Home TECH TOOLS Renewable Energy Resource Analysis

Solar Resource Analysis:

Solar resource analysis is simply a measurement of your solar assets at your location. This measurement can be quantified by:

1. Identifying your site photovoltaic potential: through solar insolation maps such as the solar resource maps of Canada, and
2. Accurately mapping the shade issues at your specific location.

Identify your site photovoltaic potential - Canada:

Data can be obtained directly for individual municipalities (over 3500 municipalities are included) by selecting a municipality in the Natural Resources Canada searchable solar database here. A search can be performed by entering all or part of the municipality name (a minimum of 3 characters is required in the search string), or by browsing municipalities listed by province, alphabetically.

Illustration of different PV array orientations provided by NRCan

The database provides 5 different values as represented in the above picture. These values help determine the potential difference in solar output for a solar array at different fixed angles, or the difference in output between fixed and tracking arrays.

Example (taken from Natural Resources Canada database)

Photovoltaic (PV) potential (kWh/kW) and mean daily global insolation (MJ/m2 and kWh/m2) data are presented below for the selected municipality. Data is presented for each month and on a yearly basis for 6 different PV array orientations.

London, Ontario
Geographic location -> -81.24E,42.99N
PV potential (kWh/kW)

The values above represent the average number of bright sunlight hours per day that fall on the given array orientations. These numbers (together with any deductions for shade issues as discussed below) can be inserted into any PV calculator tool to discover the amount of kWh per day produced for your specific application.

Accurately Mapping Shade Issues:

By combining the site-specific shading data of the Solar Pathfinder™ with the published solar radiation figures, an accurate solar site analysis can be made. This insolation data, on an hourly and monthly basis can then be applied to architectural, engineering, solar, and ecological applications.

The diagram is also specific to the application: “South-facing” (for Northern hemisphere) or “vertical” is for applications of 20-90 degrees tilt – usually solar; “Horizontal” is for applications of 0-20 degrees tilt – usually ecological (For the flexibility of calculating radiation of any azimuth and any tilt angle, use our Solar Pathfinder Assistant software in addition to the Solar Pathfinder).

Because the Solar Pathfinder™ works on a reflective principle rather than actually showing shadows, it can be used anytime of the day, anytime of the year, in either cloudy or clear weather. The actual position of the sun at the time of the solar site analysis is irrelevant. In fact, the unit is easier to use in the absence of direct sunlight. It could even be used on a moonlit night.

The Pathfinder has an integral bubble level and magnetic compass to facilitate quick instrument set-up. The unit and diagrams are engineered to adjust for magnetic declination to face “true south” (for Northern hemisphere), not “magnetic south”. A locking mechanism secures the adjustment.

Once the Solar Pathfinder™ has been properly set up, the user traces the outline of the horizon’s reflection seen on the dome onto the underlying diagram by inserting a white marking pen (included) through the slots on the side of the unit. The traced line shows exactly at what hours of the day and months of the year an obstacle will shade that particular location. The picture below shows a Solar Pathfinder™ being used at a typical solar site. Notice how the reflected image of the tree-line is sighted coincidentally with the diagram below it. The diagram, also pictured, is a site tracing of the same site. The tracing becomes a permanent record of the solar data.

The small numbers across the arcs represent the percentage of solar insolation in half-hour segments throughout the day – each month’s arc totaling 100%. The sum of the unshaded numbers along a particular monthly sunpath represent the percent of the total available solar energy for an average day during that month, as compared to a completely unobstructed site.

In the example tracing to the right, this particular site has only 78% solar availability for December [obtained by adding the unshaded numbers along the December sunpath (7+8+8+8+8+7+7+6+5+4). August had 97% solar availability (1+2+2+3+4+5+6+6+7+7+7+7+7+7+6+6+5+4+3+2).

To translate the Site Percent value obtained as above to kWh/m2/day, take the solar radiation data based on unobstructed site for your installation orientation (i.e. fixed, 1-axis, 2-axis, etc.) and multiply it by the daily Site Percent.