National Renewable Energy Lab studies San Diego microgrid

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San Diego Gas & Electric Company, in collaboration with the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL), installed a microgrid in an area north of San Diego that’s prone to electrical outages.

The microgrid is located in Borrego Springs, Calif., an area where monsoons, winds, and flooding often knocks out power.

Microgrids are self-powered electric grids that can either operate independently or connect to the larger grid. They can disconnect from the main grid during outages and continue to operate independently.

“Borrego Springs is on the eastern edge of our service territory,” Tom Bialek, SDG&E chief engineer, said. “You get these monsoonal rains that occur and cause flash floods, and there’s a lot of talk in our region on energy resilience because we’re in an area that faces significant wildfire threats. Due to our complex topography and strong Santa Ana winds, San Diego and Southern California are the most conducive to rapidly expanding wildfires anywhere in the United States and perhaps the world. These winds get to be hurricane force. That’s what people don’t appreciate. We’re looking at Category 1 to Category 2 winds down over the mountaintops coupled with low humidity and dry, dead fuel. In this environment, all it takes is a single spark and fires will spread very, very quickly. From a resiliency perspective, that’s why this is really important.”

NREL is working with SDG&E to understand better is how a microgrid controller with advanced technology would perform. NREL is exploring this from its Energy Systems Integration Facility (ESIF), which houses NREL’s megawatt-scale microgrid test platform.

“We have an amazing modeling and simulation capability to bring in feeder data from SDG&E and be able to answer ‘what if’ questions with multiple devices, not just with a single component, utilizing our power hardware-in-the-loop capability,” Martha Symko-Davies, Energy Systems Integration laboratory program manager, said. “That’s the key of what ESIF can do: de-risk and implement the technology in Borrego Springs.”

NREL obtained the modeling data from SDG&E to set up the simulation.

The collaboration between NREL and SDG&E may advance important technologies and provide ideas that other researchers can use.

“The goal is for others to have this data so they can learn,” Symko-Davies said. “What we do here is so critical to others. The ability to do power hardware-in-the-loop and having the 2-megawatt grid simulator to de-risk and answer those ‘what-if’ questions are key. That’s what distinguishes us from other national labs. If you don’t de-risk this and make sure it’s credible, people start questioning the technology. It can ruin the whole market for what we’re trying to do.”

Lessons learned from this project will be used to develop the Institute of Electrical and Electronics Engineers standards around microgrid controller testing.

“How do we think about where we want to be in the future?” Symko-Davies said. “How do we reach these goals? If we don’t do the research here and connect with utilities like SDG&E, we don’t get our tech out of the lab.”