The microgrid at University of California, San Diego serves a campus community of more than 45,000 people, 13 million square feet in 450 buildings, 1,200 acres, and generates 80% of the electricity used on campus annually. The campus controls 42 MW of generation, and then purchases power on the market. It has 2, 13.5 MW gas turbines; a 3 MW steam turbine; 1.2 MW of solar; and a 2 MW PPA contact for fuel cell power that uses methane from a wastewater treatment plant. Some call microgrids “localized groupings” of power sources.
Microgrids are a trend that can provide significant benefits. They orchestrate power generation, storage, transport, and use. Already, the energy-intensive university – complete with research labs and a hospital – has banked millions in savings. It is able to connect to the larger electric grid, but can also work independently. It can “island” in a power emergency, disconnecting from the grid and maintaining its own critical functions. In the firestorms of 2007, UCSD switched from being drawing 3 MW from SDG&E, to generating 4 MW of excess power and returning it to the grid, in 30 minutes.
The microgrid more efficiently manages real-time demand, supplying and storing energy at a lower cost with less pollution than a conventional grid. It has a 3.8 million gallon thermal energy storage system that it uses to chill water at night for daytime air conditioning. UCSD reports savings of more than $800,000 in power costs per month because of its microgrid. Students are gaining hands-on experience with the sophisticated control system that manages hundreds of inputs, and even computes cloud patterns and solar shading effects.
Recently, the California Energy Commission approved additional funding for the project. “The return on this investment extends far beyond the San Diego campus,” said Energy Commission Chair Robert B. Weisenmiller. “It provides a crucial real-life demonstration of technology that can help to provide California a future of clean, sustainable and reliable energy.” The CEC has invested nearly $4 million in the microgrid since 2008, leveraging more than $4 million from other funding sources, public and private.
The Commission’s funding will also enhance the vehicle charging network at UC San Diego. By June 2013, the university expects to have a total of 54 charging outlets, with more than 70% available for public use. Already, nearly half of the university’s fleet of more than 800 vehicles has been converted to near-zero emission vehicles. Diesel fuel has been replaced with ultra-low sulfur biodiesel, and buses, street sweepers, cars and trucks have been converted to run on compressed natural gas. The fleet also includes five Nissan Leafs and more than 50 hybrids.
Microgrids are of particular interest to the military. Over 40 Department of Defense bases either have a microgrid or are in the process of establishing one. Naturally, they enable military bases to sustain operations no matter what is happening on the larger utility grid, or in the theater of war. The average capacity for the microgrid bases is 54.8 MW.