In electrical power engineering, “residual load” refers to the demand for electrical power (the “load”) in a power grid after eliminating the share of fluctuating feed-in from supply-dependent generators such as wind farms and photovoltaic plants. The residual load thus represents the demand that must be met by the available, dispatchable power plants (such as storage power plants and thermal power plants). If the available power plant output is too low, the uncovered load quantities can lead to a (power) failure on the consumer side in extreme cases.
The residual load depends among other things on the size of the area under consideration, as heavy regional fluctuations are balanced over larger areas. To enable such load balancing across wide areas, it will be necessary to expand the power grid as the use of renewable energies increases. Improving storage technologies can also help with load balancing. In addition to central pumped storage power plants, battery storage units for consumers are now being used to an increasing degree.