BoxPower will be able to monitor and control the new system in Briceburg via satellite and cellular connectivity. The system also includes remote performance safety diagnostics, alarms, and automated refueling notifications.

Vote solar backs the Briceburg project as a pilot, which is folded into rates. It hopes the pilot is significantly expanded, as expected, because renewable microgrids work well in remote communities. But if so, it should be put out for competitive bidding to allow third party suppliers, Smeloff said.

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