Beyond South: lower installed costs with east-west facing solar panels

Moustafa YoussefBlog

In the northern hemisphere the sun travels from east to west in a southernly direction and so aligning solar panels towards south allows them to capture the most amount of sunlight over the course of a day and year than any other direction. However because east-west facing solar panels are pointing in two different directions they provide a unique feature that allows for lower installed and/or levelized costs.

As shown below, solar modules pointing east and west peak before and after solar noon. More energy is produced as the sun rises in the sky, increases in intensity, and points closer in the direction of a solar panel. So for example a five kilowatt solar array facing south at a low tilt can peak around 4.8kW by 1pm, but a 5kW array facing south-east (45 degrees to the east of south) might peak by 1130am and a south west array by 3pm.

east and west solar arrays peak before and after south arrays

east and west solar arrays peak before and after south arrays

The point being is that a single south facing solar array will peak once but an input composed of two solar arrays facing east and west will peak twice or at least make the peak a lot wider than with south facing arrays. Knowing that both solar arrays are not going to peak simultaneously means that we may be able to add more input capacity to the inverter, allowing it to operate closer to its rated capacity and enhancing its efficiency.

more solar panels east-west solar arrays

combined east-west solar arrays can improve the capacity factor of a solar pv system because they stretch the peak ofproduction

The design advantage of east-west facing solar arrays

The outputs of east and west solar arrays allow for a more stable power output. The higher the tilts and the further from south the more bipolar their total daily output becomes. Flatter solar panels peak closer together because their direction is closer to the sun’s travel path.

effect of east-west facing solar arrays on output

solar production of east and west facing solar arrays with different tilts


Feel free to contact us to learn more about the potential of your east or west facing roofs.