Solar Panel Azimuth Calculator


A solar panel azimuth angle is the horizontal angle observed clockwise north between the Sun and solar panels. In other words, it is the angle measured clockwise north from the local horizon of solar panels to the sun’s position on the horizontal plane. It is basically an angle that describes the position of the sun relative to solar panels and the direction from which sunlight reaches solar panels.

As with the optimal tilt angle of a solar panel, it varies daily and with the seasons. So, it is vital to the performance of a solar system since solar panels must be within the path of the sun to generate power.

As solar panel azimuth angle changes, the direction from which sunlight comes will change. This means that at some point, the sun’s rays may come from a direction away from the surface of solar panels. Of course, this would mean reduced or no solar power production.

With solar azimuth angle changing with time, it wouldn’t be efficient to adjust the direction of solar panels every time. Instead, we can work with an angle that would keep the panels in the path of sunlight for most of the year. This is where an optimal azimuth angle comes in.

What is the Optimal Azimuth Angle for Solar Panels?

There’s a general relationship between a location’s latitudinal hemisphere and its optimal solar azimuth angle.

Generally, locations in the Northern Hemisphere should face true south – meaning an azimuth angle of around 180°. Conversely, places in the Southern Hemisphere should face true north – an azimuth angle of around 0°.

Of course, the azimuth angle in the Northern Hemisphere is not always exactly southwards. Similarly, the azimuth angle in the Southern Hemisphere is not always exactly true north. There might be slight variations to the west or east, depending on factors such as weather.

What is Solar Elevation Angle?

Solar elevation angle is somewhat the vertical counterpart of solar azimuth angle. It is the vertical angle between the Sun’s position and the horizon of solar panels.

Solar elevation angle (also called solar zenith angle) is an indication of how high the sun is from a solar panel. Like solar azimuth angles, solar elevation angles vary throughout the day and throughout the year. In other words, the sun can be at higher or lower altitudes from solar panels in a location, depending on the time of day and season.

Since solar panels perform better when closer to the Sun, we’ll rather have the sun at lower altitudes always. But since this is not really possible, we need an optimal angle at which the panels will remain close enough to the Sun for most of the year.

Optimal solar panel elevation and azimuth angles ensure solar technology are proximal to and facing the sun more times than not. The goal is to ensure that the panels of such technology get as much sunlight as possible to generate solar power.

What is the Difference Between the Solar Azimuth Angle and the Solar Elevation Angle?

While both angles are measured relative to a local horizon, solar azimuth angle is the horizontal angle describing the position of the sun while elevation angle is a vertical angle describing the position of the sun.

Beyond the simple contrast, the primary importance of solar azimuth angle is to give details of the direction of sunlight. But for solar elevation angle, the primary significance is to describe the height of sun from a local horizon.

Solar elevation angle is measured between 0° and 90°. Contrarily, solar azimuth angle is measured between 0° and 360°.

When elevation angle is 0°, the Sun is along the horizon. Unfortunately, in this position solar panels may not receive a lot sunlight. Contrarily, when at 90°, the Sun is at the zenith and panels get a lot of sunlight. This is why solar elevation angle is also called solar zenith angle.

Unlike solar zenith angle, solar azimuth angles represent the direction of the sun. When azimuth angle is 0°, the sun is due north and the solar panel should face north. Then when the angle is 180°, the sun is southwards and the panel should face that direction.

An azimuth angle of 90° means the sun is due east. Then at 270°, it means the sun is due west.

How to Calculate Solar Panel Azimuth Angle

You can calculate solar azimuth angle using any of the following methods:

  • Magnetic Declination Map
  • The PVWatts® Calculator from the National Renewable Energy Laboratory (NREL)
  • Your Phone’s Compass
  • The National Oceanic and Atmospheric Administration (NOAA) Magnetic Declination Calculator

Magnetic Declination Map

Before we talk about how to use a magnetic declination map, we’ll define magnetic declination.

What is Magnetic Declination?

Magnetic declination is the angle between magnetic north (the north compasses point to) and true north.

So, how does it help us determine azimuth angle? Remember we said the azimuth angle of locations in the Northern Hemisphere is generally true south while that of the Southern Hemisphere is true north? Well, we can readily figure out true northern and southern poles when we know the magnetic declination value of our location.

How to Use a Magnetic Declination Map

Check for the Isogenic Line Closest to Your Location on the Map

Once you have your magnetic declination map, locate the closest isogenic line to your location on the map.

