Demand is the rate at which a member uses electric energy. A kW is 1000watts, and a kWh represents a 1kW used over 1 hour. Two members can use the same amount of energy, but one might use it slowly (for example, 1kW over the course of an hour) and the other much faster (for example, 1kW in 15 minutes). The first member put 1 kW of demand on our system; the second put 4 kW of demand, since they used the energy 4 times faster. 




What is the difference between Energy Consumption and Energy Demand?

A Car's speedometer is like the demand meter and the odometer is like a consumption meter.  Two cars could travel the same 100 mile road, one at 10 miles per hour for 10 hours and the other at 100 miles per hour for 1 hour.  It takes a much more capable and expensive engine to power the car at 100 miles per hour than the one going only 10 mph.   So, in this example consumption (kWh) is the distance traveled in a specific timeframe and demand (kW) is the speed at which that distance was traveled.


Car illustration

To fill a bucket with water, one can use an inexpensive hose connection that provides 1 gallon of water per minute, or one can use a more expensive large faucet that provides 5 gallons per minute. The flow rate is equivalent to demand, and the amount of water in the bucket is equivalent to consumption. Each bucket has the same amount of water, but one was filled 5 times faster. This is like two members using the same number of kWh, but putting different demands on the system.

Demand Water Bucket image