Energy use over a period of time.
Power = Work / Time
Joule (J)
The most fundamental measurement of energy. It is the energy
of 1 kilogram moving at one meter per second. A 100-watt bulb
has a flow of 100 joules per second.
Watt (W)
A measure of power equal to one joule per second. Watts are
the standard measurement for light bulbs. A 100-watt bulb consumes
100 watts of electrical power.
Watt-hour (Wh)
One watt of power supplied for one hour.
Kilowatt
(kW)
One thousand watts. 1 kilowatt can light 10 100-watt light
bulbs.
Kilowatt-hour (kWh)
One kilowatt of power supplied for one hour. A person’s
electric use in their home is measured in kilowatt-hours. For
example, a person living in a one-bedroom apartment uses about
250 kilowatt-hours per month.
Kilowatt-hours can be determined by multiplying
watts used by the number of hours and dividing by 1,000.
For example, if you use a 100-watt bulb for 5 hours each
day for 30 days, you have used 100 watts of power for
150 hours.
100 watts x 150 hours = 15,000 watt-hours of electrical
energy, or 15 kilowatt-hours
Megawatt (Mw)
1 million watts, or 1,000 kilowatts. 1 megawatt can light
10,000 100-watt light bulbs.
