Fraunhofer ISE: Higher yields provided by DEGER MLD* technology

 Dual axis solar tracking systems with MLD sensor technology from DEGER can produce more solar energy than photovoltaic systems that track the position of the sun, particularly in the case of low irradiation and diffuse light. This energy increase is greatest when the sun is located at middle to low positions. These are the results of a comparative measurement conducted by Fraunhofer Institute for Solar Energy Systems (ISE), Freiburg, at the Horb-Rexingen solar park.

One thing is clear – all photovoltaic systems are able to obtain good yields at locations with high solar radiation all year round. However, the advantage that MLD technology from DEGER has over astronomically tracked systems can even be seen at such locations, i.e. in the early morning hours and in the evening, when the various positions of the sun are lower than around midday.

The positive effect of DEGER technology becomes even clearer at locations with less than ideal conditions such as, for instance, in Central or Northern Europe. Naturally the middle to low positions of the sun often reduce the yields of photovoltaic systems. In addition, depending on the varying amounts of overcast, there is the fact that diffuse lighting conditions are also comparatively more frequent in such regions than in others.

From March 2011 to February 2013 the solar experts at Fraunhofer Institute for Solar Energy Systems (ISE) compared four different photovoltaic systems at the DEGER solar park in Horb-Rexingen: fixed module surfaces, a single-axis tracked system with MLD technology from DEGER, a dual axis astronomically tracked system and a dual axis system operated with MLD tracking. All four systems were equipped with the same type and number of modules. Within the scope of quality monitoring Fraunhofer ISE determined their yield and power consumption in particular.

Two different methods of analysis were used: the standardization procedure with which all of the values affecting performance – such as cable length, actual module output, inverter efficiency and the like – are taken into consideration, and the standard method where the yield is derived directly from the measurement data after cable losses are taken into mathematical consideration without further corrective calculations.