All three systems were
built in response to the CPUC’s
order to Southern California investor-owned utilities
to fast-track energy storage in
order to provide better regional energy reliability.
The lithium-ion battery
projects are balancing renewable generation so that local
stored energy resources can
be tapped based on regional
electrical demand. The projects are installed in areas to
help mitigate the threat of
electricity service interruptions to critical load areas.
The systems were developed, manufactured,
installed and commissioned
in about six months, thanks
to the developers, local utilities and municipalities helping expedite permits and grid
interconnection. The projects used both small and
large central storage inverters. All three projects utilized
Eaton grid connection switchgear and medium voltage
Tomorrow: Amsterdam ArenA
To Use Recycled Batteries
In November 2016, the
Amsterdam ArenA signed a
ten-year contract with The
Mobility House, Nissan and
Eaton to provide back-up
power from a mix of second-life and new batteries. This
system will be used for a host
Beyond Te Battery: Energy
Storage System Components
Regardless of the battery technology used, the electrical system
supporting large-scale energy storage projects looks largely the
same; grid-tied power conversion systems, electrical balance of
system equipment to connect to the utility grid or facility and
the controller that intelligently manages it.
Inverters play a crucial role in storage projects and provide
the direct interface with the batteries. The inverter charges
and discharges the batteries and also provides the expected
grid regulation functions, complying with appropriate power
quality requirements and supporting the grid during abnormal
conditions with high, low and frequency ride-through functions.
Much like in solar PV plants, large-scale storage projects use
either large central inverters or rely on many smaller inverters.
Typically, large storage inverters range from 500 to 2500 k W, are
mounted on a concrete pad or skid and are rated for the outdoors.
Smaller storage inverters range from 50 to 250 k W, are rated for
the indoors and installed on the foor or a rack.
The electrical solutions supporting energy storage include
everything from the AC and DC switching and protection
to medium-voltage transformers to step up voltage to the
utility level. Typically, the utility dictates the requirements for
switchgear and metering.
An energy storage system controller is the interface between
the battery management system (BMS) and the utility or
building control system and supports specifc application
requirements like frequency regulation, renewable frming,
load shifting, or demands made to the system.
Best practices for energy storage control systems dictate that
they are modular and scalable when designed for large-scale,
utility applications. Modularity is important so that the system
has the fexibility to expand its control to other forms of DERs. The
controller for the energy storage system typically needs the ability
to operate in both grid-connected and islanded modes. — JV