Ecoult Grid Energy Storage and PJM Interconnection

(Pennsylvania, United States)


Ecoult implemented a grid scale energy storage system which provides 3 MW of regulation services on the grid of PJM Interconnection: the largest of 10 Regional Transmission Organizations (RTOs)/Independent System Operators (ISOs) in the United States. The system is also used for peak demand management.

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UltraBattery has been responding to PJM’s multi-megawatt demands second by second, month after month, year after year.

Client Challenge

With renewable portfolio standards coming into effect, the large-scale integration of intermittent wind and solar generation will affect the physical operation of the modern grid, resulting in an increasing need for regulation services.

Regulation services are necessary to provide fine tuning in real time for the network to match supply and demand and to that end keep a constant frequency. The energy store responds to a signal provided from the market operator, PJM.

The objective of the PJM energy storage project is to demonstrate the outperformance of the UBer (UltraBattery® Energy Resource) in the provision of regulation services. The fast-responding UltraBattery® technology can manage regulation services more efficiently. It is faster, more accurate, cheaper, and cleaner than the incumbent gas peakers often used for regulation services. The UBer is therefore able to displace fossil fuel generation methods in the provision of regulation services and to complement fossil fuel generation in the provision of other ancillary services.

Solution Provided

The Ecoult 3 MW UBer grid scale energy storage system has been successfully installed on the grid of PJM Interconnection. It is implemented both in a building and in a containerized format, to demonstrate flexibility in approach for prospective adopters. It uses four strings of UltraBattery® cells and connects to the grid from inside the East Penn Manufacturing site in Lyon Station, Pennsylvania.

The project provides continuous frequency regulation services bidding into the open market on PJM. The system is responding to PJM’s fast response signal.

The graph below shows the signal received from PJM and how accurately the frequency regulation services system responds to the PJM signal.

PJM Regulation Services Signal
PJM Regulation Services Signal

In providing frequency regulation services, the batteries roam in approximately a 10-15% Partial State of Charge (PSoC) band. Ecoult has implemented an application that follows the PJM signal and maintains the State of Charge. The below graph shows the four strings being maintained in very tight alignment.

PJM Regulation Services String State of Charge
PJM Regulation Services String State of Charge

The frequency regulation services system tracks the string voltage and the individual voltage of the cells. These are maintained in conservative bands, but to extend longevity, Ecoult is currently implementing additional optimizations to achieve even tighter ranges. The below graph shows the four strings in very close alignment.

PJM Regulation Services String Voltage
PJM Regulation Services String Voltage

Ecoult has a proven track record of successfully implementing and deploying the UltraBattery® technology globally in several grid scale energy storage projects for solar and wind smoothing, energy shifting and frequency regulation services.