The albedo contribution may become significant with littles systems (BIPV) without shades on the ground level, and large plane tilts.

Its contribution goes with (1 - cos(tilt)) / 2, i.e. 0.03 for 20° tilt, 0.067 for 30° and 0.5 for 90°.

For a big system in sheds (rows), the effect will be very low, because only the first row "sees" the albedo. Therefore there is a shading factor of (n-1)/n on the albedo contribution.

Now if you increase the albedo contribution, you will increase the GlobInc (result of the transposition on the tilted plane), but also increase the Linear shading loss by about the same amount.

Therefore you will get about the same yield (E_grid), but diminish the Performance Ratio, as the PR is referenced to GlobInc.