At AboutMechanics, we're committed to delivering accurate, trustworthy information. Our expert-authored content is rigorously fact-checked and sourced from credible authorities. Discover how we uphold the highest standards in providing you with reliable knowledge.

Learn more...

What is a Load Curve?

Jennifer Leigh
Jennifer Leigh

A load curve is a chart used by engineers and power producers to show how much electricity customers utilize during a given period of time. When looking at the graph, time usually is placed on the horizontal axis, and load is placed on the vertical axis. This data can be used to predict power trends, which allows an area to build and connect sufficient power generators for peak demand periods. Types of power generators vary depending on the resources in a geographic area. Load curves can be calculated in different ways depending on the needs of the electrical suppliers.

Daily, monthly and yearly load curves are used by power stations to determine the amount of generators needed. Daily load curves look at a 24-hour period of time to find the load requirements every half-hour or hour. A monthly curve records load changes during a one month time period versus the number of days recorded, and a yearly load curve establishes the variations in power requirements throughout one year based upon the monthly load variations. The highest point on a load curve is the maximum demand at a given point in time. The area under a curve is the amount of units that were generated during that period of time.

Load curves might distinguish power utilizing areas like street lights.
Load curves might distinguish power utilizing areas like street lights.

A load curve can also be calculated based on the types of power being utilized in a system. This type of graph breaks down the power distribution according to the electric demand technology being used. Graphs looking at each type of electric technology are much more data- and labor-intensive than those that do not break down things into such small segments, but they can be helpful because of increased accuracy. Load curves calculated using this method can also look at daily, yearly and monthly supplies for each type of technology. Curves are sometimes prepared that break down the different population segments utilizing power, such as commercial, residential, industrial, hospitals, street lights and entertainment.

Different power stations can be connected in different ways throughout the year in order to meet the demand for power in an area. Types of power generators include nuclear, steam, hydro and gas turbine. The most efficient power generators are used during the highest peak demand times for power, which is based on the information gleaned from the load curve. Engineers use complicated formulas to calculate the loads curves, which in turn determine which method of supplying power is best at a given point in time.

Discussion Comments


@Mammmood - I work for a software company that caters to electrical utilities. We have software that provides reports on the various electrical load outputs used across a range of criteria.

Honestly it’s one of the features of the software that makes it compelling for utilities to buy. They can also archive data generated by the reports so that they can produce historical trends of electrical load profiles across a ten year time period if they want.

With this information they can plan out how much infrastructure they need in their substations and so forth. If they can’t handle the excess surge in electrical demand, it increases the likelihood that they’ll have a fault somewhere down the line.


@golf07 - The load curve provides an excellent basis for a forecasting system that will enable you to know not only what your expected usage will be, but what your monthly utility bill will be as well.

Our utility company uses this information to provide a cost savings program for all its customers. Basically they offer a program where they ask you to pay a fixed cost each month, which represents the average of your utility payments for the year.

This enables you to budget and not be stuck with high utility bills for either the summer or winter months. We use the program and it’s proven to be quite accurate. Sometimes the utility will make a slight adjustment if we have a harsh winter or summer, but it’s only slight, and the payments are still affordable.


@golf07 - Do you have a thermostat that you can program to run during certain times of the day?

Our electric company has a similar incentive, and I have not signed up for it because I usually have my thermostat programmed pretty high during the day in the summer.

I have the thermostat set so my air conditioner will come on about 45 minutes before I get home. This way the house is cool when I get home, yet has not been running on high all day long.


Every year in late spring we get a letter from our power company. This mailing includes a sample of our load curve average from the previous summer months.

This mailing is sent out as an incentive for customers to enroll in a program they have every summer. Basically you are agreeing not to have your air conditioner on during peak times of the day in the hot summer months.

I don't have any idea how many people sign up for this incentive. They will take so much money off your utility bill for signing up for this program.

I understand their reasoning behind this, but have never yet participated in the program. You never know when you are going to have one of those extremely hot days. I don't want to come home from work and find out it is during a peak time and my house is really hot.

Post your comments
Forgot password?
    • Load curves might distinguish power utilizing areas like street lights.
      By: Pavlo Burdyak
      Load curves might distinguish power utilizing areas like street lights.