Ergs
An erg is a unit of energy defined as the work done by a force of one dyne exerted over a distance of one centimeter which is equivelent to 10-7 joules.
Kilowatt-hours
A kilowatt-hour (kWh) is the amount of energy when a power of one kilowatt (1,000 watts) is used continuously for one hour. Utility companies often bill consumers based on the number of kilowatt-hours consumed.