The amount of energy your system can generate depends on several factors.
Configuration
A solar PV system can either be affixed to your rooftop or to the ground (e.g., in your backyard). A professional installer can provide advice on the optimal location and configuration of the system on your property.
Orientation
The optimal orientation of rooftop solar panels in Canada is south-facing. Still, east- and west-facing orientations can provide around 70% of the output of a south-facing solar PV system.
Obstructions
Your installer will assess your roof and/or ground area and survey it for any current or future obstructions. A professional assessment, including the measurement of solar irradiance (how much sunlight falls on your roof or property), is required to estimate your potential system production. If you intend to have your solar panels installed on your rooftop, you will typically need at least 3.7 m (12’) x 3.0 m (10’) of unobstructed area (clear of chimneys, roof vents, skylights, gables, and other protrusions).
Roof condition
If you intend to install panels on your rooftop, the roof covering (e.g., shingles) should be less than 10 years old, so that the solar PV system can remain in place for the duration of its warrantied life (e.g., 25 years). Since 2012, the standard for “solar-ready” roof construction in Canada has been a load limit of 5 lbs per square foot for solar panels, racking, and other equipment. A qualified solar installer will determine compliance.
Calculating potential output
Because the weather is not always consistent from year to year, production from your solar system can vary. Your installer should be able to offer some averaging factors to address the fluctuations.
In addition, your solar system can produce power for well over 20 years, so you will need to account for any future obstructions: Is that sapling going to branch over your solar panels in a decade?
Your solar installer will assess your solar potential using tools and calculators that account for all these important variables. Some free tools are available to customers for a preliminary check of solar potential. Check back with us for links to tools here as more options become available.
Calculating your energy needs
Your electricity consumption may change over the years as well. Improving energy efficiency, purchasing electric vehicles, how you use your AC system or installing electric heating will change your usage. These decisions may affect the overall size of your system. Energy storage can maximize the use of solar PV to meet local needs by storing energy and making it available when sunlight is not.