The Solar PV Panels work based on the amount of light they receive from the Sun, and thus, shading and/or to a lesser extent cloud cover can result in the generation of less power.
If only one of the panels is shaded, the performance of all of them is liable to dropping. This is because all of the panels are connected in series, and a bottleneck is created, because of which the bypass diodes drop the power of the whole unit, as to protect the shaded cells from damage.
Moderate shading is likely to reduce the panel's capabilities by about 20%, although this can be as much as 40% if the shading is vast. With this in mind, sometimes in areas prone to shading, a smaller unit that doesn't get covered by shade can produce more than a bigger unit which gets slightly darkened. Our surveyors will talk over the best option for you upon your free site survey and installation of your panels.