Definition
Interruptible load is demand that an end-use customer makes available to its utility or load-serving entity for curtailment, via contract or tariff. In exchange for agreeing to reduce consumption when called, the customer receives a rate discount, bill credit, or capacity payment. Penalties may apply if the customer fails to curtail when instructed. Open Energy Information and FERC reporting define interruptible load (also called interruptible demand) in these terms.
How interruptible tariffs work
Under an interruptible or curtailable service tariff, the utility may reduce or interrupt service during system contingencies or peak periods. The customer accepts that risk in return for lower ongoing rates. Some programs notify the customer in advance; others, particularly emergency programs, allow the utility to act with little or no notice. Because the obligation is contractual, the load becomes a dispatchable reliability resource the operator can count on.
Who uses it
Interruptible programs have traditionally been offered to the largest industrial and commercial customers, whose sizable, flexible loads are worth metering and managing individually. Loads that can power down cleanly and quickly are especially well suited, since they can be shed without damage and restored when conditions ease. This makes interruptible arrangements a natural fit for deferrable industrial and compute operations.
Interruptible load is one contractual expression of broader demand response, and it interacts directly with curtailment when operators call on flexible consumers to reduce draw.
In Simple Terms
Interruptible load is demand that an end-use customer makes available to its utility or load-serving entity for curtailment, via contract or tariff. In exchange for…