Enter the energy consumption and the time period to calculate the average demand over that period (kW = kWh ÷ h). In utility billing, maximum demand is typically the highest demand recorded over a defined demand interval (often 15 or 30 minutes), so you would calculate demand for each interval and take the maximum.
Demand (Interval Average) Formula
The following formula calculates the average electrical demand over a specified time period. To determine maximum demand for billing, utilities typically measure demand over a fixed interval (for example, 15 or 30 minutes) and the maximum demand is the highest interval-average demand during the billing period.
D = E / T
Variables:
- D is the average demand over the time period in kilowatts (kW)
- E is the total energy consumption in kilowatt-hours (kWh)
- T is the time period in hours (h)
To calculate the average demand over a time period, divide the total energy consumption by the time period.
What is Electrical Maximum Demand?
Electrical maximum demand refers to the highest level of electrical power demand recorded over a specific period. In many utility billing systems, it is measured as the highest average kW over a defined demand interval (commonly 15 or 30 minutes) during the billing period. It is a critical parameter for electrical utilities and consumers as it helps in determining the capacity requirements of electrical systems and infrastructure. Maximum demand is often measured in kilowatts (kW) and is used to ensure that electrical systems are designed to handle peak loads efficiently. It also plays a role in tariff structures and billing for commercial and industrial consumers.
How to Calculate Electrical Maximum Demand?
The following steps outline how to calculate the Electrical Maximum Demand.
- First, determine the energy consumption (E) in kilowatt-hours (kWh) for the period you are evaluating (ideally a single demand interval, such as 15 minutes).
- Next, determine the time period (T) in hours (h) for that same interval.
- Calculate the interval-average demand using the formula D = E / T.
- To find maximum demand over a longer span (such as a billing month), repeat for each interval and take the highest interval value.
- After inserting the values and calculating the result, check your answer with the calculator above.
Example Problem :
Use the following variables as an example problem to test your knowledge.
Total energy consumption (E) = 500 kWh
Time period (T) = 10 hours
The average demand over this 10-hour period is 50 kW (500 kWh ÷ 10 h). The true maximum demand during those 10 hours could be higher (or lower) depending on how the load varied within the period and on the utility’s demand interval.