San Diego Utility Plans to Make Borrego Springs Microgrid Entirely Renewable

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San Diego Gas & Electric plans to upgrade its Borrego Springs microgrid so that it can run entirely on renewable energy.

Borrego Sprints

By chinasong/

SDG&E received a $4.5 million grant from the US Department of Energy’s Solar Energy Technologies Office to buy smart power inverters, controls and a state-of-the-art energy management system. The utility is contributing $1.4 million to the project.

The equipment and software will improve energy reliability, stabilize the microgrid and help it become completely renewable, according to the utility.

The DOE sees the technology developed through the project allowing more flexibility for interconnecting and operating small-scale photovoltaics and other distributed energy systems.

The microgrid is connected to a 26-MW solar field and 1.5 MW of battery storage that can deliver 4.5 MWh before needing to be recharged, according to the National Renewable Energy Laboratory, a partner on the project. 

But unstable voltage conditions and solar output fluctuations make it hard to run the grid entirely on solar power. The microgrid also has backup diesel generation totaling about 4 MW.

“This grant award comes at a pivotal time for our customers, our company and the next evolution of microgrid technology,” said Will Speer, vice president of electric engineering and construction for the utility. “With the smart grid technology that we will incorporate into the microgrid, we are confident that this facility can become a model for future clean energy microgrids.”

The utility set up the microgrid in 2013 to improve energy resilience for the roughly 2,800 people in Borrego Springs, which is served by a 60-mile power line that can be cut off because of storms, fires and high temperatures. It was the first utility owned microgrid.

Now, the utility operates two microgrids and is building four more that are set to be online later this year and in 2021 as part of a plan to reduce the effects of wildfires. 

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“SDG&E continues to explore microgrids, energy storage and other types of backup power solutions throughout the region as ways to keep power flowing to customers during emergencies or other situations that may result in outages,” the utility said.

The Borrego Springs microgrid was selected as one of 75 projects that will receive a total of $128 million under SETO’s 2019 funding program.

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The program provides funding for research projects that advance early-stage solar technologies that will lower electricity costs, boost US solar manufacturing, reduce red tape related to installing solar energy systems, and make solar systems less vulnerable to cyberattacks.

Borrego Springs is one of several winning projects focused on better integrating solar facilities, especially by increasing coordination and control of power electronics to quickly restore outages and improve the ability to respond to events like fires and cyberattacks, according to DOE.

SDG&E expects to install the new technology by the end of next year. 

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  1. Brady Fennell says:

    What is the plan for replacing the back up diesel generator? Has any thought been given to replacing with a fuel cell possibly one with an electrolyzer so the hydrogen can be manufactured from H2O rather than natural gas?

  2. “But unstable voltage conditions and solar output fluctuations make it hard to run the grid entirely on solar power. The microgrid also has backup diesel generation totaling about 4 MW.”

    Some of the large scale utility energy storage online around the World has proven with as little as 10% capacity reserve, one can supplement and operate the grid. This also points to building these energy storage facilities with 30 to 50% capacity and clipping in the solar PV farm, where the D.C. to A.C. buss ratio is 1.5 to 1. By changing out solar PV strings with the latest/greatest solar PV panels and replacing string inverters with 1,500 VDC inverters, one could get another 30% out of the same space and get to a 1.3 to 1 buss ratio. This now makes the site more amenable to a larger energy storage system. The next move is to get away from the 3 hours back up concept and get into the 8 to 12 hours back up energy storage point.