Solar concentrators known to the inventor use mirrors on a relatively large surface to reflect sunlight onto a focal zone where a converter is located.  The converters convert the solar energy into another form of useful energy such as electricity or heat.  The surface is curved or parabolic in shape so that the incident sunlight is directed towards the corresponding focal zone.  The reflective surface is usually formed of a single curved mirror or an array of curved mirrors fixed on a disc or trough shaped member. 
As the surface needs to be relatively large in surface area, the disc or trough shaped member must also be large in size.  Due to the size, it is difficult to fabricate such member with a portion thereof having a shape corresponding to that of the curved or parabolic reflective surface.  Moreover, it takes considerable care to shape the mirror/mirrors so that they can be fitted together to form said shape.  To fix them to the portion to form the reflective surface also requires considerable skill.  Accordingly, the costs of manufacturing the prior art solar concentrators are generally high. 
The mirror/mirrors are usually coated with a clear polymer material to protect them from the environment.  But the material is affected by the ultra violet (UV) rays and it tends to degenerate progressively in time.  The glass mirrors are susceptible to damage by hail storms. 
If the mirror or some of the mirrors are damaged the concentrator would need to be removed from service so that repair work can be carried out. 
Satellite antennae are concentrators for concentrating radio wave energy from satellites.  They also have a curved or parabola shaped metallic disc for concentrating or reflecting radio wave energy towards a low noise blocking converter (LNB) located at a focal zone over the disc.  Thus satellite antennae also have some of the difficulties relating to the use of a large reflective surface in the solar concentrators. 
The prior art concentrators are relatively high and are susceptible to damage by high wind.  In addition, they are relatively heavy and as such require a relatively strong support structure and a relatively high powered motor to cause them to move.