Load control is a measure utilities use to reduce demand on the electrical grid. When the load on the grid from consumers using electric devices rises, instead of increasing production to make more supply available, the utility cuts down on the load. There are a number of measures utilities can use to do this including ripple control, timed meters, incentive payments, or penalizing tariffs. Utilities may use a combination of these techniques to balance the load with the available supply.
In ripple control, the utility sends a signal that turns nonessential equipment off. Consumers can agree to participate in a voluntary load control program where they fit specialized devices to their electrical systems. The utility can shut off equipment when it is not in use, or when the owner has indicated that it is not critical for daily activities. Power to other equipment remains stable. This is an example of smart grid technology that relies on extensive monitoring and control of components of the grid to manage energy use.
Utilities can use load control when demand starts to peak, as for example in the summer when people run air conditioners on high to manage high temperatures. This creates a risk of overwhelming the grid and creating a blackout, which would lead to adverse conditions. With load control, the utility can spot the increase in the load, send a signal, and turn off devices that do not need to be on to bring the load back down. Participants in such programs receive a reduced rate for their electricity.
Timed meters can cycle power to an entire facility or to specific equipment on a schedule. Consumers can install these themselves, and may receive an incentive for activities like putting a water heater on a timer. The utility uses timers to encourage consumers to restrict energy use, and to shift energy use to off-peak hours. Time of use metering is another approach, where customers receive a special low rate for off-peak usage.
Incentive payments can allow for load control by rewarding consumers who reduce energy usage. These payments may be provided when companies install energy efficient equipment, or reduce their monthly use by a given percentage. Conversely, the utility can charge extra for use above baseline, estimated by averaging electrical use and comparing it to that of similar facilities or households, to create a penalty for high energy use. The punishment creates an incentive to stay at or below baseline to avoid the extra charges.