The California Energy Commission recently awarded San Diego Gas & Electric (SDG&E) a nearly $5 million grant to expand the 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. 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.
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 vital 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’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 abundant solar power generated during the day for use at night, when solar is unavailable and the microgrid powers the most critical loads in the community, such as cool zones, gas stations and grocery stores. If the batteries exhaust all their power, the system would access traditional onsite generation. SDG&E will use new computer software to make sure all these transitions happen seamlessly and maintain a consistent flow of power to the community.
As it becomes more sustainable, the microgrid also will grow in scope. SDG&E will expand the size of the current microgrid from serving about 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. This means that the microgrid can keep electricity flowing during an emergency or other grid disturbance, enhancing reliability for the whole community. The town will also be running on locally-sourced renewable energy, making the system greener and more sustainable overall.
The expansion of the microgrid is expected to be completed by mid-2016. With the ongoing success of the microgrid project, SDG&E is currently looking into the benefits of developing microgrids in other locations of the grid. This project demonstrates SDG&E’s ongoing commitment to developing an innovative electric grid that supports the needs of customers, protects the environment and fuels economic growth through green technology.
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