Measurement
A gigawatt-hour (GWh) is 1,000 MWh (one billion watt-hours) of energy. This unit is used to describe massive energy production or consumption at the grid level. For example, a large solar power facility might generate several GWh of electricity over a year, and utilities often measure annual electricity sales or storage capacity in GWh. It provides a sense of scale for energy in national or regional contexts, as in “the city consumes 5,000 GWh of electricity per year.”