UMass Amherst Electrical Microgrid Services

For over a decade, CHA has supported the development of a microgrid on the University of Massachusetts (UMass) Amherst campus. Originally contracted to improve the operation and reliability of their new cogeneration facilities, the relationship quickly grew to include expanded evaluations, system hardening, improvements, and expansion efforts.

CHA identified several items contributing to instability during grid-parallel operation of UMass’s 16MW combustion gas turbine and back pressure steam turbine plant. A major factor was the weakness of the local campus medium-voltage (MV) distribution system. CHA recommended and facilitated a switch from MV distribution service to a high-voltage (HV) transmission level service to remedy this. By adopting an HV transmission approach, service interruptions and perturbations became much less frequent, and the available power capacity and robustness of the supply were greatly enhanced. CHA supported UMass in their case for financial and technical support from the local utility to facilitate the change. Subsequently, CHA provided detailed design, construction, and ISO New England interconnection support of a new 100MVA Tillson transmission substation.

Distributed energy resources (DERs) are a key part of the UMASS power generation mix. CHA provided electrical design support that included interconnection, protection, and coordination to install approximately 5MW of solar PV. The systems were installed on multiple buildings and two large parking lot canopies. A power purchase agreement (PPA) was used to finance the project. The PPA required maximized use of the PV assets. CHA designed a unique control system that selectively disables certain sections of the parking lot PV arrays when campus load falls below the available generation capacity to support both the PPA and the campus’ minimum power import interconnection requirement. The parking canopy arrays connect directly to the campus 13.8kV medium voltage distribution system.

CHA provided electrical design, interconnection, protection, and coordination for a 1MW/4MWh battery energy storage system (BESS) to enhance the campus microgrid resiliency. The BESS will decrease the campus electric demand, reducing utility costs during peak load periods. The BESS will recharge during times of excess generation. The project is expected to have a simple payback of fewer than five years.