The gigawatt, unit of power
The gigawatt is a thousand million watts, that is a thousand megawatts. It is the unit in which power stations, national grids and interconnectors are counted, and it is far too large for anything a household owns.
It is the scale at which a country plans. The Three Gorges dam reached its full 22.5 gigawatts in 2012, when the last of its thirty-two main generators came online, making it the largest power station ever built. A modern nuclear reactor sits near 1.6 gigawatts, and the largest offshore wind turbines around 0.015, so a single gigawatt is about sixty-seven of them turning at once.
The gigawatt in other units
| 1 GW | 1,000,000,000 W |
| 1 GW | 1,000,000 kW |
| 1 GW | 1,000 MW |
| 1 GW | 1,341,022 hp |
| 1 GW | 1,359,622 PS |
| 1 GW | 3,412,141,633 BTU/h |
| 1 GW | 860,420,650 kcal/h |
| 1 GW | 1,000,000,000,000 mW |
| 1 GW | 737,562,149 ft·lbf/s |
Frequently asked questions
How many watts are in a gigawatt?
A thousand million, that is 10⁹, and a thousand megawatts. The step from megawatt to gigawatt is the step from one power station's turbine hall to a whole fleet of them.
What does one gigawatt actually supply?
It is roughly one large nuclear reactor, or sixty-seven offshore wind turbines of fifteen megawatts each turning at full output. Since wind and sun do not run continuously, comparing them by capacity alone always flatters the intermittent source.
Why do people quote 1.21 gigawatts?
Because of the 1985 film Back to the Future, in which the time machine needs exactly that. The figure has no engineering meaning, but it put the word gigawatt into everyday speech, which few units of power can claim.