While it appears sound that large hurdles, such as clouds and buildings can obstruct sunlight from reaching solar cells, but smaller objects, such as dust and leaves can create similar problems too. The understanding how incoming radiation influences power output is essential to optimize photovoltaic technology, which converts light into electricity and contributes significantly toward transition to green energy.
A publication in the Journal of Renewable and Sustainable Energy discusses how different shade conditions influence performance of single solar cells and two-cell systems arranged in series and parallel.
“In real world situations, photovoltaic cells are sometimes blocked by obstacles, which alters the amount of incoming light significantly,” stated the author of the paper. The deterioration effects make power optimization challenging and result in significant amount of power loss.
Photovoltaics arranged in a series form a single path wherein electrons move from one cell to the other. On the other hand, photovoltaic cells arranged in parallel provide two lanes for electrons to flow, and then recombine. In practical applications, networks of solar cells are arranged in parallel and series to increase the output current and power capability.
The decline in output current of two cells or single cell arranged in parallel is almost same to the ratio of shade to sunlight, found the researchers. However, if two cells are arranged in series, there is excess rise in temperature and power loss, which can lead to further degradation of output.
A number of factors, including shadows on different cells of the arrangement, shadow area, and connection of cells and modules, may impact performance, indicates the study.
In fact, previous studies have examined the effect of shade on large photovoltaic systems, but have largely overlooked single cells and simple energy systems.