Megawatt-hour (MWh)

Metric (SI)Current unit

1,000 kilowatt-hours. Used for power-plant output and wholesale electricity trading.

1 megawatt-hour = 3,600,000,000 joules (exactly).

About the megawatt-hour

A megawatt-hour is a thousand kilowatt-hours, and it is where electricity stops being a household quantity and becomes an industrial one. It is the energy of a 1 MW load running for an hour, equal to 3.6 GJ, and it is used for metering large industrial customers and for the output of power plants.

The average US household used 893 kWh a month in 2020, so one megawatt-hour is a little more than a month of an ordinary home's electricity. Scaled up further, sustaining about 114 MW for a full year amounts to one terawatt-hour, the unit used for national generation figures.

Indian usage gives a neat link: a million of what Indians call units, meaning kilowatt-hours, is a gigawatt-hour, which is 1,000 MWh. Wholesale deals, plant ratings and grid statistics are typically quoted at this scale because the numbers stay readable.

Sources: Wikipedia: Kilowatt-hour; Wikipedia: Watt-hour; Wikipedia: Orders of magnitude (energy)

Megawatt-hour conversion chart

1 megawatt-hour expressed in every other energy unit:

More Metric (SI) units

• joule (energy)
• kilojoule (energy)
• megajoule (energy)
• gigajoule (energy)
• millijoule (energy)
• watt-hour (energy)
• kilowatt-hour (energy)
• tonne of oil equivalent (energy)
• meter (length)
• kilometer (length)
• centimeter (length)
• millimeter (length)
• micrometer (length)
• nanometer (length)
• picometer (length)
• decimeter (length)

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