Impact of a fire burn on solar irradiance and PV power

Global and direct irradiance observations were compared with those from analogous clear days, as well as with values obtained from a clear sky model, in order to estimate the reduction in irradiance due to the smoke plume. The results showed that global irradiance was reduced by 6.5% and direct irradiance by 9% during a 140 min afternoon period, with one-minute reductions of up to 26% and 32% respectively. The spectral global irradiance showed that the smoke had the greatest impact in the wavelength range from 400 to 500 nm. A spectral analysis of the impact of smoke on six different PV technologies revealed that the least impact was on the mono-silicon cells used in this study. The resulting effect of solar power output was an overall reduction of 7% during the study period and a peak reduction of 27%.