Solar Power Systems

Solar panels with identical specifications can have a different electricity output, depending on how much sunlight reaches their photovoltaic cells. Before installing solar panels on any home or business, finding the ideal placement is a very important design decision. There are two important requirements:

• Ideally, solar panels should be installed in areas that never get shading. When this is not possible, they should be located on the rooftop or ground areas that will get the least possible shading throughout the year.
• Solar panels should also be positioned for maximum productivity. Their tilt angle and east-west orientation (azimuth angle) should allow the highest possible solar radiation on their surface, which translates into maximum savings.

Ground-mounted solar systems offer more flexibility during installation since their racking structure can have any tilt or orientation. Roof-mounted solar systems offer less flexibility since their possible orientations are limited by roof geometry and topology.

Solar engineers use advanced design software such as PVsyst, which can simulate the sun’s position in the sky throughout the year. This way, they can find the ideal placement for solar panels in any part of the world. When the optimal placement is not possible due to roof geometry or other site conditions, they can determine the second-best option that is feasible.

Solar design software can also simulate the shadows cast by surrounding obstacles such as trees and buildings. Based on the simulation of the sun’s movement, design software can determine how shadows will behave during the day and throughout the seasons. Using this information, the optimal areas for solar panels can be identified.

Solar Panel Positioning: The Effect of Geographic Location

The sun’s position in the sky at a given time of the year depends on your geographic location. In northern hemisphere countries like the US and Canada, most sunshine comes from the southern portion of the sky. This means that solar panels should be tilted south to maximize the amount of sunlight reaching their surface.

A north-facing solar panel will still generate electricity because it gets indirect sunlight, but it will not reach the highest possible output.

The opposite applies for southern hemisphere countries: solar panels should be tilted north, since most sunlight comes from that direction. For example, you would notice this if you visited Australia, one of the leading solar countries in the southern hemisphere.

As you move farther to the north or south, the sun’s position in the sky is lower at a given time of the year, and the optimal tilt angle for solar panels increases.

For example, California and Alaska are both located in North America, but the sun is much lower in the sky in Alaska. If you compare pictures of solar arrays in both locations, you will notice that the tilt angle is higher close to the north pole.

Finally, in countries close to the equator, the ideal placement for solar panels is facing upward. This maximizes the incident sunlight since the sun tends to be high in the sky throughout the year. This is very convenient in commercial buildings with large and flat roofs, since there is no need for a tilted mounting structure.

Finding the Optimal Solar Panel Tilt with the Global Solar Atlas

You can use the Global Solar Atlas to check the solar resources available in any part of the world, and this includes the ideal tilt angle for photovoltaic panels. The Global Solar Atlas was developed by the World Bank and the International Finance Corporation (IFC), and using it is very simple:

• Find your location by dragging and zooming the map provided by the Atlas and click.
• Alternatively, you can simply input your coordinates on the search bar.

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