Solar Array

A solar array is a group of photovoltaic panels - flat glass-fronted modules that produce an electric current whenever light falls on them - wired together with the controls that turn what they make into power a building can use. It is how a site gets electricity without a line run to it, which matters most where extending that line costs more than generating on the spot. Almost everything else that runs on electricity, from a pump to a freezer to a lamp, ends up depending on it. The high-voltage wiring and controls are licensed-electrician work.

Shade is its worst enemy, and worse than it looks. Panels are wired in a chain, so a shadow over one corner drags the whole string down instead of the fraction it covers, and a tenth of an array in shadow can halve what it makes. That puts an array in conflict with anything planted or built to cast shade, and it has to be settled when the layout is drawn, because a tree planted for shade reaches the panels years later and the only remedy is to fell it. Panels also make power only while the sun is on them, so running anything after dark means a separate store of electricity, bought on its own shorter replacement cycle.

Two clocks run at once. Modules are warranted for 25 to 30 years, to the point where output has fallen about a fifth, while the electronics that convert what they make last roughly 10 to 15, so replacing those is scheduled work rather than a fault. On a roof the array is tied to the covering beneath it, since re-roofing means taking it off and putting it back, so panels fitted over a worn roof are paid for twice. Hail is the main physical threat to the glass, and dust, pollen, ash and leaves cut output, though where summers are wet the rain does that washing. The quiet failure is that none of this announces itself: a shaded, dirty or ageing array simply makes less, and the household adapts without noticing.