The University Area Joint Authority (UAJA) is continually searching for new ways to increase the sustainability of their operations. As such, they decided to install a 2.6-megawatt ground-based solar array that will produce enough energy to offset approximately 25 percent of its overall electric power requirements. Because electrical grids experience times when consumption exceeds production and vice versa, especially when using renewable sources, UAJA retained RETTEW to find a way to stabilize the system and provide reliable power.

RETTEW worked with UAJA to evaluate various types and suppliers of energy storage systems and determined a 1.5-megawatt battery energy storage system (BESS) is the best option to balance the difference between generation and demand. By storing the energy during times of low demand, the BESS can provide energy during times of peak demand. The BESS’s primary use is the modulation of regional grid frequency to prevent oscillations outside of the utilities requirements. With small injections of power from the BESS, or acceptance of power into the BESS at UAJA’s interconnection point, the BESS provides a source of revenue for UAJA by participating in the PJM Frequency Regulation Market. RETTEW anticipates the increased renewable energy use at the wastewater treatment plant will result in long-term savings of $2 million over 25 years.