Case Study 5
University Microgrid.
Project Issues
Aged infrastructure for existing heat and cooling central plant
Significant sustainability goals for the University
No extra funding available
Relatively large, spread-out campus
Good regulatory environment for solar
Relatively stable demand charges
Customer-Specific Solution
4.5 MW CHP system providing base load power and process thermal energy
3.5 MW rooftop solar array which provides almost complete coverage of the campus roofs (with the exception of historical buildings) and parking lots
Battery system to smooth supply coming from solar
No cost solution to University
CHP System replaces existing boiler/chiller set-up, takes up deferred maintenance, upgrades heating/cooling systems, off-sets annual O&M, results in significant capital and operational savings
Significant portion of solar array is interconnected as separate community solar gardens so that University can serve the local community by becoming a host for solar power not normally available to neighbors
Lessons Derived:
This campus project demonstrates a classic “microgrid” as generally thought of in the energy community. A single customer (the University) with multiple load points (dorms, athletic facilities, classrooms) and a single central plant can integrate many layers of technology to better serve the target community. In this case, the strategy employed benefits both the existing campus and the wider community as a whole.
The original request was for the export of power and thermal energy directly to neighboring buildings, but current utility constraints in franchise rights would not allow for the export of power. By hosting two community solar gardens, and exporting the output through different feeder circuits, we were able to accomplish the community goal, add additional sustainability metrics, and reduce the interconnection complexity of the project. The University is offsetting approximately $10 million in capital expenditures and the added energy generation on site is reducing operating expenditures by over $1 million annually.