1. Energy is the capacity for doing work. Some common forms of energy are electrical, mechanical, and chemical. Symbol, W. Common units: joule, watt-hour, and kilowatt-hour.
See also, CONSERVATION OF ENERGY, KINETIC ENERGY, and POTENTIAL ENERGY.
2. It is the work performed by electric power. The unit used by utility companies is the kilowatt-hour (kWh), equal to the product Pt, where P is power in kilowatts and t is the period (hours) during which the power is used.