Quality control of tilted solar irradiance: Asystematic and generalizable procedure

Solar irradiance on tilted surfaces is a key input for photovoltaic energy production. Yet, most existing quality-control procedures have focused almost exclusively on horizontal measurements, largely overlooking tilted-plane data. In this study, two novel methods are proposed to assess the quality of solar irradiance on tilted surfaces. The first relies solely on solar and surface geometry, combined with the historical maximum ground albedo at the site, to establish acceptable upper and lower limits. The second is based on a clear-sky model, accounting for its known uncertainties and the historical maximum ground albedo, to define similar limits. Both methods are validated using four years of 1-min data from surfaces with various tilt angles in southern France. Results indicate that the geometry-based method proves simple and effective, while the clear-sky–based method provides tighter envelopes at the cost of requiring more detailed inputs. Together, these tools enhance the reliability of solar data for photovoltaic applications.