Installing the microgrid in November allowed the utility to turn off a line that provided power to the site of the Gem Dam, part of the Rush Creek Hydroelectric Facility, located 8,900 feet above sea level close to Yosemite National Park, said Sarah Loyola, major construction project manager for SCE and the project.
The line powered valves, emergency backup, cameras and other equipment needed to ensure the dams were running properly.
“We turned off the line and came up with an alternative way to power the site that was independent of the grid,” said Loyola.
The microgrid, completed in early November, includes two 3.3 kW solar arrays, a 600-amp, 48-volt storage system and a propane backup generator.
Genesis of solar microgrid
SCE removed the line after detecting wildfire risk, said Stephanie Fincher, generation branch lead for the project.
“The genesis of this microgrid solution stems from one of our efforts doing inspections for wildfires,” she said. “We uncovered some issues with the line that posed a wildfire risk.”
The power line that posed the risk connects the Rush Creek powerhouse and the Gem Dam, she said.
“The team needed a creative solution that could be deployed quickly,” said Fincher. The high elevation, time pressure and difficulty accessing the site created the urgency.
“We had to get it installed before snow would block out availability to do anything,” she said.
In general, SCE inspects electrical infrastructure for anything that could be wrong with the line or vegetation too close to the line, she said.
“We couldn’t just turn the line off and leave the facility without power in the dark. The line supplied emergency power if there was an issue. Without it, we wouldn’t have any visibility into the dam.”