Going Solar Chapter 2: Know your Earth

The Earth’s atmosphere plays a crucial role in filtering solar radiation before it reaches the surface, impacting the efficiency of solar photovoltaic (PV) systems. At the top of the atmosphere, the average annual solar radiation is about 1361 W/m², spanning from ultraviolet to visible and infrared light, with approximately half being infrared.

Our atmosphere, composed primarily of 78% nitrogen and 21% oxygen, along with trace amounts of water vapor and carbon dioxide, acts as a shield. The stratospheric ozone layer absorbs most of the Sun’s harmful ultraviolet (UV) radiation, while other molecules like water and carbon dioxide absorb specific wavelengths, creating distinct absorption bands.

The Solar Radiation Spectrum illustrates how atmospheric components filter out various wavelengths, reducing the spectrum seen at sea level due to ozone, oxygen, and water absorption. As sunlight passes through the atmosphere, its intensity diminishes, with maximum normal surface irradiance averaging around 1000 W/m2 on clear days at sea level. Cloud cover further affects solar radiation, with Earth receiving an average daily insolation of about 6 kWh/m² under ideal conditions.

Solar insolation quantifies the amount of solar radiation energy received over a specific area and time, crucial for evaluating PV system performance. Locations with higher solar insolation, typically found in cloudless deserts, offer greater potential for solar energy generation due to fewer atmospheric impediments.

To optimize the efficiency of solar PV systems, it’s essential to position them in areas with ample solar insolation. At Future Green Technology, we integrate this understanding into our solar solutions, harnessing the Earth’s abundant solar potential to deliver sustainable energy solutions worldwide.