El Centro Battery Energy Storage System

El Centro Battery Energy Storage System: The El Centro Battery Energy Storage System (BESS) reached its 8th anniversary of excellent operating record on the power grid. In 2015, ZG performed design, engineering, testing, and integration for the BESS interconnected to the IID 92kV transmission system. ZG provided owner-engineering services and assisted IID with the integration of the BESS into its energy management system (EMS). ZG also managed General Electric and Samsung as the equipment providers and project integrators.  Once the project reached commercial operation, ZG performed daily O&M services on the new system. The BESS went online in October 2016 and was one of the first battery systems interconnected to the California grid. The project was delivered on time and budget. IID’s BESS is located adjacent to the El Centro Generating Station within the City of El Centro, California. The BESS is designed as a high-power, low-energy resource with a rating of 20 MWh/33MVA. The BESS consists of the following components:

  • 30 separate battery banks made up of 16 strings of battery modules and components, containing 5,760 Samsung lithium-ion battery trays, associated battery management system controls, and monitoring equipment. The equipment is interconnected through a Modbus communication network. 
  • 30 GE Brilliance inverters rated at 1.25 MVA, up to 45 degrees centigrade, and 1.1 MVA, up to 55 degrees centigrade. The inverters had a rated power factor of +/-0.93. The inverters convert 480 volts AC to 600-800 volts DC when the batteries are charging from IID’s grid and 600-800 volts DC to 480 volts AC when the batteries are discharging energy into IID’s grid. 
  • 30 GE Prolec1.25 MVA isolation transformers that transform 480 volts AC to 34,500 volts. 
  • AC GE Mark VIe controllers are designed to receive communication from and send communication to IID’s EMS and GE’s SCADA system, translate and send/receive corresponding commands to and feedback from the Samsung battery management system.
  • 8 Trane 30-ton heat pumps and 4 Trane 25-ton air conditioning units with associated controls and dampers designed to maintain BESS building temperature, humidity, and pressure within operating limits. 
  • Four-zone fire suppression system designed by Schmidt utilizing 3-M’s NOVEC fire suppression agent, early warning VESDA Laser Plus smoke detectors, and secondary Kidde photoelectric smoke detectors.
  • 38.2 MVA, 34.5kV/92kV, Virginia Transformer was used to interconnect the BESS to IID’s 92 kV El Centro Switching Station. 34.5 kV on the BESS side and 92 kV on the IID grid side
  • BESS temperature-controlled building that stores the Samsung lithium-ion batteries while the inverters and transformers reside outside the BESS building on housekeeping support pads.