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 the total energy used by a country in a year. One TWh is equivalent to the energy consumed by a million homes over a month. To put it in perspective, if a household uses about 1,000 kilowatt-hours (kWh) per month, it would take approximately 83,333 homes to consume one TWh in the same period. This measurement is crucial for understanding energy trends and planning for future energy needs in relation to sources like renewable energy and fossil fuels.