Loss of load in an electrical grid is a term used to describe the situation when the available generation capacity is less than the system load.[1] Multiple probabilistic reliability indices for the generation systems are using loss of load in their definitions, with the more popular[2] being Loss of Load Probability (LOLP) that characterizes a probability of a loss of load occurring within a year.[1] Loss of load events are calculated before the mitigating actions (purchasing electricity from other systems, load shedding) are taken, so a loss of load does not necessarily cause a blackout.