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UCSD Microgrid represents more cost-effective, energy efficient solution to greenhouse gas reduction

San Diego, CA, USA
The Atlas Community Team

Cost

Initial:
13 Million USD

Project Status

Operational since 2018

At a Glance

As part of the UC campus-wide initiative to reach net-zero greenhouse gas emissions, the University of California, San Diego built up its microgrid with a cogeneration plant and solar power, creating a more energy-efficient cost-saving alternative to a standard power grid.

Problem Addressed

Serving a campus community of more than 45,000 people, 13 million square feet in 450 buildings, and 1,200 acres, the University of California, San Diego (UCSD) is faced with providing a lot of energy. With California announcing a succession of challenging carbon reduction goals, schools state-wide are being pushed towards clean energy. The Carbon Neutrality Initiative commits all UC campuses to net-zero greenhouse gas emissions from buildings and vehicle fleets by 2025.

Built from scratch in the 1960s, UC San Diego has always had innovative energy technology. One unique feature was a campus district heating and cooling system constructed on open land that allows for efficient distribution of chilled water around the campus, cooling buildings while avoiding fossil-generated electricity for air conditioning. While this put UCSD in an advantaged position for green energy infrastructure, with 2025 approaching the campus knew they needed to do more if they were to reduce net zero greenhouse gas emissions.

University of California, San Diego used/is using the world's most advanced microgrid to address this/these challenge(s).

Solution(s) Used

With its own microgrid, UCSD is able to generate 85% of its own energy, at about half the price that utility power would cost.

The campus's cogeneration plant, "Central Utilities Plant," has two high-efficiency 13 MW nature gas turbines that create cool water which is then cycled back at a higher temperature, just to be cooled again. This waste heat recovery accounts for 95% of cooling on campus. Attached to a 3MW network of solar resources from carports and rooftop arrays, the system additionally allows for battery storage and water heating.

UCSD's microgrid additionally boasts a 2.8 MW fuel cell - the largest on any U.S. college campus. It uses methane from a regional wastewater treatment plant which is broken down to output electricity and waste heat, which is then used to power an absorption chiller that cools water eventually sent to a thermal storage tank. This provides about 7% of UCSD's total electrical needs - representing enough energy to power 2,800 homes.

With the growth of renewable resources on the microgrid, UCSD's Energy Research Park is bound to grow with it. It is already capable of storing 2.5 MW energy, capable of delivering a megawatt of power for up to five hours. This positions UCSD as ready to further implement even more renewable tech.

A unique feature of UCSD's microgrid is that it can 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. This gives UCSD the opportunity to give power to SDG&E in case of dire emergencies.

Outcomes

  1. An efficient solution that manages real-time demand while supplying and storing energy at a lower cost with less pollution than a conventional grid
  2. The grid generates so much electricity from solar PV at midday that it creates a negative price point of -2 cents per KWh - paying Arizona to take the electricity
  3. $12 million savings in annual energy costs, as a result of efficiency upgrades
  4. The ability to provide vital backup to the main electric grid (SDG&E) in emergencies
  5. Reduction of methane flared into the atmosphere, as fuel cells can dispose of the harmful gas in safer ways while also producing energy

Lessons Learned

  1. Because UCSD is subject to fewer ordinances than regulation utilities, the campus has used the microgrid to host a innovation incubator to test and demonstrate distributed energy solutions.

Something Unique

When wildfires erupted across San Diego, UCSD got an urgent call from SDG&E when they were forced to shut down a transmission line due to the fires. They were facing a critical power outage, so UCSD fed power back to the utility. What would normally be a 3MW importer of electricity became 10MW, averting a power shortage and crisis on the grid.

Who Should Consider?

Utilities looking for a greener, more efficient way to provide power in their communities.

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