What are the factors that affect PV power generation?
Area and material properties of skylight panels
In photovoltaic power generation systems, skylight panels play a vital role. Let’s first talk about the area of skylight panels. We know that solar energy is a widely available but relatively dispersed energy source, and skylight panels are like a huge “energy collector”. The larger the area of the skylight panel, the wider the space it can cover, just like a big pocket can hold more things, and the more solar radiation it can receive.
Let’s look at the material properties of the skylight panel. Modern photovoltaic power generation technology is constantly developing, and the material properties of the skylight panel are one of the key factors determining the efficiency of power generation. High-performance skylight panels have special physical and chemical properties. For example, it may be optimized in micro structure to make the interaction between photons and electrons in the material more efficient. This efficient interaction can improve the efficiency of photoelectric conversion, just like a sophisticated energy conversion machine that can convert more solar photons into electrons in electrical energy.
Local light time
Light time is an important factor that cannot be ignored in affecting photovoltaic power generation. First, let’s talk about the significance of sunshine duration. Different regions of the earth have significantly different sunshine duration due to factors such as geographical location, climate and season. For photovoltaic power generation systems, sunshine duration is like an indicator of working hours. The longer the sunshine duration, the longer the photovoltaic system can continue to generate electricity, just like the longer a worker works, the more products he can produce. In areas with abundant solar energy resources, such as desert areas, the sunshine duration in a day may reach 10-12 hours or even more. Under such long sunshine duration, photovoltaic cells can continuously convert solar energy into electrical energy, thereby accumulating more electricity.
From the perspective of energy utilization, the length of sunshine duration is directly related to the total power generation of photovoltaic power generation systems. We can imagine that a region with only 2-3 hours of sunshine per day and a region with 10 hours of sunshine, under the same photovoltaic power generation equipment, the latter will definitely generate much more power than the former. This also explains why sunshine duration is an important consideration when selecting a site for large-scale photovoltaic power generation projects.
Elevation and orientation of the skylight
The elevation and orientation of the skylight have a profound impact on the efficiency of the photovoltaic power generation system. Let’s talk about the elevation angle first. The altitude angle of the sun is constantly changing in different geographical locations and seasons. A suitable elevation angle can make the skylight better capture sunlight, just like adjusting the angle of a mirror so that it can accurately reflect light. For example, in the winter in the northern hemisphere, the solar altitude angle is low, and the elevation angle of the skylight should be appropriately increased, so that the skylight is more perpendicular to the sunlight, thereby improving the efficiency of the skylight receiving solar radiation. On the contrary, in summer, the solar altitude angle is high, and the elevation angle needs to be reduced accordingly.
Let’s look at the direction of the skylight. The direction of the skylight needs to be adjusted according to the geographical location and season to maximize the reception of sunlight. The earth is a sphere, and different geographical locations receive different directions of sunlight. For example, near the equator, the sun is basically vertical, while in high latitudes, the sunlight is more inclined. Therefore, in photovoltaic power generation systems near the equator, the skylight can be placed horizontally or at a nearly horizontal angle; while in high latitudes, the skylight needs to face south (Northern Hemisphere) or north (Southern Hemisphere) to better receive sunlight. Moreover, the sun’s trajectory changes with the change of seasons. In summer, the sun’s trajectory in the sky is more towards the north (in the northern hemisphere), so the direction of the lighting panel needs to be adjusted slightly to the north; in winter, the opposite is true and needs to be adjusted to the south.
Climate conditions
Climate conditions are a complex factor that affects photovoltaic power generation, including temperature, humidity, and wind speed. Let’s first look at the impact of temperature. In high temperature environments, the efficiency of photovoltaic panels will decrease, thereby affecting the amount of power generated. This is because the working principle of photovoltaic cells is based on the photoelectric effect of semiconductors, and the increase in temperature will change the physical properties of semiconductors. For example, the increase in temperature will intensify the lattice vibration of semiconductor materials, resulting in a decrease in the mobility of electrons, just like the speed of vehicles slowing down on a crowded road. In this way, the conduction of electrons in the material is hindered, and the photoelectric conversion efficiency will decrease. In addition, high temperatures may also cause thermal stress inside the panels, and the service life of the panels will also be affected if they are in a high temperature environment for a long time.
Wind speed plays an important role in the heat dissipation of photovoltaic systems. Appropriate wind speed helps to improve system efficiency. When the wind blows over the photovoltaic panels, it can take away the heat on the surface of the panels, just like blowing a cool breeze to the panels, reducing the temperature of the panels. In some areas with rich wind resources, such as coastal areas or plateau areas, the rational use of wind speed to dissipate heat can effectively improve the efficiency of photovoltaic power generation systems. However, if the wind speed is too high, it may also cause damage to the photovoltaic system, such as blowing down the bracket or scratching the protective layer on the surface of the panel. Therefore, when designing a photovoltaic system, it is necessary to consider the local wind speed conditions and select a suitable bracket structure and installation method to ensure the stability and safety of the system under different wind speed conditions.
Humidity is also a factor that affects the efficiency of photovoltaic power generation. When humidity is high, the surface of PV modules tends to accumulate water or condensation. The presence of a thin film of water vapor on the glass surface results in a decrease in transmittance.Photovoltaic modules perform photoelectric conversion by receiving sunlight. The reduction in transmittance means that less sunlight can reach the inside of the panel, thereby affecting the power generation efficiency. In addition, water accumulation or condensation may also cause corrosion or short circuit on the surface of the module, further affecting the normal operation of the photovoltaic power generation system.
Surface obstructions
Surface obstructions have a significant impact on photovoltaic power generation, mainly including two types: dust and shadows. Let’s talk about the impact of dust first. Dust reduces the transmittance of sunlight, reducing electricity generation. In actual photovoltaic power generation applications, photovoltaic modules are usually exposed to outdoor environments, and dust in the air will gradually settle on the surface of the modules. These dust particles are like a thin barrier that blocks direct sunlight. From an optical principle, dust will scatter and absorb sunlight, reducing the effective light that can reach the inside of the solar panel. For example, in some areas with heavy sand and dust, after a period of time, the surface of the photovoltaic module may be covered with thick dust. At this time, if it is not cleaned in time, the power generation may drop significantly.
Shadow is also an important influencing factor. Obstructions such as trees and buildings will cause shadows and affect local power generation. When part of the photovoltaic module is blocked by shadows, the cells in the blocked part cannot normally receive sunlight for photoelectric conversion. When selecting and laying out the actual photovoltaic power station, it is necessary to fully consider the obstructions in the surrounding environment and try to avoid the impact of shadows on photovoltaic modules.
