We’ve all seen it in the movies, where extreme cold is used to shatter a lock or iron bar. This sensational display is exciting to watch, but can be a little misleading for those who wish to duplicate. For while there is a grain of truth to the science behind things becoming brittle when subjected to freezing temperatures, quite often, reality isn’t as dramatically rewarding as one might hope.
So what exactly is the truth when it comes to solar power? Do solar panels freeze in the winter?
While solar panels can be exposed to extreme cold, they will not freeze and become inoperative during the winter. Point of fact, the exact temperature where a solar panel would become brittle due to freezing is not likely to be encountered by any natural means. This is well proven as solar panels have been successfully employed in the cold of space for decades.
Even Alaska, which has some of the coldest winters on the planet, is now home to some very interesting solar projects.
What Is Freezing?
Wikipedia defines freezing as the point ‘where a liquid turns into a solid’. This is important to understand as solar panels contain no liquid – in other words, they are already in a solid state.
To get Crystalline silicon, one of the main components in solar cells, to achieve a liquid state, one would actually have to heat it up… a LOT!
The melting point for Crystalline silicon is actually 2577 degrees Fahrenheit (1414 C). Anything below this and the silicon returns to a solid state, which by definition implies that it is frozen.
And in case you were wondering, the aluminum housing which holds the silicon, actually has a melting point of 1221 degrees Fahrenheit (660 C). In other words, the metal housing would turn to a liquid long before the silicon ever would.
## Note ##
The exact melting/freezing temperatures for your solar panel will vary according to the composition of the silicon and aluminum.
Freezing Temperatures: Contraction And Expansion
People generally think of solids as unchanging. But this is an inaccurate assumption. Aluminum, for example, can actually expand and contract a fair amount according to ambient temperature.
For example, I have personally witnessed aluminum door handles (made for refrigerators) expand more than 1/32 of an inch after being taken out of the back of a truck that had been sitting outside in a Michigan winter and brought to Quality Control, which was temperature controlled at 72 degrees F.
So while solids are in fact rigid, that does not mean that they are unmoving.
As a general rule, the softer the material the more dramatic the change with regards to temperature. (This is why you might hear the term ‘heat treating’ for hardness).
Freezing And Brittleness
It’s worth noting that there is some logic to the thought of things becoming brittle when exposed to extreme cold. This is because the molecules that make up an item slow their natural movement in freezing conditions.
When this happens, the molecular bonds that may have been broken due to an external force (think of item flexing) are unable to reform completely/successfully.
The first signs of this occurrence are usually seen in the form of stress fractures but if negative conditions persist, the item will eventually shatter.
The idea that a solar panel would become brittle due to extreme cold is not completely without warrant. However, the severity of this temperature requirement pretty much rules out any sort of natural occurrence.
Even the tempered glass which makes up the protective coating on your solar panels is fairly resilient against freezing temperatures.
But that is not to say freezing winter temperatures can’t damage your panels. It is not unheard of for ice to put a lateral force on the panels, quite often causing the glass coating to fracture. This is usually the result of water (via melting snow) accumulating between the metal housing and the glass and then freezing overnight.
Aside from this rare but negative event, solar panels are perfectly adept at providing you power despite any winter freeze.
For more on this, please read: ‘Do Solar Panels Work In Winter?’