Requiring an experienced energy storage integrator, Half Moon Ventures turned to S&C Electric Company, which supplied complete engineering, procurement, Half Moon Ventures chose S&C because, instead of using a piecemeal approach that involved packaging batteries, inverters, and the balance of plant equipment together, S&C could deliver one cohesive solution. Half Moon Ventures preferred this approach because it would help eliminate scope gaps, reduce project expenses, and ensure the Minster Electrical Department received the best long-term value. As an EPC provider, a power-conversion system manufacturer, and a medium-voltage switching and protection expert, S&C was well positioned to tackle the sophisticated system.
S&C, with input from project stakeholders, selected a 7-MW/3-MWh energy storage system for the project. The system included S&C’s PureWave®SMS Storage Management System and an LG Chem lithium-ion (nickel manganese cobalt chemistry) battery system. S&C engineers designed an interconnect system that includes medium-voltage transformers and S&C switchgear to complement the energy storage system.
During the initial design phase, S&C engineers collaborated with project partners to integrate three customized services into the system design. As the primary service, S&C designed the system to provide frequency regulation in the PJM Frequency RegD Market. To accomplish this, the battery system was sized for frequent charging and discharging cycles.
S&C configured the PureWave SMS Control Platform to interface with PJM market interfacing software to enable the system to follow a signal from PJM, which is a regional transmission operator that coordinates the movement of wholesale electricity in 13 states and the District of Columbia. Based on grid conditions and market pricing, the system will generate revenue from either absorbing or dispatching energy.
As a secondary but congruent service to frequency regulation, S&C designed the system to provide var support to combat an occasional low power factor on the system. Initially, the Minster Electrical Department contemplated installing capacitor banks to rectify the issue. However, S&C’s PureWave SMS was instead used to provide power-factor correction concurrent with frequency regulation services. Simultaneously with a full charge or discharge, the system will provide 5.25 Mvar of power factor, both capacitive and inductive. This eliminated the need to install approximately $350,000 of var-compensation equipment.
The third service S&C built into the design was demand response for peak-load contribution charge reduction. At the end of each year, PJM looks at the five highest two-hour peak load periods across its entire territory. PJM then assesses a peak-load contribution charge to connected utility entities for
the load drawn during this time. To reduce this charge, the energy storage system software was designed to predict when these peaks would occur. During this period, approximately 10 times per year, the system will switch from providing frequency-regulation services to demand response services to consequently help reduce the charge.
After S&C fully designed and manufactured the system, S&C performed comprehensive Factory Acceptance Testing at its facility in Franklin, Wisconsin. S&C engineers performed tests and simulated real- world scenarios to ensure critical system-control components integrated together correctly. This proactive testing helped to reduce commissioning time in the field and, more importantly, ensured the seamless integration of complex system components.
The modular, containerized system design allowed for an easy installation. The power conversion system and battery system arrived preassembled with the necessary control and support systems installed. S&C used medium-voltage transformers, three 12.47- kV S&C PMH Pad-Mounted Switchgear units, and an S&C IntelliRupter® PulseCloser® Fault Interrupter to connect the energy storage system to the grid. This cohesive solution drastically simplified the project for partners Half Moon Ventures and the Minster Electrical Department.