As peak wildfire season nears, SDG&E completes work on microgrid in Ramona

SDG&E Ramona Microgrid delivers renewable energy and battery storage for wildfire mitigation, grid resilience, and PSPS support, powering the Cal Fire Air Attack Base with a 500 kW, 2,000 kWh lithium-ion system during outages.

It figures to be another dry year — with the potential to spark wildfires in the region. But San Diego Gas & Electric just completed a renewable energy upgrade to a microgrid in Ramona that will help firefighters and reduce the effects of power shutoffs to backcountry residents.

The microgrid will provide backup power to the Ramona Air Attack Base, helping keep the lights on during outages, home to Cal Fire and the U.S. Forest Service's fleet of aircrafts that can quickly douse fires before they get out of hand.

"It gives us peace of mind to have backup power for a critical facility like the Ramona Air Attack Base, especially given the fact that fire season in California has become year-round," Cal Fire/San Diego County Fire Chief Tony Mecham said in a statement.

The air attack base serves as a hub for fixed-wing aircraft assigned to put out fires. Cal Fire staffs the base throughout the year with one two airtankers and one tactical aircraft. The base also houses the Forest Service's Bell 205 A++ helicopter and crew to protect the Cleveland National Forest. Aircraft for both CalFire and the Forest Service can also be mobilized to help fight fires throughout the state.

This summer, the Ramona microgrid won't have to rely on diesel generation. Instead, the facility next to the town's airport will be powered by a 500 kilowatt and 2,000 kilowatt-hour lithium-ion battery storage system that won't generate any greenhouse gas emissions.

"What's great about it, besides that it's a renewable resource, is that it's a permanent installation," said Jonathan Woldemariam, SDG&E's director of wildfire mitigation and vegetation management. "In other words, we don't have to roll a portable generator out there. It's something that can be leveraged right there because it's already installed and ready to go."

Microgrids have taken on a larger profile across the state because they can operate independently of the larger electric grid, where repairing California's grid is an ongoing challenge, thus allowing small areas or communities to keep the power flowing for hours at a time during emergencies.

That can be crucial in wildfire-prone areas affected by Public Safety Power Shutoffs, or PSPS, the practice in which investor-owned utilities in California de-energize electrical power lines in a defined area when conditions are dry and windy in order to reduce the risk of a power line falling and igniting a wildfire, while power grid upgrades move forward statewide.

Rural and backcountry communities are particularly hard hit when the power is pre-emptively cut off because many homes rely on water from wells powered by electricity for their homes, horses and livestock.

In addition to Ramona, SDG&E has established microgrids in three other areas in High Fire Threat Districts:

The microgrids in Butterfield Ranch and Shelter Valley run on diesel power but the utility plans to complete solar and battery storage systems for each locale by the end of next year, as other regions develop new microgrid rules to guide deployment.

SDG&E has a fifth microgrid in operation — in Borrego Springs, which in 2013 became the first utility-scale microgrid in the country. It provides grid resiliency to the roughly 2,700 residents of the desert town and serves as a model for integrated microgrid projects elsewhere in delivering local electricity. While the Borrego Springs microgrid is not located in a High Fire Threat District, "when and if any power is turned off, especially the power transmission feed that goes to Borrego, we can support the customers using the microgrid out there," Woldemariam said.

Microgrid costs can be higher than conventional energy systems, even as projected energy storage revenue grows over the next decade, and the costs of the SDG&E projects are passed on to ratepayers. As per California Public Utilities Commission rules, the financial details for each of microgrid are kept confidential for at least three years.

SDG&E's microgrids are part of the utility's larger plan to reduce wildfire risk that SDG&E files with the utilities commission. In its wildfire plan for 2020 through 2022, SDG&E expected to spend $1.89 billion on mitigation measures.

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