HOW MUCH ENERGY DOES A SOLAR PANEL PRODUCE?

Power energy output or wattage is a principal factor when comparing solar panel options. You’ve probably heard many say, “this solar panel has a wattage of 200,” or “the one I recommend is the 300-watt solar panel.” When shopping online or obtaining quotes for solar installations, you may have even come across numbers such as 100W, 210W, or 240W in the description of the panels. These numbers specifically represent a solar panel’s wattage, capacity, and power output.

What factors determine solar panel output?

When calculating the amount of energy a solar panel can produce, it’s important to understand the two key factors that help determine its power output: cell efficiency and size.

Let’s assess each factor separately to understand them a bit better.

Solar panel cell efficiency

High efficiency equals more energy produced. However, most solar cells can convert about 20% of the sunlight that hits them, into using solar energy. Therefore, high-efficiency solar panels will have a larger energy output.

Number of solar cells and solar panel size

To help simplify things further, we can divide solar panels into two size groups: 60-cell solar panels and 72-cell solar panels.

Typically, 60-cell solar panels are about 5.4 feet tall by 3.25 feet wide and have an output of about 270 to 300 watts.

Whereas 72-cell solar panels are larger because they have an extra row of cells, and their average output tends to lie between 350 to 400 watts. These panels are commonly used on larger buildings and commercial solar projects rather than on residential homes.

How much energy does a solar panel produce?

All solar panels are rated by the amount of DC (direct current) power they produce under standard test conditions. A solar panel's output is expressed in watts (W) and represents the panels theoretical power production under ideal sunlight and temperature conditions.

Let’s say you get 5 hours of direct sunlight per day in a sunny state like California. You can then calculate your solar panel output accordingly:

5 hours x 240 watts (example wattage of a premium solar panel) = 1,200 watts-hours, or 1.2 kilowatt-hours (kw/h).

Thus, the output for each solar panel in your array would produce around 500-550 kWh of energy per year.

Most home solar panels on the market today have power output ratings ranging from 100 to 300 watts, with higher power ratings preferred over lower power ratings. A solar panel's price is typically measured in dollars per watt ($/W), and the total solar panel wattage plays a significant role in the overall cost of the entire system.

What can you power with a single solar panel?

In the example above, the solar panel produces 1.2 kWh per day, which totals approximately 36 kWh per month. This would be enough energy to power certain small appliances, however, if you want to power a refrigerator or larger cooking appliances, you’ll need more solar panels.

Check out our article on the number of solar panels needed for your home to get a better understanding of the total amount of energy required to meet your unique power needs.