This article introduces the common reasons why solar power generation decreases and the corresponding solutions.

1. Dust or Dirt on the Surface of Solar Panels

This is one of the most common causes. Dust, bird droppings, leaves, or air pollutants can accumulate on the surface of solar panels, blocking sunlight from reaching the photovoltaic cells and reducing power generation efficiency. Studies show that light dust may cause 5%–15% power loss, while heavy contamination may lead to up to 40% reduction in output.

Solutions

• Clean the solar panels regularly (recommended every 3–6 months)

• Use a soft cloth or clean water for washing, and avoid hard brushes or corrosive chemicals

• Increase cleaning frequency in areas with heavy dust or pollution

2. Shading

Shadows from growing trees, nearby buildings, antennas, or other obstacles can affect the efficiency of solar panels. Even partial shading on a small area can impact the output of the entire panel string.

Solutions

• Trim tree branches that block sunlight from reaching the panels

• Adjust the installation position of the solar panels

• Use systems with power optimizers or micro inverters to reduce shading impact

3. Weather and Seasonal Changes

Solar power generation is closely related to weather conditions. Continuous cloudy days, rain, snow, or air pollution can reduce the intensity of sunlight reaching the panels, which leads to lower electricity production. For example, thick cloud cover may reduce power output by more than 80%.

In addition, during winter, the solar altitude angle is lower and daylight hours are shorter, so system power generation is usually lower than in summer.

Solutions

• Compare historical power generation data to determine whether the change is seasonal

• Regularly check the system monitoring platform to analyze generation trends

4. Inverter or System Equipment Failure

The inverter is one of the core components of a solar system. It converts the direct current (DC) generated by solar panels into usable alternating current (AC). Inverter faults, incorrect settings, or reduced efficiency can all lead to decreased power generation.

Solutions

• Check whether the inverter shows any alarm or error codes

• Review the system monitoring app or platform

• Contact professional technicians for inspection or maintenance

5. Installation or Wiring Issues

If the installation angle, orientation, or wiring of the solar system is not optimal, it can also affect overall power generation efficiency. For example, improper panel tilt angles, loose wiring, or cable losses can all result in energy loss.

Solutions

• Check whether system wiring connections are loose

• Ensure the panel orientation and tilt angle are appropriate

• Perform regular system inspections and maintenance

6. Natural Degradation of Solar Panels

Solar panels gradually experience performance degradation as they age, which is a normal phenomenon. Typically, photovoltaic modules degrade at a rate of about 0.5%–1% per year.

Solutions

• Regularly compare current power generation with initial system performance data

• Consider replacing or upgrading the system if panel degradation becomes significant