Gigawatthour

A gigawatt-hour (GWh) is a unit of energy that represents the amount of energy produced or consumed when a power of one gigawatt operates for one hour. It is commonly used to express large-scale energy production, consumption, and storage.

One gigawatt-hour equals 1,000,000 kilowatt-hours or 3.6 × 10^12 joules. In relation to other energy units, 1 GWh is the same as 0.001 terawatt-hours (TWh) and 3.6 terajoules (TJ). Because it is a unit of energy, it should be distinguished from power, which is measured in gigawatts (GW).

In practical terms, GWh is used to report grid-scale quantities such as electricity generation, demand over a period, and energy stored in facilities like pumped storage or large batteries. For example, a 1 GW power plant operating for one hour yields 1 GWh of energy; running for 24 hours yields 24 GWh. Large renewable projects or transmission systems are often described in GWh to reflect their output or consumption over days, months, or years.

GWh is a standard unit in electricity markets, planning, and reporting. It provides a convenient scale for comparing different energy sources and storage options and for estimating the energy implications of policy decisions.