Microgrid: Keeping the Lights On

Most of us don’t give electricity much thought. We flip a switch and a light comes on. We set our thermostats and forget them until the seasons change. 

The campus community at UC San Diego is no different. Most of the University’s 45,000 students, faculty and staff go about their business each day, never giving the electric grid a second thought. Power is there whenever they need it, wherever they need it—in their labs, offices, or dorms. 

 “It is our goal to ensure a reliable, safe and secure supply of energy,” says Gary Matthews, vice chancellor of Resource Management and Planning who oversees the electrical power system at UC San Diego,  “and we continuously look for the most efficient and innovative ways we can meet this need.”

In this respect, the campus is just like any other large commercial or industrial site, striving to ensure a steady, economical supply of electricity. But the University goes about doing this in very creative ways. 
 

The Modern Microgrid

At UC San Diego, the key to “keeping the lights on” is the campus microgrid. Considered one of the most advanced in the world, the microgrid generates 92 percent of the electricity used on campus annually and saves more than $8 million, when compared to importing energy.

But what is a microgrid and how does it work?


"Heat-exchanger 1" recovers heat that had previously been wasted (i.e sent into the atmosphere). The equipment was added during an energy efficiency project in 2011
“A microgrid is basically a small-scale version of a traditional power grid,” explains John Dilliott, UC San Diego’s energy and utilities manager. “It draws energy from clean sources such as wind and solar power, as well as from conventional technology. A microgrid can be connected to a larger electric grid, but can also work independently.”

The basic concept behind a microgrid—the idea of localized power generation—is not new. Prior to World War II, most utility grids were fairly self-contained, with power plants located close to the markets they supplied. It wasn’t until the middle of the 20th century that utility grids became today’s sprawling networks. Central power generation facilities new distribute power to homes and businesses hundreds of miles away. 

In the last 10 years however, the modern microgrid has emerged as an alternative to the local utility and is a growing global business. Microgrids have evolved from controlling simple generator backup systems into sophisticated smart grids that can ensure reliability, resiliency and energy independence. 

The ability to work independently from the larger utility grid, known as “islanding,” makes the microgrid attractive to many of its proponents. These include universities like UC San Diego, the military, commercial/industrial and community/utilities. In the event of a regional power outage, a microgrid can disconnect from the utility grid, effectively turning itself into a self-sustaining energy island.

For example, when Hurricane Sandy hit the East Coast in October 2012, it caused billions of dollars in damage. It brought  down power lines and interrupted the supply of electricity to 3.5 million homes and businesses. But thanks to microgrids, places such as the U.S. Food and Drug Administration’s research center and Co-Op City, a large housing cooperative in the Bronx, New York, kept the power on as they disconnected from the larger grid.

UC San Diego’s microgrid is capable of a similar feat. And that is no small achievement for a campus that does $1 billion a year in its research facilities. 

“At a research university like UCSD, the importance of ensuring a reliable source of energy cannot be overstated,” says Byron Washom, director of strategic energy initiatives. “We have an electron microscope that every time we have a supply disruption, it takes six weeks to recalibrate. We can’t let that happen.”


A System in Harmony

So what makes up the microgrid at UC San Diego? It is an integrated system of energy sources and energy storage along with the sophisticated software that controls it. “Everything must work together in harmony,” Washom says.

Currently, power is produced from several key sources: a fuel cell, solar, and a cogeneration plant. 

Fuel Cell: The 2.8 megawatt fuel cell is the largest such cell on any college campus and provides about 8 percent of UC San Diego’s total energy needs.  The fuel cell utilizes methane gas, turning it into electricity without combustion. Instead, there is a chemical reaction between hydrogen atoms and oxygen molecules, yielding water and electricity. The Point Loma Wastewater Treatment Plant provides the purified methane, which is then injected into an existing gas pipeline to supply the UC San Diego fuel cell as well as two fuel cells at City of San Diego sites.

Solar: Solar power comes from 2.3 megawatts of conventional flat panel photovoltaics (rooftop solar) and two sun-tracking, light-concentrating photovoltaic arrays.

Cogeneration: The award-winning 30 megawatt natural-gas-fired combined heat and power system provides 85 percent of the campus’s annual electricity needs and saves $8 million a year in energy costs. The plant generates electricity to run lights and equipment and produces steam for heating, ventilation and air conditioning for the campus. At night, water chillers fill a 4-million-gallon storage tank with cold water.  The water is then used during the warmest time of day to cool campus buildings.

All together, these power generation assets provide 35.1 megawatts of power, which equates to about 75 percent of the campus’ peak power demand. Any additional power needs are provided by San Diego Gas & Electric (SDG&E), the local utility.

But power generation, while critical, is not the only key component of the campus microgrid. Energy storage is another vital piece of the microgrid and an emerging technology the University is helping to advance.

 
Energy Storage

The idea behind energy storage systems is to store the energy created by renewable resources—because the sun doesn’t always shine and the wind doesn’t always blow—so it can be used at other times when needed. The technology is considered key to enhancing grid reliability and is critical to a resilient, efficient, clean and cost-effective grid.

 “UC San Diego has one of the most diverse energy storage portfolios of any university in the world,” says Matthews. “We are currently using or testing several different types of battery/chemical storage systems, an ultracapacitor-based system and a thermal energy storage system. We know that energy storage has the potential to transform the global energy landscape and we’re proud to be a part of that effort.”


Innovation Pays Off

UC San Diego’s success in developing a pioneering microgrid is due in no small part to its ability to leverage government funds and grants as well as form strategic partnerships. The nearly $4 million the California Energy Commission has invested in the microgrid and related research since 2008 has been leveraged to garner more than $4 million from other funding sources, both public and private. 


Power is supplied to campus by three separate SDG&E feeders that merge at a single connection point at the East Campus Switching Station (ECSS)(there are three to allow for failure of any come). Power is also provided by the on-campus energy sources.
Known for being one of the greenest universities in the nation, UC San Diego set a goal several years ago of becoming a carbon-neutral campus by 2025. And just last year, SDG&E presented the University with a $7.2 million check representing energy efficiency incentives earned through implementation of 30 energy efficiency projects from 2010 to 2012. The campus has also garnered approximately $5 million in California Self Generation Incentive Program funds, and other funding, to procure additional photovoltaic and stand-alone electric energy storage. 

“We are continually building on efforts to reduce our carbon footprint,” says Matthews. “The microgrid is a vital part of our comprehensive approach to creating a sustainable campus.”

As a result of the University’s willingness to innovate and share those innovations, the campus microgrid has been touted as a model by the California Energy Commission and the U.S. Navy, and  highlighted in a variety of media outlets including Bloomberg News, Forbes Magazine and the New York Times. It has also been recognized with a U.S. Environmental Protection Agency Energy Star Award and was named SDG&E’s 2013 Energy Grand Champion among many other awards for energy efficiency and sustainability.

“Our goal has always been to supply and use the energy as efficiently as possible,” says energy and utilities manager Dilliott. “But we also want to show others that it can be easy to do as well as cost-effective. Sharing that knowledge and being a part of something this innovative—that’s why it’s so exciting to work here.”


Laura Margoni is a communications officer at UC San Diego