Sizing Your Solar System

Sizing your solar power system is a multi-layered issue. Typically, it is considered in terms of how many solar panels are necessary to meet specific energy goals (i.e., replace 50, 60, or 70 percent of electricity needs). Certainly the solar panels are the most visible part of the solar system proper and dictate the three-dimensional size of the system, but even the number of solar panels relies on several factors.

The two most important variables are power consumption and available sunlight.

Determining monthly and daily power consumption should be fairly easy with a stack of utility bills and some basic math. If you need help there are online resources to make the job easier.

Figuring out how much sunlight you can expect on a daily basis is a bit more complicated. Solar maps and other tools to calculate average daily sunlight for your region are available online as well. But there are other factors, such as the exact location of your home in relation to the sun, available roof or ground space, and shading.

To get a general idea for your ideal system size you need only the available sunlight and your daily power consumption. First you calculate the number of panels you need, which depends on the amount of energy you need to produce each hour. Then you can figure out how many batteries you’ll need as well (for off-the-grid or back-up systems).

Again, this will probably give you a rough estimate. A more detailed answer to the size question is best approached with a solar professional after a thorough site analysis has been done.

Photo features: SolarCraft

Posted on March 2nd in Going Solar by Dan.