A Flex Alert is a call for consumers to voluntarily conserve electricity when there is an anticipated shortage of energy supply, especially if the grid operator needs to use reserves to maintain grid integrity. When consumers reduce electricity use during a Flex Alert, it can prevent more dire emergency measures, including rotating power outages.

A Flex Alert is typically issued in the summer when extremely hot weather drives up electricity use, making the available power supply scarce. This usually happens in the evening hours when renewable energy resources are no longer available, but temperatures remain high and consumers are returning home and switching on air conditioners, lights, and appliances.