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.