resource adequacy
Today’s electric system is primarily composed of mechanical, largely thermal generators. Coal, gas, nuclear and hydro plants have predictable characteristics, from which utility planners have built expectations of performance and metrics that are used to ensure there is sufficient energy available to meet demand under widely varying conditions. This assurance is known as Resource Adequacy (RA). In its simplest form RA is determined by projecting expected demand for each hour of the year, then adding extra reserves to plan for unexpected events. Unexpected events can include loss of a generator or transmission segment, weather anomalies, etc.