An electric meter measures electricity in two ways:
- kWh = kilowatt hours, which is a measure of consumption
- kW = kilowatts in 15-minute intervals, which is a measure of demand
A demand measure represents the amount of power the utility must generate to fulfill the customer’s power needs.
Kilowatt vs. Kilowatt hour
One 100-watt light bulb burning for 10 hours consumes 1,000 watt-hours or 1 kWh. The entire time the light bulb is on, it requires or “demands” 100 watts or 0.1 kW from the utility.
This means the utility must have 0.1 kW ready whenever a customer turns on a light.
Similarly, ten 100-watt light bulbs burning for one hour consume 1,000 watt-hours or 1kWh.
A different way to look at demand and consumption is with the scenario of filling a 5 gallon bucket with water.