A terawatt-hour (TWh) is a unit of energy that represents one trillion watt-hours. It is commonly used to measure large-scale energy production and consumption, such as that from power plants or entire countries. For context, one TWh is equivalent to the energy consumed by about 90,000 average American homes in a year. This measurement is crucial for understanding electricity generation from sources like solar energy, wind power, and nuclear energy. By comparing TWh figures, policymakers and researchers can assess energy efficiency, plan for future energy needs, and evaluate the impact of renewable energy initiatives.