Solar panels are all the rage these days and for good reason. For environmentalist, solar panels reduce the emissions involved with carbon fuels. For those who are more monetarily motivated, it means getting electricity ‘on sale’ by buying in bulk at today’s prices, rather than paying the inflated prices of 10+ years from now.
But regardless of individual reasoning, the question for everyone is, ‘how do solar panels work?’
In the simplest of definitions, solar panels work on electron flow – flow which is triggered by the bombardment of photons present in sunlight.
While I’m sure this obvious to individuals with a background in advanced electronics, for the rest of us, this is about as clear as mud.
So let’s break it down into more understandable terms.
Solar Panels: What Is Electron Excitation?
Perhaps the easiest way to think of electron excitation in solar panels is to take what we know of the game of billiards.
Imagine those fifteen multi-colored balls on top of the pool table, resting comfortably and not moving. These represent the electrons present in solar cells.
Now imagine the solid white cue ball being slammed into those fifteen balls and we all know how things get ‘exciting’ and really start moving.
This is what happens when a photon that is present in sunlight, slams into solar cells; the electrons start moving.
The definition for this process is known as the photovoltaic effect and quite adeptly uses the term ‘excitation’.
Solar Panels: Channeling Electron Flow
Now that the electrons are excited and moving, it’s time to channel that movement. This is accomplished in two parts.
- First, by the ‘driving presence’ of a electrical field created by the inherent qualities of the materials used.
- Second, by the ‘easy flow’ electron conduits (small wires) that finger their way through the solar cell.
To put this in our billiards example, the ‘driving presence’ of our electrical field could be simulated by raising one end of the pool table. In this situation, the multi-colored billiard balls will naturally want to roll to the lowest end of the table.
In turn, the ‘easy flow’ electron conduits are represented by the pockets in the corners of the billiard table where the balls are allowed to simply drop away and escape all the ‘excitement’ that is happening on the table.
Solar Panels: Electron Work
A fundamental concept of virtually every field of science is the balancing of potentials. Whether it is hydraulics, pneumatics, aerodynamics or in this case electronics, there is an inherit need for things to balance out.
As the excited electrons in the solar cells move and channel their way away from the driving electrical field, an imbalance is created via an absence of electrons. (See electron holes)
This imbalance is the core concept of electron flow, which, when channeled through ‘easy flow’ electrical conduits (aka wires) is how we get electrical current. And it is this current that powers our electrical devices.
In order to visualize this, let’s consider our billiards table.
With some billiards tables, there are internal pathways (easy flow conduits) connected to the pockets that allow the billiards balls that have dropped off, to roll back to one side of the table. Once the ball is there, a player can retrieve it and place it back on the table for further play.
This is the same for solar panels.
In essence, excited electrons make their way back around and are returned … for additional photons – present in sunlight – to knock them into an excited state, whereby the process is repeated.
Solar Panels: Step By Step
So to recap, here is a simplified process of how solar panels produce electricity.
- Step 1 – A photon present in sunlight strikes the relatively relaxed electrons present in the solar cell. This contact ‘excites’ the electrons causing them to move (think cue ball striking racked billiards balls).
- Step 2 – The excited electrons are driven away and exit the scene via ‘easy flow’ electrical conduits (wires). The result is a loss of what was a balanced amount of positive and negative electrons.
- Step 3 – Careful engineering capitalizes on this imbalance by designing a pathway for the electrons to flow to the area in which they are lacking. This electron flow is known as electrical current.
- Step 4 – Once the electrons return, in their effort to balance the equation, they are once again struck by more photons (via sunlight) and the process is repeated.
Solar Panels: A Non-Consuming Energy Supply
One way to think of how solar panels actually work is to consider the example of our planet’s water cycle.
The sun shines and evaporates water, moving it into the atmosphere. This water is then cooled causing it to form droplets where the weight of it carries it back to the ground. Then, still being driven by gravity, it follows easy flow pathways, such as rivers and makes its way back to where it came from.
This is very similar to the power producing electron flow of solar panels. The sun shines, which causes electron movement, which changes the electron balance, which then causes electrons to follow easy flow pathways in order to return them back to their point of origin.
One can see that this process is contained, cyclical and thusly, non-consuming.
To reiterate, nothing is ever consumed. Electrons are simply moved – the result of bombarding sunlight photons and the careful engineering of electrical driving fields and easy flow electron pathways.
And because nothing is ever consumed, then it is by nature, easily sustainable.