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STC-1000 Storage Transaction Controller

The UtiliCell STC-1000 is a Storage Transaction Controller (STC) centered at the heart of any electric grid energy storage systems. Implementing our proprietary Grid-TRONIX™ Control System Architecture and EnergyWatch™ Software Suite, the STC-1000 provides smart gird intelligence for the control and deployment of energy storage. The unit programs and controls the load side AC power and energy, the DC power and energy through the battery, while having the ability to couple and bridge in other sources such as PV or Wind. The STC-1000 is populated with a variety of expansion modules for additional IO, processing and control capabilities. The STC-1000 is located in Control Cabinet of the EnergyVAULT™.

Product Specifications

STC-1000 Specifications
Energy Storage Capacity AC 250 KW-Hours with no upper Limit; 2MW-Hour is a typical size
System Power Capacity AC Maximum 250 KW with no upper Limit; 1MW AC is a typical output power
250 KW with no upper Limit; 1MW AC is a typical output power 85,000 MTBF
CPU / GHz / OS / Bus / Ext. Video Intel / 3.2 GHz / QNX / PCI-Express / VGA and HDMI
Power Requirements 115 VAC @ 3 Amps , 300 Watts AC
Typical Round Trip AC to AC Efficiency 87% measured as AC in to DC, battery, then DC to AC out.
Frequency Regulation 59.995 to 60 HZ via NIST, WWV, SCADA, master or slave sync
Mechanical Specifications
Enclosure Type & Mounting IEC - Rack Mount Enclosure, 19” – 4U
Unit Weight / Shipping Weight 46 Lbs
Dimensions (L x H x W) 4 7” Height {4U} x 19” Wide + 20” Deep


The STC-1000 is a hardened programmable logic controller, or storage abstraction layer and logical interface standard or “SALLIE” that broadly yet uniformly defines all hardware, software and controls within a storage system, plus everything external as well that affects the storage transaction or sequencing charge/discharge/lockout cycle, either locally or remotely. In real-time the STC-1000 aggregates all signals from an array of sensor inputs and control outputs, tying together all of the elements of advanced storage: the load, energy supply, power control system (PCS), the batteries, and battery management system (BMS), becoming the top layer of intelligence.


  • MODBUS, PCI-Express Adapter Card
  • USB - [6] Six Internal Ports USB v3.0
  • Gig-E Ethernet, PCI-Express Adapter Card
  • 100-BaseT Ethernet, – Internal, WI-FI – 802.11G /x /n internal
  • 100-BaseT Ethernet, PCI-Express Adapter Card
  • 8 Channel Input, 8 Channel Output Digital / Analog I/O Subsystem, PCI-Express Adapter Card
  • RS-232, RS-485 – One Internal
  • Protocols – TCP/IP, SCADA; OPTIONS – CANBUS, PCI-Express Adapter Card

Grid-TRONIX™ Control System Architecture

UtiliCELL’s Grid-TRONIX™ Control System Architecture. Our solution embodies system these elements:

  1. The actual physical storage medium or battery array, be it lithium, lead, metal/air, CAES or flow.
  2. The DC to AC inverter, discharging the battery as a form of distributed generation.
  3. The reciprocal or bi-directional AC to DC rectifier, storing energy by charging the battery array.
  4. The grid, utility, supply or generation upstream, be it wind or solar farm, or electric sub-station.
  5. The load, customer, transmission or distribution downstream that benefits from energy storage.

Control System Features and Services

The Grid-TRONIX™ Control System is critical to the management of the EnergyVAULT™ and customer assets. The main features and services which can be provided include the following:

  • Ramp Rate Control
  • Frequency Regulation
  • Peak Shaving (Peak Load Reduction)
  • Time Shifting
  • Load Leveling (Smoothing) and Following
  • Firming / Shaping
  • Curtailment Support
  • Power Leveling (Constant Power)
  • AGC
  • VAR Compensation / Voltage Support
  • Real-time Bidding (Capacity Firming)
  • Day-ahead bidding
  • FRRS or Reg D
  • Regulation Up/Down
  • Spinning Reserve
  • Non-spin Reserve
  • Reserve Capacity
  • Responsive Reserve
  • Black Start
  • Constraint Relief
  • T&D Deferral
  • Res/Ind UPS
  • Micro Grid Power and VAR Support
  • Islanding Support
  • Power Quality & Reliability
  • Power Plant Hybridization

Many of these control features can be active at the same time. The controller can control any process that has a measurable output (Process Variable or PV), a known ideal value for that output (Setpoint or SP) and an input to the process (Manipulated Variable or MV) that will affect the relevant PV.

Example Controller Process and Manipulated Variables

Controller Process Variable (PV) Manipulated Variable (MV) Setpoint (SP)
Reserve Capacity System SOC P command 71%
AGC Response AGC Setpoint P command 0 MW to 36 MW; settable by ERCOT
Frequency Regulation Frequency @ 69 kV POI P command -36 MW to +36 MW
Ramp/Excursion Control Ramp Rate @ 69 kV POI P command 1 MW/min or 2 MW/min; dependent on time of day