Changes in solar PV output due to water vapour loading in a future climate scenario

Under a future climate, it is shown that the total atmospheric water vapour will increase over present levels. Water vapour has several distinct absorption bands in the visible and near-infrared parts of the spectrum, which is critical for PV conversion. The sensitivity of current world-leading c-Si, thin film and perovskite solar cells to the solar spectrum under different water vapour loadings is investigated. Semiconductors with bandgaps above 1.4 eV are more resilient to increases in atmospheric water vapour due to the avoidance of two large absorption bands in the near-infrared. Global changes in atmospheric water vapour are then taken from the HadGEM2-ES climate model under the RCP8.5 scenario, and used to determine the changes in PV output for clear-sky conditions for crystalline silicon (c-Si) and amorphous silicon (a-Si) solar cells. For some regions of the world, a decrease in power output of up to 3% for clear-sky conditions is seen for the spectral response of the current world-leading c-Si cell due to increasing water vapour, whereas a-Si performs better with a global power output decline of less than 1%.