a lithium battery system storing intermittent solar and wind energyBattery Energy Storage Systems (BESS) are essential as more renewable energy sources are added to the grid.  Renewable generation from solar and wind are intermittent by nature.  BESS, when integrated with a renewable and distributed energy supply, provides the power conditioning and regulation required for reliable connection to the grid. This conditioning and regulation is also referred to as grid support.  For this project, an 80 Mega Watt hour (MWh) BESS was installed to provide localized grid support. This BESS was designed to provide a maximum discharge rate of 20MW/h. The design also enables recharging the batteries during times when grid power is abundant. 


The project challenges included the need for long battery life, low fire risk battery design and reliable electrical and mechanical systems, resulting in a robust, long-term electrical grid support system. Nexus assisted the client in meeting additional design challenges to include an energy dispatch system with battery management capability, a self-contained HVAC system and other resiliency-critical auxiliary systems.  This design approach enables grid support at the sub-transmission level connection point.


Nexus provided technical expertise needed by the owner to define the project scope and develop contract parameters with the BESS provider.  Our knowledge of the facility, engineering creativity, controls skills and BESS experience were critical contributions to the Owner’s BESS project team.  In supporting this successful project, the Nexus Team provided:

  • Initial system analysis
  • Single line reviews
  • Review of construction documents and studies
  • Review of protection, control, and monitoring schemes

Client Name 

Western USA 


  • Conceptual Engineering and Design Input
  • Power System Analysis Input
  • Review of EPC deliverables
  • Electrical Expertise
  • Layouts, code, access and performance reviews
  • Construction Support


  • Client and BESS Contractor Design Standards
  • National and State Codes & Regs