San Diego Gas & Electric to tie microgrid into NRG solar facility

The California Energy Commission (CEC) recently awarded San Diego Gas & Electric (SDG&E) a nearly $5 million grant to expand the innovative Borrego Springs Microgrid.

The grant will allow the microgrid to use the nearby 26-MW Borrego Solar facility to power the entire community, making this one of the nation’s largest microgrids that can operate solely on renewable energy, said the utility on Feb. 17. In addition to bringing in more clean power, the funding will be used to increase the size of the microgrid to service all of Borrego Springs, further enhancing local reliability and reducing the duration of power outages.

“SDG&E is very proud to receive this award from the California Energy Commission,” said James P. Avery, SDG&E’s senior vice president for power supply. “This funding will create a true renewable energy Microgrid, one that not only bolsters local electric reliability, but does so by using the cleanest resources available.”

The Borrego Springs Microgrid uses advanced technologies – including local power generation, energy storage, and automated switching – to create a more resilient local grid. The microgrid is connected to the centralized energy grid, but can disconnect from the larger grid and function independently during emergencies, supplying electricity to the local community through its onsite resources. The microgrid has already kept electricity flowing to the community during several power outages, demonstrating its potential to benefit all customers. 

SDG&E will connect the microgrid to NRG Energy‘s 26-MW Borrego Solar facility, using this clean energy to power the entire town during the day. The challenge is that renewable energy is intermittent by nature and requires back-up resources when solar becomes unavailable, such as at night or when a cloud moves in front of the sun. The microgrid’s large batteries will account for this intermittency in supply and smoothly integrate renewable resources onto the local grid. The batteries also will store the solar power generated during the day for use at night. If the batteries exhaust all their power, the system would access traditional onsite generation.

SDG&E will expand the size of the current microgrid from serving approximately 1,000 customers to incorporate all 2,800 metered customers who live in Borrego Springs. If a large outage were to impact the whole town, the microgrid can switch from running in parallel with the main grid, to “islanding” mode, when the microgrid runs on its onsite generation resources. The expansion of the microgrid is expected to be completed by mid-2016. With the ongoing success of this microgrid project, SDG&E said it is looking into the benefits of developing microgrids in other locations of the grid.

SDG&E is a regulated public utility that provides safe and reliable energy service to 3.4 million consumers through 1.4 million electric meters and 878,000 natural gas meters in San Diego and southern Orange counties. The utility’s area spans 4,100 square miles.

About Barry Cassell 20414 Articles
Barry Cassell is Chief Analyst for GenerationHub covering coal and emission controls issues, projects and policy. He has covered the coal and power generation industry for more than 24 years, beginning in November 2011 at GenerationHub and prior to that as editor of SNL Energy’s Coal Report. He was formerly with Coal Outlook for 15 years as the publication’s editor and contributing writer, and prior to that he was editor of Coal & Synfuels Technology and associate editor of The Energy Report. He has a bachelor’s degree from Central Michigan University.