Frequency Regulation

Frequency Regulation (or just “regulation”) ensures the balance of electricity supply and demand at all times, particularly over time frames from seconds to minutes. When supply exceeds demand the electric grid frequency increases and vice versa. It is an automatic change in active power output in response to a frequency change. It is required to maintain the frequency within statutory and operational limits.

The CAISO market has several participation models for providing Regulation, which are relevant to different storage technologies. A pumped storage plant would be operated similarly to a conventional generator, with the unit following the regulation signal around a dispatch operating point. Other types of storage technologies, such as batteries, are operated differently because they follow the signal up and down, and can use both charging and discharging modes without transition times, thus amplifying the regulating range. There are two market participation models for these resources: the non-generator resource model (NGR) and the NGR with regulation energy management (NGR-REM) model. In the NGR case, the resource operator manages state of charge through bids or self-management, and the resource can provide Regulation and other services; in the NGR-REM case, the CAISO manages state of charge, but the resource can only provide Regulation. Because the REM case disallows stacking services and requires no operational decision-making, it is not modeled in DER-VET.

1. Inputs
   1. 1. Energy Throughput (Up)

Tag	Key	Description
FR	eou	This represents the extra energy that will be discharged or less energy that will be charged for providing 1 kW of regulation up for 1 hour. In reality, this parameter varies hour to hour and location to location but is fixed in DER-VET.

1. 1. 1. Energy Throughput (Down)

Tag	Key	Description
FR	eod	This represents the extra energy that will be charged or less energy that will be discharged for providing 1 kW of regulation down for 1 hour. In reality, this parameter varies hour to hour and location to location but is fixed in DER-VET.

1. 1. 1. Growth

Tag	Key	Description
FR	growth	This input grows the applicable regulation price signal(s) in the timeseries input file, either FR Price ($/kW) or BOTH Reg Up Price ($/kW) AND Reg Down Price ($/kW)

1. 1. 1. Energy Price Growth

Tag	Key	Description
FR	energyprice_growth	This input grows the price of energy used to re-settle energy market transactions after the energy throughput due to providing regulation is considered. By default, this is the day ahead energy price timeseries input.

1. 1. 1. Combined Market

Tag	Key	Description
FR	CombinedMarket	This binary input distinguishes combined regulation markets (1), where regulation up is offered in equal quantity to regulation down always, and separate regulation markets (0), where regulation up can be offered independently from regulation down. When CombinedMarket=1, the amount of regulation up offered by the DERs is constrained to be equal to the amount of regulation down offered by the DERs.

1. 1. 1. Duration

Tag	Key	Description
FR	duration	This input sets the minimum continuous energy requirement for participating in regulation. I.e, to provide 1 kW of regulation up for 1 hour, you need the physical ability to increase your generation by that amount for the duration input. This is particularly relevant for energy limited resources like energy storage.

1. 1. 1. Regulation Up Timeseries Constraints

Tag	Key	Description
FR	u_ts_constraints	This binary input applies the Reg Up Min (kW) and Reg Up Max(kW) timeseries inputs as constraints in the optimization.

1. 1. 1. Regulation DownTimeseries Constraints

Tag	Key	Description
FR	d_ts_constraints	This binary input applies the Reg Down Min (kW) and Reg Down Max(kW) timeseries inputs as constraints in the optimization.