Our recommendation is that, at this point, solar trackers are not a good value proposition for applications in Ontario. In theory, the additional output yield for southern Ontario is in the order of 25-30% but the upfront cost is approximately 25% and the additional maintenance and replacement costs can be significant.

What are they?

Solar trackers involve the additional installation of motors, gears and electronics that allow an otherwise fixed system of solar panels to track the movement of the sun across the sun (either from day to night and/or across the seasons).

How much more output can I expect?

The gain from having a solar tracker depends largely on the latitude and the climate. The maximum gain that you may expect is in summer and at the greatest latitude (100% gain at the North and South poles in mid-summer, and no gain at all at the North and South poles in winter). In southern Ontario, the overall potential gain is in the order of 25-30% (according to data from Natural Resources Canada). In terms of real data, an engineering company in Pennsylvania is monitoring the performance of a solar tracked system with a fixed system (in 2009, for example, the gain was in the order of 15%). [link]

The realized gain also depends on:

1. Extent of cloud cover – with (heavily) cloudy days reducing the effectiveness of the panels (which then operate mostly from diffused instead of direct sunlight) and producing little advantage from the use of a tracker.
2. Reliability of tracking system – the system must be able to reliably “track” the sun and, for example, not be falsely triggered by the reflection of the sun off a cloud.
3. Placement of system – solar trackers can be used most effectively in areas with low horizons and locations that are shade free from dawn to dusk each day.

What are the disadvantages of a solar tracked system?

By adding moving equipment and electronics to an otherwise simple and long-lasting system, a solar tracked system increases the upfront cost substantially – by approximately 25%. In addition, a solar tracked system involves:

1. Repairs and maintenance – apart from the occasional spray-down to remove dust, a fixed system is virtually maintenance free for 20-30 years; a solar-tracked system requires regular maintenance. If the solar-tracked system breaks down when the solar panels are at an extreme angle, the loss of production until the system is again functional can be substantial.
2. Lifetime – a fixed system will last 30+ years and comes with a 25-year power performance guarantee; a solar-tracked system typically comes with a 5-10 year warranty.
3. Damage in a storm – a solar-tracked system is more likely to be damaged in a storm, depending on the angles of the solar panels at the time of the storm.