Look for the Magnetic Declination of the Isogenic Line

After choosing the closest isogenic line from the map, look for the magnetic declination value of that line. Take note of the sign of the value – check whether it is positive or negative.

The sign of the magnetic declination is vital as it tells us the relative direction of the true north or true south from magnetic north or magnetic south, respectively.

If the magnetic declination is positive, true north would be west of magnetic north while true south would be east of magnetic south. Contrarily, if negative, true north would be east of the north magnetic pole while true south would be west of the southern magnetic pole.

Face Your Solar Panels to True North or South According Your Latitudinal Hemisphere

If your magnetic declination is 20°, and you are in the Northern Hemisphere, you will face your solar panels true south. True south would be 20° east of magnetic south.

However, if you are in the Southern Hemisphere, face your solar panels true north: 20° west of the magnetic north.

PVWatts Calculator

The NREL’s PVWatts calculator considers historical weather data when estimating azimuth angle. So, in some ways, there’s a higher level of accuracy in its results.

How to Use the PVWatts Calcuator

Enter Your Location on the Calculator

Go to the PVWatts calculator page. In the “Get Started” search field, enter your home address. Then click on the “Go” button.

If you’ve entered the correct address, this should reflect on the map under the “Resource Data Map” section. But if the map is not showing the correct location, click on “Change Location” at the top of the page to adjust it.

Experiment With Different Azimuth Angle Values

Once you have the correct location on the map, click on “System Info” – the tab between “Resource Data” and “Results”.

When on the “System Info” page, you’ll see an azimuth angle “Azimuth (deg)” that is either 0° or 180°, depending on which hemisphere your location falls.

Alter the solar azimuth angle in different ways and each time, go to the “Results” tab to see the estimated energy production. Keep changing the angle until you get the highest energy production.

Find True North and Place Your Solar System According to the Azimuth Angle

Once you have your azimuth angle, find true north using a magnetic declination map or calculator. Then orientate your solar panel according to the azimuth angle.

The PVWatts calculator is not just for azimuth angle; you can use it to determine solar panel tilt angle too. So, while changing the azimuth angle to find your optimal azimuth angle, you may also experiment with the tilt angle.

Finding the optimal tilt angle and optimal azimuth angle would make the solar panel orientation better and easier.

Phone Compass

If you use a device that runs on iOS, your device’s compass might just be able to help you figure out true north or south, depending on your case.

1. On your iPhone, go to settings.

2. Scroll down to “Compass” and click on it.

3. Once in the “Compass” menu, click on “Location”.

4. From the “Allow Location Access” options, choose “While Using the App”

5. Go back one step to the “Compass” menu.

6. Click the toggle switch to activate “Use True North”

7. Close settings and open the Compass app.

8. Now, the Compass app will show your true north instead of your magnetic north.

9. Align your solar system based on your latitudinal hemisphere. If in the north, face the panels southwards. If in the south, make them face north.

NOAA Magnetic Declination Calculator

Besides a magnetic declination map and your phone’s compass, the NOAA magnetic declination calculator is another option for finding true north.

How to Use the NOAA MAgnetic Declination Calculator

1. Go to the NOAA magnetic declination calculator page.

2. Under the “Lookup Latitude/Longitude” fieldset, enter your location in the “Location” search bar and click on “Get & Add Lat/Lon”. Once you do that, the input fields of the “Calculate Declination” fieldset will automatically be filled with corresponding data about your location.

location field in lookup

3. Once that is done, click on “Calculate”

4. After clicking on “Calculate”, the calculator will return the current date and the magnetic declination of your location in a pop-up window.

azimuth declination information

5. The calculator shows declination value in degrees, minutes, and seconds. But you should convert that value to degrees only before you work with it.

6. Once you have your magnetic declination in degrees, use that value to determine true north from your magnetic north.

7. When you find true north, make your panels face true north or south, depending on your latitude.

What is Solar Panel Tilt Angle?

We’ve mentioned tilt angle a few times already, and it is about as vital to solar panel orientation as elevation and azimuth angles.

Solar panel tilt angle is the angle at which a solar array will get maximum irradiance from the sun. It is the angle between the solar array and the surface on which it is installed.

Like solar azimuth angle and solar zenith angle, solar tilt angle varies with time and seasons. But with tools like the NREL PVWatts calculator, a solar panel angle calculator, or solar angle chart, we can get an optimal angle that works most times.

When we have an optimal angle, we may choose to only adjust the panels’ tilt angle monthly or quarterly. Then again, we could leave the solar array fixed.

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