Do Solar Panels Lose Power in Partial Shade? The Impact Explained
Solar panel is built to collect sunlight and transform it into electricity. That said, it does lose power when it is partially shaded. It is important to know how partial shading impacts the efficiency of your solar energy system and what you can do to maximize energy output to get the most out of your panels.
How Solar Panels Work
Solar panels function by leveraging photovoltaic cells to convert sunlight into electricity. They consist of critical components like solar cells, inverters, and wiring systems. The process starts when sunlight hits the solar cells, generating direct current (DC). The direct current is then converted into alternating current (AC) by an inverter, making it compatible with home appliances and electrical systems.
Knowing this fundamental energy creation process is important to understanding how shading can impede the overall functionality of the system.
What Is the Cause of Solar Shading?
Solar panel shading is typically caused by the following factors:
● Trees or Plant Shadows: Nearby trees or plants can cast shadows on the panels at certain times of the day, reducing sunlight exposure.
● Buildings or Other Structures: Buildings, chimneys, and other structures may block sunlight during sunrise or sunset.
● Seasonal Changes: The sun's angle changes throughout the year, with lower angles in winter causing more shading.
● Weather Conditions: Cloud cover, haze, or snow can reduce sunlight intensity, impacting energy output.
● Birds or Other Animals: Droppings or debris from birds or animals can accumulate on the panels, blocking sunlight and reducing efficiency.
● Dirt and Debris: Dust or pollution accumulating on the panels can obstruct sunlight and reduce efficiency.
The Impact of Partial Shade on Solar Panel Performance
Partial shade can lead to a decrease in the performance of solar panels.
Power Loss
Different types of shading, either from tree branches or the shadows of surrounding buildings, contribute to power loss. Shading can be categorized into two types: partial shading and full shading. When a solar panel is partially shaded, it still generates power, albeit with reduced efficiency. On the other hand, full shading completely prevents any power output from the shaded panel. Simply put, partial shading results in a progressive decline in performance, and full shading causes a sudden stoppage of power output.
Furthermore, research shows that even partial shading on solar panels can significantly affect their output. When 10% of the panel's surface is shaded, the power loss can be approximately 2.3% in efficiency, which translates to a reduction of about 12.41 watts per panel. This demonstrates that even slight shading can noticeably impact the overall performance of a solar system. When 44% of a solar panel is shaded, the power output loss can reach as high as 80%. This extreme shading results in the solar panel's efficiency being nearly completely lost, underscoring the importance of avoiding shading when installing solar systems. It also highlights the need to ensure that the panels remain clean and unobstructed for optimal performance.
The precise effect will differ subject to the location and time of the shading, but any shading is to be avoided for maximum performance.
Effect of Series Connection of Solar Cells
The majority of solar panel systems are made up of series-connected cells. In this arrangement, the entire series is affected when one cell is in shade. Shading, even on a small area of the panel, decreases the current output. To counteract this, bypass diodes are implemented to minimize the effect of shading. Nevertheless, shading on large areas of the panel has a considerable effect even with the use of bypass diodes.
Variations of Shading Effects
The effect of shading on electricity generation can vary throughout the day. For example, during early morning or late afternoon, the sun is lower in the sky, and the shadows cast by surrounding buildings or trees become larger, causing a higher loss of power. But at noon, when the sun reaches higher, the effect of shading is less. As sunlight's angle changes throughout the day, solar panels are affected by shading differently with varying levels of effect.
Uneven Lighting Effects
Partial shading can cause uneven lighting across the panel, leading to instability in energy output. This issue is particularly prominent in traditional series inverter systems, where even a small area of shading can lead to a noticeable drop in performance.
How to Minimize Power Loss from Partial Shade
Here are some effective optimization methods:
Panel Placement and Design
The first step in preventing shading is choosing the right location for your panels. Avoid placing panels under overhanging tree branches, nearby buildings, or anything else that could cast a shadow. Panel design is also important—installing the panels at the right angle and adjusting them based on seasonal changes can help minimize shading impacts.
Using Microinverters or Power Optimizers
Microinverters or optimizers are the ultimate for reducing the effect of shading. Microinverters enable every single panel to work separately so that the shaded panel never pulls down the system output as a whole. Power optimizers do the same with the system's output for every single panel so that the system is optimum no matter how some panels are shaded.
4 Benefits of Microinverters
Microinverters allow each panel to work independently, preventing shading or faults from affecting the entire system:
● Increased Efficiency: Reduces performance drops even with shading.
● Extended Lifespan: Lightens the load, extending the system's lifespan.
● Lower Maintenance Costs: Independent monitoring helps identify and solve issues quickly.
Application of Power Optimizers
Power optimizers optimize the output of each panel, especially effective in shaded areas:
● Reduced Power Loss: Minimizes efficiency losses due to shading or panel damage.
● Improved ROI: Reduces long-term energy losses, boosting overall system capacity.
● Increased Stability: Independently adjusts panel outputs, ensuring system stability.
Long-Term Energy Savings
Although the initial cost is higher, optimized systems can significantly lower energy bills:
● Lower Electricity Bills: Increases energy generation, reducing reliance on external power.
● Enhanced Energy Independence: Decreases dependence on the grid, boosting self-generation capacity.
Regular Maintenance and Trimming
Routine maintenance is crucial in maintaining your solar panels' optimal performance. This involves pruning trees and cutting any obstacles that can create shading. Regular washing of the panels also prevents dirt and debris from blocking sunlight, maximizing their power-generating capabilities.
Considerations for Mounting Solar Systems in Shady Places
Prior to the installation of a solar system in a shaded area, a shading analysis should be done. Professional consultation and advanced tools can determine how the performance of the system could be impacted by shading. By taking this step beforehand, the system can be designed to be as efficient as possible, even for locations with possible shading problems.
A Portable Solar Panel
If you're looking for an easier and flexible way to tackle shading issues, the EcoFlow NextGen 220W Bifacial Portable Solar Panel is the perfect choice. Its bifacial design maximizes energy collection efficiency, especially in partially shaded environments, effectively reducing the impact of shading. Even when faced with obstructions, it maintains high power output, ensuring that partial shading won't significantly affect your energy generation.
Maximizing Solar Panel Efficiency in Shaded Areas
If you are seeking an easier and more universal fix for removing problems with shading, the EcoFlow NextGen 220W Bifacial Portable Solar Panel is ideal for you. Its bifacial panel layout increases the effectiveness for energy output, most particularly for partial shading regions, practically reducing the impact of shading. You still receive maximum output for the panel regardless of obstructions, so partial shading will not impact your energy output greatly.
FAQs about Solar Panel
Q1: What are the advantages of microinverters over traditional inverters?
Microinverters are so powerful that they can operate each panel individually, so that the output of one will not affect the rest. Even if a few of the panels are cast in shade, the rest are still working optimally, effectively generating electricity. In comparison, regular inverters operate the system collectively, so that if the output of one panel declines, the performance of the overall setup will be affected.
Q2: How to determine if solar panels need cleaning under partial shading?
There is a definite energy output breakdown, combined with the piling up of leaves, debris, or soil on the solar panel surfaces, which means that cleaning is due. It is necessary to check these surfaces frequently, especially after a storm or a sudden breeze, so that any blockage that could otherwise inhibit sunlight from getting to them is averted.
Q3: Does partial shade influence the lifetime of solar panels?
Partial shade will not significantly reduce the life of the panels themselves, but can inhibit performance. If the panels are subject to regular shading without the benefit of optimization technology, such as microinverters or optimizers of power, the output of the system, and thus the overall return on investment, can be severely compromised.