A new study shows how neural networks and random forests can predict solar irradiance from 300‑1100 nm with great accuracy. Researchers compared two approaches: one uses real aerosol optical depth (AOD) measured at specific wavelengths, the other generates synthetic AOD using the Ångström exponent. The synthetic‑AOD model outperformed the real one, achieving a coefficient of determination of 0.979 versus 0.967. This precision allows calculation of the spectral mismatch factor (SMF) for various photovoltaic technologies. CuInGaSe and monocrystalline silicon cells exhibit a stable SMF, while perovskite cells are more sensitive to spectral variations. In practice, better knowledge of incoming light helps optimize solar cells and boost overall renewable energy efficiency.
The spectral mismatch factor (SMF) measures the difference between a photovoltaic panel’s spectral response and the solar spectral distribution. A high SMF indicates that the cell is not fully exploiting available light, reducing efficiency. Accurate SMF measurement requires detailed knowledge of solar irradiance from 300 to 1100 nm, as different PV technologies (monocrystalline silicon, CIGS, perovskite, etc.) have distinct spectral sensitivities. Atmospheric aerosols alter the spectral distribution by filtering light; their optical depth (AOD) is therefore a key parameter. The Ångström exponent allows modeling AOD over a continuous range, eliminating the need for measurements at many wavelengths. Random forests and neural networks, trained on atmospheric variables (temperature, humidity, pressure) and synthetic AOD, have shown to predict spectral irradiance with a mean error below 5 %. This approach reduces reliance on expensive measurements and improves SMF estimation accuracy, directly impacting solar installation optimization under varying climatic conditions.
