The power generated by a solar panel is measured in kilowatt-hours (kWh) rather than watts, as watts represent the instantaneous power output. To estimate the annual energy production of a solar panel, you can use the following formula:

Annual Energy (kWh)=Power Rating (kW)×Solar Hours×Performance FactorAnnual Energy (kWh)=Power Rating (kW)×Solar Hours Performance Factor.

In this formula:

• Power Rating is the maximum power output of the solar panel in kilowatts (kW).

• Solar Hours represent the average number of peak sunlight hours per day for your location.

• Performance Factor is a factor that accounts for losses due to factors like temperature, dirt on the panels, and inefficiencies in the system.

Assuming a 400-watt solar panel, the power rating would be 0.4 kW0.4 kW. The solar hours and performance factor will depend on your location and the specific characteristics of your solar panel system.

As an example, let's assume an average of 4 solar hours per day and a performance factor of 0.75 (or 75%). Using the formula:

Annual Energy=0.4 kW×4 hours/day×0.75

Annual Energy=1.2 kWh/day

To find the yearly energy production, you would multiply this value by the number of days in a year. If we assume 365 days:

Annual Energy≈1.2 kWh/day×365 days

Annual Energy≈438 kWh

So, in this example, a 400-watt solar panel could potentially generate around 438 kilowatt-hours of energy per year under those conditions. Keep in mind that these are rough estimates, and actual performance may vary based on environmental factors and the specific characteristics of the solar panel system.