The speed and accuracy of the full-four quadrant DPR® allows it to participate in several technical support roles currently provided by fossil fuel generation, collectively referred to as Ancillary Services. The North American Electric Reliability Corporation (NERC) defines Ancillary Services as "those services necessary to support the transmission of capacity and energy from resources to loads while maintaining reliable operation of the Transmission Service Provider's transmission system, in accordance with good utility practice." Because without these services the grid would be much less reliable, their importance is shown through higher market values. The DPR can be installed to provide these lucrative services, with faster response than traditional generation and with fewer emissions.
The Midwest ISO (MISO), Pennsylvania/Jersey/Maryland Interconnection (PJM), New York ISO (NYISO), California ISO (CAISO), and New England ISO (ISO-NE) are all actively moving forward with modifying tariffs and/or rules that have previously limited the provision of such services to generators. These ISOs along with other progressive utilities are already utilizing energy storage systems to provide some or all of these Ancillary Services:
The unique sizing scheme of the DPR allows the customer to add more energy storage (MWh) and act as a responsive supply resource for prolonged periods of time via Automatic Generator Control (AGC).
Frequency Response (Primary Control)
Like generator droop response and turbine-generator rotating inertia, the DPR can actively correct frequency deviations automatically in real-time with power injections and withdraws following major electrical disturbances, as well as address less severe frequency deviations due to normal grid operations throughout the course of each day.
Frequency Regulation (Secondary Control)
The DPR can inject or withdraw larger amounts of power in response to AGC signals that raise or lower generator output. This service is typically procured by ISOs through competitive bids.
The DPR has the ability to supply and absorb reactive power (VARs) while simultaneously supplying or absorbing real power (Watts). This allows the system to maintain a target power factor while continuing to provide other functions that require real power management.
The DPR can act as a back-up power reserve by providing power when the grid experiences black-outs. The blinkless transfer from grid power to back-up power ensures reliability and improved power quality for critical loads.
In the event of an area-wide grid outage, the DPR can provide the power required to return baseload operating units to full capacity without relying on auxiliary power or the external transmission network.