Reactive Power
The portion of electrical power that oscillates between source and load without doing useful work, measured in volt-amperes reactive (VAR). Required to maintain voltage levels on AC power systems.
Why It Matters
Modern smart inverters can provide reactive power support to the grid (IEEE 1547-2018), improving local voltage quality — a service utilities increasingly require or compensate.
Related Terms
Power Factor
The ratio of real power (kW) used to do work versus apparent power (kVA) drawn from the grid. A power factor below 1.0 means some energy is wasted as reactive power.
IEEE 1547
The national standard for interconnecting distributed energy resources (solar, battery, generators) with the electric grid, specifying voltage regulation, frequency response, and islanding detection requirements.