Solar Azimuth and Its Importance
Azimuth refers to the horizontal orientation angle of a solar panel relative to geographic north. For an installation in the Northern Hemisphere, an azimuth of 180° corresponds to true south — the reference position for maximizing annual energy capture.
Regardless of season, the sun describes an arc in the sky oriented toward the south of an observer in Canada. A surface oriented directly toward this average solar path thus receives the maximum integrated irradiation over the day and over the year.
Impact of Orientation on Annual Production
Simulations and field measurements available in technical literature allow orders of magnitude to be established for losses associated with different orientations, assuming a tilt angle fixed at the optimal value for each configuration:
| Orientation | Azimuth (°) | Estimated Production Loss (vs. true south) |
|---|---|---|
| True south | 180° | Reference (0%) |
| Southeast or southwest | 150° or 210° | ~2–5% |
| East or west | 90° or 270° | ~15–20% |
| Northeast or northwest | 45° or 315° | ~30–40% |
| True north | 0° | >40% |
These values are general estimates. Precise results depend on latitude, local sunshine profile and the tilt angle chosen.
Solutions When True South Is Not Available
Many Canadian residential buildings do not have a true south-facing roof surface. Several approaches can work around this constraint:
1. East-West Split
An installation splitting panels across east and west roof sections produces less than a true south installation overall, but offers a production profile spread more evenly through the day. This configuration may match a consumption profile with morning and evening demand rather than midday demand.
Canadian Context
In several provinces, notably Ontario and British Columbia, net metering programs allow excess production to be fed into the grid and recovered later. In this context, the daily production curve matters less than total annual production.
2. Oriented Mounting Structures
On flat or low-slope roofs, tilted mounting structures with free orientation allow panels to be positioned at the optimal azimuth regardless of building orientation. This solution is common for commercial buildings and multi-unit residential buildings in urban areas.
3. Ground-Mounted Installation
For properties with ground space, pole or ground-mounted structures offer complete freedom of orientation and tilt. Ground-mounted installations are also more accessible for snow removal and maintenance.
Shading: An Often Underestimated Factor
Orientation is only one efficiency parameter. A perfectly true south-oriented installation partially shaded by a tree or neighbouring building may produce less than a suboptimal azimuth installation without shade.
Deciduous trees present in many Canadian residential neighbourhoods create seasonal shading: absent in winter (a period of strong radiation in the Prairies) but present in summer. This dynamic should be evaluated specifically at each site before finalizing panel location and orientation.
Orientation Simulation Tools
Several publicly accessible tools allow production to be simulated according to orientation, tilt and location:
- RETScreen (Natural Resources Canada): clean energy project simulation tool developed by the federal government, available free of charge.
- PVWatts (NREL): online calculator developed by the National Renewable Energy Laboratory to estimate annual production based on customizable parameters.
- NASA solar data portal: global solar irradiation data accessible by geographic coordinates.
Magnetic Declination and Compass Use
In Canada, magnetic declination — the difference between magnetic north indicated by a compass and geographic north — can exceed 20° in some regions. When planning an installation, it is important to use geographic north (true north) as the orientation reference, not the magnetic north provided by a standard compass.
Tools such as Natural Resources Canada's application or the Canadian Space Agency website allow you to find local magnetic declination at the time of installation.