The term peak makes its way into many solar panel explanations. After all, when you get a free savings report from the solar experts at Blue Raven Solar, we’ll discuss how your roof layout, average weather, and the way the earth tilts all factor into your peak hours for maximum solar energy generation. 

But what does peak hours mean? We talk in-depth about it in our blog Daily Peak Sun Hours and Your Home Solar Energy System. 

On the flip side, there’s another term to know when it comes to solar power and electricity generation: off-peak. 

The simple definition of off-peak hours is “the opposite of peak hours,” but there are two specific definitions associated.

Definition #1: Off-Peak Sunlight Hours

The hours during the day before and after daily peak sun hours.

This is the opposite of the detailed peak sun hours we discuss in the article linked above. Due to the earth’s axial tilt, our seasons change and the average sunlight hours vary across the year. Due to average weather conditions, sunlight hours may be more or less scarce in an area.

Peak sunlight hours—or the time solar panels receive maximum sunlight in a day—is usually between 10 a.m. and 4 p.m., though your exact situation may differ. The hours outside of the peak sun hour window are your off-peak sunlight hours. While your solar system continually generates energy when sunlight strikes the panels (even on a cloudy day), they will be a little less efficient at generating power during off-peak sunlight hours.

Definition #2: Off-Peak Electricity Hours

The hours during the day when electricity costs are less due to decreased demand in a community.

The other definition of off-peak is related to the electricity economy rather than the physical properties of the sun, earth, and weather. There are certain times of the day when a community’s electrical grid is under more intense stress and demand. When the majority of people return from work and use their appliances at home it is considered peak electricity hours. During the night and early morning hours when all the lights are off it is considered to be off-peak hours.

This has resulted in many utility companies changing the way they do business. To account for these highs and lows in energy use, many utility companies offer time-of-use electricity plans which coordinate with customers around these hours.

What is Time-of-Use Electricity?

When a whole community uses electricity, it creates an immense draw on the grid—the demand is greater. It’s basic economics: when the demand for electricity is higher, the cost of the supply of electricity is likewise higher.

During off-peak hours, the reverse is true. If you find yourself using more electricity in the off-peak hours, a time-of-use electricity plan can save you money.

Many of these plans include super off-peak hours to encourage electricity usage during hours when it is easier to generate and produce for the community as a whole. This is important because if everyone in a neighborhood draws on the grid all at once—beyond the ability of the utility company to provide—then a neighborhood may experience blackouts. On top of adjusting your rates to offer you a better deal depending on the hour of the day, time-of-use plans help to avoid these more extreme situations.

When are Off-Peak Electricity Hours?

You can generally expect off-peak demand hours to be from approximately 7 p.m. to 1 p.m. (the next day) in the summer months. Winter months sometimes see two off-peak periods in a day: 10 a.m. to 5 p.m. and 9 p.m. to 6 a.m. (the next day). However, it’s important to note these hours can vary by time zone and region.

Since off-peak electricity hours are determined by electricity supply and demand, there isn’t a sure way of telling outside of your utility company’s specific plan. 

For example, Duke Energy in North Carolina lists its off-peak hours as: 

• Summer off-peak hours—between 8 p.m. and 11 a.m. 
• Winter off-peak hours—between 12 p.m. to 5 p.m. and 8 p.m. to 6 a.m.

Another utility company in North Carolina, Fayetteville Public Works Commission, lists their hours differently:

• Summer off-peak hours—between 7 p.m. and 3 p.m.
• Winter off-peak hours—between 6 p.m. and 10 a.m.

Both utility companies list these hours for Monday through Friday only, and as you can see, each plan has its own variations. It is important for solar panel owners to understand their utility company’s designated off-peak hours to take advantage of electricity savings.

How Do Off-Peak Hours Affect Solar Panel Owners?

Homeowners can use off-peak hours in a number of ways to maximize the savings from their solar investment.

Solar Power Offsetting Peak Hours

Your peak sunlight hours and peak electricity hours may overlap at certain times. This means you’re unlikely to need additional electricity—above what your solar panels can produce—from the utility grid during the hours when it is most expensive.

Depending on your roof space, the size of your solar system, and how much sun you can expect in your area, solar panels can help offset most of the increased costs of peak hours. When the sun goes down and your solar panels stop generating electricity, you can rest easy knowing you’re paying off-peak rates.

Battery Storage and Solar

Solar system owners may also invest in home storage solutions like batteries which allow you to save more. With the right sunlight and solar production, any potential excess—as you avoid electricity use during peak hours—can instead be stored on your property for use later.

When the sun goes down, you can pull power from your batteries. If they’re charged enough, you can go through the night without drawing from the utility grid at all.

Another tactic is to use batteries or other home storage solutions to supplement your power usage during peak hours. Doing so helps you use less power during the most expensive times of the day.

Solar Panel Alternative Time-of-Use Plans

Solar panel ownership can open specific doors with regard to time-of-use plans. Depending on the utility company, they may offer you an alternative plan designed to work around your electricity production. We recommend you reach out to your local utility company to learn about the details of these alternative plans and if they offer them.

Using Off-Peak Hours to Maximize Solar Benefits

If you have a solar system, you’ll want to consider both definitions of off-peak hours. Both sunlight off-peak hours and electricity off-peak hours are important to maximizing your investment as you have more tools than most utility customers to adjust your power usage habits.

Understanding these definitions can empower you to organize your electricity usage to help reduce your draw from the grid and develop a cost-saving strategy. By altering your power usage habits and leveraging your solar system’s strengths, you can keep most of your usage from the utility company in the off-peak or super off-peak hours to maximize monthly savings.

If you’re thinking about making the switch to solar and wondering what it could save you, our team can walk you through the basics and provide a free savings estimate.