Dust blown in from the Sahara Desert in northern Africa to central Europe has reduced solar power output in Germany during the week of the Easter holidays, German newspaper Die Welt reports. The power output of solar panels was significantly lowered, especially in the southern state of Baden-Wurttemberg, by the dust clouds, known as aerosols, that the wind carried from the desert across the Mediterranean.

Grid operator TransnetBW had predicted a peak solar PV output of 3500 MW for 30 March, but the dust cloud cut maximum output to 1600 MW. However Transnet also reported that part of the difference between predicted and actual output could also be attributed to regular deviations in forecast models that are unrelated to the dust.

In order to fill the supply gap in the, grid operators were compelled to deploy other power plants, including conventional fossil–fuelled plants. So load management in the grid means that prices can temporarily spike, and lead to an increase in costs to consumers via their grid fees.

The meteorological phenomenon of Saharan dust in central Europe occurs up to 15 times per year and usually leads to dust particles accumulating at an altitude of about 2000 metres. However, the volume and density of dust on this occasion was great enough to cause aerosols fall to ground level, which may have resulted from higher-than-usual air temperatures above the Mediterranean.

Germany’s Meteorological Service recently launched a forecast model that aims to better predict the effect of dust particles on solar PV output, but a major impact on the country’s total renewable power output is unlikely, according to meteorological experts. However they warned that the phenomenon might occur more frequently owing to climate change, and some operators may experience a drop to 70 % of expected output, an effect that would be compounded if the particles are spread over solar panels by rain – so operators should take precautions to keep their installations clean of dust.