terawatt

Terawatt is a unit of power in the International System of Units (SI). It represents 10^12 watts, and the symbol is TW.

The tera- prefix denotes one trillion. A terawatt equals 1,000 gigawatts or 1,000,000 megawatts. This makes the terawatt a useful scale for describing very large-scale energy systems, well beyond the output of individual plants.

In practical terms, terawatts are used to describe global or national-scale power generation and demand. Individual modern power plants typically have capacities of around 1 gigawatt, so a terawatt corresponds to roughly the output of a thousand such plants. The concept appears in discussions of energy systems, capacity planning, and future scenarios for decarbonization and electricity supply.

Examples of scale and comparison: global electricity grids and energy strategies are often discussed in terawatts, while installed capacity for wind or solar is commonly measured in gigawatts. For perspective, the Sun delivers on the order of 174 petawatts (about 174,000 terawatts) of solar power to Earth at any moment, illustrating the vast difference between natural energy fluxes and human power usage. Terawatt-scale targets are frequently cited in planning for large-scale energy transitions and long-term capacity needs.

See also: gigawatt, petawatt, watt, SI prefixes.