Megawatthour

Megawatt-hour (MWh) is a unit of energy used to quantify the amount of electrical energy produced or consumed over a period. It expresses the total energy delivered by a source or used by a system. The term means one megawatt of power sustained for one hour. Since one megawatt equals 1,000 kilowatts and one hour equals 3,600 seconds, a megawatt-hour equals 1,000 kilowatt-hours or 3.6 × 10^9 joules. MWh is not an SI base unit but is a widely used energy unit in electricity engineering and markets.

The MWh is distinct from the unit of power, the megawatt (MW). A device rated at 1 MW produces energy at a rate of one megawatt; if it runs for one hour, it generates one MWh of energy. For conversions, 1 GWh equals 1,000 MWh, and 1 kWh equals 0.001 MWh. These relationships are common in discussions of generation, consumption, and storage at grid scale.

Uses and context: MWh is widely employed in electricity markets and planning to express energy production and consumption, pricing, and capacity. It is also used to specify energy storage capacity, with storage devices rated in MWh indicating how much energy can be released. In practice, MWh helps compare different energy sources, assess grid reliability, and inform decisions about generation mix, demand response, and storage deployments.