2025.07.25
Solving the problem of solar panel shading is the key to improving the power generation efficiency of photovoltaic systems, because even a small area of shading (such as a leaf, bird droppings, and wire shadows) may cause a significant drop in the power generation of the entire string of components (up to 30% or more). This is because the cells in the component are connected in series, and shading will cause the affected cells to heat up and become resistors, dragging down the current of the entire string.
The following are some effective solutions, covering multiple levels of prevention, design, technology and maintenance:
I. Prevention and design stage
1. Detailed site selection and shadow analysis:
l Year-round dynamic simulation: Before installation, use professional shadow analysis software (such as PVsyst, Helioscope, etc.), input accurate longitude and latitude, terrain, surrounding buildings, trees and other data, and simulate the shadow conditions in different seasons and time periods throughout the year (especially when the solar altitude angle is the lowest on the winter solstice).
l Field survey: Conduct multiple field inspections during the planned installation period (such as 9 am to 3 pm) to observe the actual shadow changes.
l Avoid shadow areas: Based on the analysis results, strictly avoid installing components in locations that will be long-term or severely shaded. It is better to reduce the number of installations to ensure the quality of the unobstructed area.
2. Optimize system design:
l Module layout: If it is impossible to completely avoid shadows (such as chimneys and ventilation pipes), connect the modules that may be affected by the shadows in series (using smaller MPPT channels) to avoid affecting other unobstructed strings.
l Inverter selection:
Multi-channel MPPT inverter: Select an inverter with multiple independent maximum power point tracking circuits. In this way, the obstructed strings can work independently in the best state without affecting other strings.
DC optimizer: Install optimizers at the module level (such as SolarEdge's Power Optimizer, Tigo's TS4 series). This is the most common and effective solution to solve the problem of shading or complex roof shadows in installed systems.
Microinverter: Equip each (or 1-4) modules with an independent microinverter (such as Enphase). The modules work completely independently, and the shading only affects the blocked module (or modules) and has no effect on other modules. This is the ultimate solution to the shading problem, especially for new roofs with very complex shadows.
l Module orientation and tilt: Adjusting the orientation and tilt within the allowable range may help avoid shadows during certain periods of time.
II. Solutions for installed systems
1. Adding module-level power electronics:
l DC optimizer: This is the first choice for upgrading existing string inverter systems. Installed on the back of each module or in the junction box.
Working principle: The optimizer allows each module to work independently at the maximum power point and output the adjusted optimal voltage/current to the inverter. Even if a module in a string is shaded, other modules can still output at full power.
Advantages: Significantly improve power generation under shading (up to 25% or more), provide module-level monitoring, enhance system safety (fast shutdown), and usually cost less than replacing with micro-inverters.
l Micro-inverter: If the original system inverter is old or faulty, consider replacing it with a micro-inverter system.
Working principle: Each module directly outputs AC power and connects it to the grid, completely eliminating the mutual influence between strings.
Advantages: Minimized shading effects (only the shading module is affected), maximum system design flexibility, high safety (no high voltage DC), module-level monitoring. Initial cost may be high, but long-term benefits and reliability are good.
2. Physically remove shading sources:
l Prune trees and vegetation: Regularly prune branches close to the array, especially fast-growing trees. Pay attention to safety and hire professional gardeners when necessary.
l Clean panels: Establish a regular cleaning schedule (such as every season, after rain, after dust/pollen season, after bird season) to remove dust, dirt, bird droppings, fallen leaves, and snow. Bird droppings are a common and serious point-shaped shading source.
Cleaning method: Use a soft brush, wiper, special cleaning agent and low-pressure water flow (or professional cleaning service). Always do it in the early morning, evening or cloudy day to avoid cold water cracking hot glass, and strictly follow the safety regulations for high-altitude work.
l Remove debris: Clean up debris that has fallen on the module.
3. Adjust or remove objects that cause shadows:
l Evaluate whether small obstacles that cause shadows (such as abandoned antennas and small decorations) can be removed or lowered.
l If new buildings or facilities may cause shadows, negotiate and plan in advance.
III. Continuous monitoring and maintenance
1. Install a monitoring system:
l Inverter-level monitoring: At the most basic level, you can see the power generation of the entire system or each MPPT.
l Component-level monitoring: If an optimizer or micro-inverter is used, be sure to enable its monitoring platform. This is the most direct and effective way to find shading problems. The monitoring platform can display the real-time and historical power generation performance of each component, quickly locate components with abnormally low power generation, and determine whether they are blocked (or other faults).
2. Regular inspections:
l Regularly (such as monthly or quarterly) visually check whether there are obvious obstructions (fallen leaves, bird droppings, snow, debris) on the surface of the components.
l Combined with monitoring data, conduct targeted inspections when abnormalities are found.
l Increase the frequency of inspections in autumn and winter (low solar altitude angle, longer shadows) and spring (trees begin to grow lush).
3. Analyze power generation data:
l Pay attention to the daily power generation curve. Under normal circumstances, it should be a relatively smooth peak. If the curve shows abnormal "concave", "double peak" or "flat top", it often indicates the presence of shading (or other faults such as hot spots).
IV: Summary and suggestions
l Prevention is better than cure: Investing in detailed shadow analysis and optimization design during the design and installation phase is the lowest cost and most effective solution. Selecting a multi-channel MPPT inverter is the most basic requirement.
l The preferred upgrade solution for installed systems: Add a DC optimizer. It can significantly improve power generation performance under shading, provide monitoring and safety functions, and is relatively economical.
l The ultimate solution for complex shading or new systems: Microinverters. Provide the highest shading immunity and design flexibility.
l Daily maintenance is essential: Regular cleaning and monitoring-based inspections are necessary to keep the system clear of shading and running efficiently. Bird droppings and fallen leaves are the most common and easily overlooked sources of shading.
l Safety first: For any work involving climbing on the roof, be sure to hire professional and qualified photovoltaic installation or cleaning service personnel.
sJoin the Sun-Earth Family Today
If you are looking for high-quality solar panels that deliver exceptional performance, durability, and value for money, Sun Earth Solar is the right choice. With our extensive product line, commitment to sustainability, and exceptional customer service, Ningbo Sun Earth are the ideal partner for all your solar needs.
Contact us today to learn more about our solar panel solutions and how we can help you get the most out of the sun. Together, Sun earth can achieve extraordinary things and create a brighter, more sustainable future for ourselves and our children.
Keywords：
Sun Earth Solar, Ningbo Sun Earth, Sun-Earth, Sun Earth, solar panel
