Insolation and Solar Radiation
How solar panels relate to insolation and solar radiation
Insolation
We recieve energy from the sun in the form of solar radiation. Solar panels make use of this radiation to generate
electricity. The amount of solar radiation that strikes a single location over a given period of time (usually one day)
is called insolation.
Horizontal Insolation
Horizontal insolation is another, more precise way to measure the amount of solar radiation recieved by a flat,
horizontal surface such as a pool, a skyscraper rooftop, or a soccer field. Measuring the amount of solar insolation
an area recieves in a given period of time is useful to:
- Determine the amount of sunlight a solar panel can absorb if it were placed in the area of horizontal insolation
- Find regional patterns of horizontal insolation
- Make informed decsions about the use of solar power in these areas
The amount of horizontal insolation recieved in any given area in temperate North American can vary by as much as a
factor of 6. Depending on where you live, the amount of regional solar insolation you experience will determine how
effective your solar panel system will be.
Regional Insolation Figures
In the United States, the average insolation index of the southwest is much higher than in central and southeastern
America with as much as about 6 to 8 3.5 kWh/m2 a day, where the amount of regional solar insolation is
markedly lower. In the northeast and extreme northwest, solar panels are the least effective, pulling in under 3.5
kWh/m2 per day These figures are based on year-long averages.
As you can see, if you live in Southwestern United states, especially in Arizona or Southern California, your solar
panels will be working at a very high efficiency rating, and you will experience outstanding power output year round.