SunMine and SnowMan

Kimberley is known for its sun but also its ski hill and plenty of good snow in the winter.  What is the effect of snow on the solar plant output?  Will the plant be shut-off in winter?

On the contrary, snow on the ground and low temperature improve the performance of a solar system  and snow will not stay long on PV panels.

To prove it and measure other solar data, we installed a test system on site composed of a weather station measuring the sun (pyranometer), ambient temperature (thermometer) and wind speed (anemometer) and in parallel two PV arrays: one on a vertical axis tracker (VAT) and one on fixed racks.  In high latitudes, such as Kimberley, the best annual energy yield is obtained if the panels are set at a steep angle.  (56°  for the VAT and 45° for the fixed).  The description and results of the test can be found here.

Effect of snow  

PVs warm up when they produce energy. A good proxy to find out if the PV is covered with snow is to correlate the PV temperature measured at the back of the PVs with the solar radiation measured by the pyranometer on the weather station.

The figure  plots the temperature (Y-axis vs radiation X-axis) during the day for the entire test period (more than 1 million records) for the arrays on the VAT. If the snow covers the PV and prevents it from operating, it will appear as high radiation level and negative temperatures (the zone in dark blue below the x-axis).

In total, there were less than 0.2% of these occurrences, which supports the conclusion than snow is not an issue for the PV system. Three reasons for this: steep panels slope (56 °) , glassy surface of the PV modules and the fact that when the PV starts operating the temperature increases and the snow melts down.

The snow on the ground reflects the sun and increase the solar yield and the low temperature increases the overall PV electrical efficiency.

In conclusion, far from being a hindrance , SnowMan is SunMine’s best friend.