Frequently Asked Questions: Glossary

Rolling Blackouts

Temporary interruption of electrical service. NYISO will implement rolling blackout only if and when New York's electrical system is unable to meet heavy peak demands because of an extreme deficiency in power supply. By temporarily disconnecting electrical circuits on a rotating basis, a majority of customers have power, inconvenience is minimized and a more serious widespread problem is averted. Each rotation is of a specific duration, usually no longer than a few hours, but it could take longer in some locations due to the manual nature of the operation.

Load Shedding

A purposeful, immediate response in electric service by the NYISO to a block of customers because demand for electricity has outstripped supply. Load shedding has never occurred in New York.

Voltage Reduction

If, after the other steps to manage capacity have been taken, the demand for electricity continues to exceed generating capacity, the electric utility can reduce voltage by five percent. This reduction essentially stretches out the available supply of electricity to all customers. It is rarely noticed by customers but may affect sensitive electronic equipment.