Written for somebody with no background. By the end you will understand what a module does, why it produces more in the cold, and what the numbers on a datasheet mean.
There is one physical effect at the bottom of all of this, and it is simpler than it is usually made to sound.
A solar cell is two layers of silicon treated so that one has a slight surplus of electrons and the other a slight shortage. Where they meet, a built-in electric field forms. When light hits the silicon, a photon with enough energy knocks an electron loose. The field pushes that electron in one particular direction rather than letting it wander back. Connect a wire between the two sides and the electrons flow through it. That flow is the current.
Two consequences worth holding on to. The current depends on how much light arrives, because more photons means more freed electrons. And the voltage depends on temperature, because heat makes the semiconductor leakier and the field less effective at holding the separation.
This surprises everybody. A module's voltage rises as it gets colder, so a clear cold day produces more power per unit of light than a hot one. Canadian winters are good for panel performance; what they are bad for is snow cover and short days.
It is also the single most important fact for anybody designing a system, because voltage that rises in the cold can rise past what the equipment downstream can accept. That is not a theoretical concern — it is the commonest expensive design error in PV. The arithmetic, worked →
One cell produces about half a volt, which is useless on its own. Cells are wired in series into a module — voltages add, so sixty-odd cells give you something in the tens of volts. Modules are wired in series into a string, adding voltage again, up to hundreds of volts. Strings are wired in parallel, which adds current instead of voltage. The whole collection is the array.
A series circuit matters for a reason that is not obvious: in series, the current is the same everywhere, so the worst module in a string limits the whole string. One shaded panel can pull down the rest, which is why shading assessment is not a formality and why module-level electronics exist.
The array produces direct current and buildings run on alternating current, so an inverter converts it. It does a second job as well: continuously hunting for the voltage at which the array delivers most power, which shifts with light and temperature all day. That is maximum power point tracking, and it is most of what makes a modern inverter worth its price.
From the inverter the power goes into the building's electrical panel. It supplies whatever is running at that moment; any surplus flows out to the grid. Under net metering that surplus earns a credit against what you draw later, which is how a system that produces at midday pays for consumption in the evening.
Not the panels. Modules are typically warranted for decades and degrade slowly and predictably. What fails is connections, inverters, and anything to do with water getting into something it should not. Which is why installation quality matters more to a system's lifetime than the brand on the module.
If this was interesting rather than tedious, that is a useful signal. What actually happens on an installation → · The jobs in this industry →
Yes, and more efficiently per unit of light, because the cold raises voltage. The limits are snow cover and short days, not the cold itself.
Yes, at reduced output. Diffuse light still produces current, just less of it.
Modules commonly carry long performance warranties and degrade slowly. Inverters and connections are the shorter-lived parts of a system.
In a series string the current is the same everywhere, so the worst-performing module limits the whole string. That is why shading assessment matters and why module-level electronics exist.
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