Steffes GETS is an advance version of demand response (DR) that adds bi-directional control, monitoring, measurement, and verification to standard electric resistance water heaters (WHs).
Steffes GETS Dynamic Dispatch™ – Energy Management System
The GETS system of Dynamic Dispatch™ consists of an Energy Management System (EMS) interface, an aggregation server, and a host (or fleet) of end points. The EMS interface operates on a user-selectable time period up to as fast as once per second, with a default period of four seconds. When a new value is received, it is immediately transferred to the aggregation server which processes the power request immediately and makes the appropriate fleet control signal available to each of the end points.
Aggregation of these disperse assets gives the Steffes GETS system second to second precision control (0 to 100% charging) in real-time over fleets of WHs to add demand in times of over-generation in order to absorb excess power or reduce demand in times of under-generation to shed load. The aggregation (explained in more detail below) makes this fleet appear as a very fast-ramp virtual generator to the utility operator. In addition, this modular approach (versus the simple on / off action of Direct Load Control or DLC) effectively deals with Wind and Solar variability and volatility. As the share of renewable energy grows across the entire generation portfolio mix, the value of flexible load, managed in real-time, creates a very pliable and adaptable cost-effective tool for greater renewable integration.
- Utilities can perform arbitrage on the wholesale market price for electricity, charging the water heaters when the price is low and discharging them when the price is high, saving themselves and their customer’s money. This can be especially useful for Coops and Muni’s where the savings can be passed along directly to the customer.
- On a more advanced level, utilities can use GETS for frequency regulation or other ancillary services. Frequency regulation is the second-by-second matching of generation to the load. Depending on the market there can be significant revenue potential from frequency regulation. As more renewable resources like rooftop PV are added to the distribution system, net system wide generation will fluctuate more and more, and frequency regulation will be increasingly valuable.
There aren’t many resources that can supply the flexibility needed for this service – generating plants can’t generally respond quickly enough to track the signal, but this is something that energy storage can do very, very well.
The monetary value of frequency response depends on the interconnection where the signal comes from. The PJM Interconnection puts a much higher price on frequency regulation than most other RTOs or ISOs, thus making the financial incentive for GETS much higher in its territory.