Solar Power » Technologies

Ground-mounted Systems

Using fields rather than roofs to place the solar modules on, it is possible to construct utility-scale power plants.

Fixed Mounting

Solar field with fixed mounted modules Free-standing modules can be mounted such that they face the best angle. Again, wind speeds need to be taken into account. With some mounting systems, the manufacturer advises to place the modules flat on the ground during wind storms.


The modules are usually configured in rows. In order to avoid one row causing a shadow on the following row, the rows have to be placed at a fair distance, which will largely depend on the latitude of the site. We have provided more details on this effect of self shading.


How much space is required? About one third of the space can be physically covered with modules. Consequently, for 1MW of name plate capacity a field of 2 hectares is required. Sites that are closer to the equator may need less space.



Tracking Devices

Ground-mounted solar installations can make use of tracking platforms that can tilt the surface along one or two axes with the help of a motor.


Automated tracking can be passive or active. Due to thermal inertia, passive systems tend to be slow in changing from the sunset position to the sunrise position. Active trackers either calculate the current position of the sun from first principles, or use light sensors that will point the modules to the brightest point in the sky, not necessarily the sun - especially when it is cloudy. In active systems, the motor itself is connected to a device that determines the angle of the sun.

Horizontal Axis Tracker

The modules rotate around a horizontal axis, tracking the sun from south to north from winter to summer.

Horizontal axis tracker

Vertical Axis Tracker

The modules are at a fixed tilt angle mounted on a platform rotating around a vertical axis following the sun from east to west.

Vertical axis tracker

Tilted Axis Tracker

The modules are mounted on a tilted bar that rotates. The modules are following the sun from east to west daily.

Tilted axis tracker

Dual Axes Tracker

Dual-axes trackers allows tracking along both axis - east-west (daily) as well as north-south (seasonal tracking)

Dual-axis tracker

Energy Yield Gain thru Tracking

Tracking will always result in a higher energy yield. The amount of the boost however is very much dependant on the location. Generally, locations with a higher proportion of direct sunlight such as Spain or Finnland will benefit more from tracking than locations with a high proportion of diffuse light such as Germany.

However, the gain in the energy yields comes at a cost, as the tracking mechanics and associated increase in maintenance add to capital and operational expenditure. The energy requirement for the motors on the other hand is negligible.

Above diagram illustrates gains achieved by using trackers for a site in Zimbabwe in comparison to fixed mounting with optimal tilt angle of 30°. The annual performance gain achieved by horizontal-axis tracker is over 20%. Additional gains from the second axis are only 6%. Whether tracking is the best solution for you location, please contact us for advice.

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