If you would like to save a whole lot of money on energy costs, and maybe even make some additional money on the side, not to mention if you would like to be as environmentally friendly as possible, then something to consider is getting a solar panel array for your home.
With the right kinds of solar panels, if you live in a fairly sunny area, you can produce more than enough power to meet the electricity requirements of your whole home, and then some.
All of that excess power can be sent straight into the power grid and distributed to other areas in need of power, and yes, this is at a cost, or in other words, you can make a neat profit selling that surplus energy to the utility company in your area.
Now, with all of that being said, if you want to meet the electricity requirements of your home, and then maybe make a profit on the side, your solar panels need to be performing at peak capacity, and a lot of this has to do with how they are installed, particularly when it comes to being exposed to as much direct sunlight as possible.
This, therefore, raises the issue of how well solar panels work in the shade, if at all. Right now, we want to figure out whether or not solar panels work in the shade, and if so, how well.
Do Solar Panels Still Work in the Shade?
Solar panels do of course need sunlight in order to function. That’s just the way it is. Without getting too deep into the science of it, the individual cells of solar panels work to absorb photons that the sun’s rays release, or in other words, they collect light energy. Then, through a special process, they convert that light into usable electricity.
Therefore, it serves to reason that more sunlight is better, and this is of course true. Solar panels always work best in strong and direct sunlight. The brighter the light the more photons there are to absorb. Pretty simple right?
So, what about the shade? Will your solar panels still work if they are sitting in the shade of a tree, another house, or anything else of the sort?
The answer here is that yes, solar panels will still work when in the shade, just like they also still work on cloudy or rainy days. Now, the reality here is that of course, solar panels won’t be able to absorb nearly as much light when sitting in the shade, and therefore won’t produce nearly as much energy as they would when sitting in direct sunlight.
For those of you who don’t know, this issue is technically referred to as PV shade loss, or in other words, how much energy output is lost due to the shade, and this is quite a serious issue, because it’s not just the cells that sit in the shade that are affected, but all of the cells. Let’s move on and explain this issue below.
Solar Panel Efficiency When Shaded
Alright, so the fact of the matter is that shade is a much bigger problem than one might think. So, you have a solar panel array with 36 cells, and a full 35 of those cells are in the sun, but just one is shaded.
Can you guess how much the power output is reduced here? If you said anything under 75%, you would have been wrong. Yes, that’s right, shading just one of those 36 cells can lead to an overall reduction in power output by a whopping 75%.
It would serve to reason that shading just one cell of 36 would reduce output by just 1/36, or somewhere around 3%, but that’s not how it works. When the flow of current through a single cell is reduced, the flow is reduced in all of the cells. It’s like a clogged pipe with water running through it. One small clog in one small section of the pipe leads to a standstill from front to back.
All of the solar cells in a string must operate according to the maximum current flowing through the cell sitting in the shade, and as you could imagine, this has big-time consequences for overall power output. As they say, a chain is only as strong as its weakest link, a rather perfect analogy for this topic indeed.
How to Prevent Power Loss Due to Shade
Before we call it a day, we want to provide you with some important tips on how to prevent this issue from occurring in the first place. Yes, we will talk about positioning, but there are also some other much higher-tech methods of dealing with the issue of solar panel shading, so let’s take a look.
Positioning is Everything
Of course, it all starts with the position in which the solar panels are arranged and the surrounding terrain. All sorts of things like other houses, trees, hills and mountains, and even adjacent solar panels can cause this issue. Therefore, you definitely want to put some good thought into exactly how you will position and arrange those solar panels.
The Arrangement of Strings
What you also need to think about here is how many strings of cells you have and how they are arranged. Generally speaking, the best approach here is to keep all shaded cells in a single string (or as many as is required).
This way, you will have one or two strings that are shaded, and the rest that are all sitting in the sun. The fewer strings of cells you have that receive shade, the higher the power output will be. On the other hand, if every string has a single cell that is shaded, then all of your strings will suffer from this problem.
Using Bypass Diodes
If you have no choice but to put up your solar panels in a way that a lot of them get shade, a good thing to look into is getting panels that have more than the usual amount of bypass diodes. Bypass diodes allow the current of electricity to bypass those cells that have a lower current (in this case due to shade) and keep flowing without being greatly reduced.
Now, most panels have one of these diodes for every 20 cells, which is ok, but not great. The more of these bypass diodes are present, the less of an effect some shade will have on the whole array.
Using Module Level Power Electronics
The other thing that you can do in order to increase the efficiency and output of shaded solar cells is to use module level power electronics, which include both microinverters and DC optimizers. A microinverter system, to keep things simple, allows each of the cells to operate at the maximum possible capacity without affecting adjacent cells.
A DC optimizer also works to this same effect, more or less, but functions a little differently. With microinverters, each panel has an inverter that converts DC to AC, but with DC optimizers, although panels are also serviced individually, a DC to AC inverter is still required.
There are small nuances between the two, but the bottom line is that they can both help mitigate the issue of shaded solar panels.
The Bottom Line
Now that you know just how much power loss even a little bit of shade leads to, and now that you know how to prevent and mitigate this problem from occurring, you can use your solar panels to produce as much power as humanly possible.