Soil irradiance test curves. (left) The effect of three solar park designs on the ground irradiance using the white bifacial module. The east-west solar park is labelled “EW NL” and shown with a solid red line; the “S NL” stands for the south-oriented solar park in NL, plotted with long, green dashes; and the south-facing solar park in Spain “S ES” is represented by the short, blue dashes. (right) The effect of partially transparent, green dashes, and fully opaque, solid red line, on the ground irradiance for the south-oriented solar park in the Netherlands. In both graphs, the grey solid line represents the ground irradiance guidelines as proposed for the Netherlands.