How does shading affect solar? What are the types of shading?
The photovoltaic effect, which occurs whenever sunlight releases electrons from the silicon components that make up solar PV cells, is how solar photovoltaic (PV) systems produce energy. Thus, the entire installation produces less total solar power anytime a solar cell or panel does not receive sunlight because of shading or surrounding obstacles. The shade loss of a PV system is the name of this phenomenon.
What are the different causes of solar shading?
Shade can take on many forms on your panels.
Trees:
Probably, trees near your solar panel can trigger shading issues. Most housing units are in greenery, and rapidly expanding trees and plants can disrupt solar panel performance.
Other Solar Panels:
The other surrounding panels, in combination with trees, can shade solar panels. Based on the panel arrangement, neighboring panels can also cast shadows on panels at lower positions in the same framework. Usually, this problem only occurs in-ground mount systems.
Shaded Roof:
If a shaded roof has solar panels on it, several sections of the roof like pipes, chimneys, or dormers will also lead to sunlight blockage depending on the angle and time.
Weather Conditions:
Weather plays an important role in calculating the amount of sunlight reaching solar panels. Clouds partially block the sunlight, which leads to a reduction in exposure.
Fog:
The great news for people residing in such climate areas is that solar panels can generate energy in foggy weather as well. The capacity is more than in fog in the case of direct sunlight. The fog usually burns off during the mornings; even if your system does not function at optimum speed in the early morning, the solar panels will be able to absorb the sun’s rays by mid-afternoon completely. (assuming this is a clear day)
Why minimal shading can cause severe power loss in a solar energy system?
A shaded solar cell is comparable to a water pipe that has a blockage. The block prevents water from flowing freely across the entire pipe. Similar to how a shaded solar cell affects the electrical current flowing through the entire string.
This is important because the current set by the shaded cell must be used by every PV cell in the cell string. The unshaded cells are unable to perform at their highest potential due to this restriction. Every solar cell is essentially a chain of links. The “weakest link” is the shaded cell, which lowers the power availability of all the other cells. This explains why even slight shadowing may have such a significant impact on a solar PV system’s overall power production.
Similarly, If even a single solar module is shaded, the current flowing through the entire string of modules can be reduced significantly. The entire PV system consequently underperforms, failing to provide the customer with the energy, savings, and reduced emissions they were hoping for
How to mitigate the shading losses in a solar panel system?
The solar installer can utilize a variety of different solar design techniques to reduce shading losses. Using various stringing designs, bypass diodes, and module-level power electronics are some examples (MLPEs).
1- Stringing Arrangements
Strings create by joining modules in series, and strings can be connected to an inverter by joining them in parallel. A string’s modules must all have the same electrical current flowing through them. In contrast, parallel strings must all have the same voltage.
A shaded solar module in a string can severely reduce the power output of the string. The power output of a parallel string is not, however, affected by a shaded module in one string. Therefore, it is possible to maximize the total overall power output of the solar array by combining shaded modules into different strings.
2-Bypass Diodes
Solar modules contain bypass diodes, which enable electrical current to “skip past” shadowed areas of the module. Bypass diodes allow the higher current of the solar cell strings without shading to pass around the shaded cell string. The PV cells that skipped through lose some of their solar power as a result of this, though.
Technically, each solar cell may have its bypass diode installed. However, a standard solar module will only include three bypass diodes due to cost considerations, essentially arranging the cells into three series cell strings. Typically, there will be one bypass diode for every 20 cells in a 60-cell module, for instance.
3-Module Level Power Electronics (MLPEs)
Individual solar PV modules can be linked with MLPEs to improve performance while it’s shadowed (though there are other benefits, such as mismatch mitigation and module-level monitoring). DC optimizers and microinverters are MLPEs and by adding them maximum power point tracking is carried out at the module level.
What happens if one solar panel is shaded?
The output power of an entire solar panel system decreases by 50% when even one cell in the module is shaded to 50%. No matter how many cells are in the string, if one cell is entirely shaded, the module’s output power will be 0.
Does shade damage solar panels?
When there is no shade on solar panels, they perform at their best. A shadow cast on even a small portion of one solar panel in your solar array can risk the system’s overall output.
According to the experts, there are chances that homeowners could be losing as much as 40% of the potential of solar power generation due to shade. Shades act as a shadow that is cast over a panel; this reduces the amount of sunlight reaching the surface. Shades affect the power output of the PV modules.
Concluding, Shading is an important concern as it directly impacts the performance of your residential solar panel system. You cannot achieve the saving and power production goals if your solar panels are facing shading.
However, choosing the right solar installation company can help you out with this issue. A good solar installer designs your system by keeping all factors in mind and making sure that your solar panels are the best-fit place for your home. Contact Solar SME for a premium solar install experience as we are NABCEP Certified and offer quality installation and great customer service.
