How do I calculate my Solar Potential?
With this we mean how much electricity you will, realistically, produce through the year. There are multiple, excellent and free solar calculators out there. Here are our two favorites.
PVWatts, by the National Renewable Energy Lab in the USA. We like this one because of its simple, yet effective user experience.
Step 1: Enter your exact address, the calculator will take not only your location, but also weather data into consideration.
Step 2: After confirming your address, you are directed a simplified list of parameters, as shown here.
Our solar panels produce a max of 320W, so we enter 0.32, because this field is always in kW or kiloWatts, meaning in steps of 1000 Watts. If you buy 5 panels, for instance, you simply multiply that by 5 and insert 1.6kW. Tilt depends on your location, but a general, decent tilt for all-year-round is between 25° and 35°. Use the free Solar Angle Calculator to check the general angle for your home.
This is really all you need, so don’t worry about the advanced parameters. Even changing the tilt angle for our location in Houston by from 20° to 25° only estimates a difference of 3kWh per year. You can play around with this angle a bit and find the optimal angle for your location.
Step 3: After hitting “Go to” again, you will be taken to the results, which are presented visually, but can also be downloaded with a data resolution down to the hour. The annual value calculated depends on your electricity price, which you can set in Step 2, below the Advanced Parameters.
PVGis, which is also a free tool and created by the EU Science Hub.
While it seems a bit more complex, it’s really just the site design. You follow the exact same steps and insert the same variables as in PVWatts. As you can see, we’ve changed the tilt angle, which is called “slope” in this calculator, to 35°, because we used Vienna, Austria as an example.
This also shows nicely the difference your location makes. The same panel will produce less in Austria, as you can see from the Yearly PV energy production value. However, when we compare the June results for Houston and Vienna, we see barely a difference. Both around 42 kWh for that month. The difference in electricity production comes mostly from the sun-hours, of which Houston has more.
There are a multitude of other calculators available online, from governments, as well as private companies. A simple google search will show you those.