Megawatts

Megawatt (MW) is a unit of power equal to 1,000,000 watts. In the International System of Units, a watt denotes the rate at which energy is transferred, so a megawatt represents a large instantaneous power level used to describe electricity generation and consumption.

In electricity, MW is commonly used to describe the capacity of power plants, the output of generators, or the total capability of a grid asset. Electrical output is often noted as MW_e; MW_t is used for thermal power measurements where heat is the primary product. Smaller installations are typically described in kilowatts (kW). A megawatt equals one million joules per second, and one hour of operation at 1 MW yields 1 megawatt-hour (MWh) of energy. Consequently, energy over longer periods is reported in MWh or gigawatt-hours (GWh).

Typical scales: a large wind or solar farm can range from tens to a few hundred MW; a modern natural gas combined-cycle plant may be several hundred MW; large nuclear and coal plants are commonly around 500 to 1,500 MW. Transmission and distribution equipment is often described by capacity in MW or MVA.

See also: Watt, Kilowatt-hour, Megawatt-hour, Gigawatt, Power (physics).