See you on the other side
This case study was originally posted on the Kipp & Zonen website.
During the last two decades, photovoltaics (PV) has matured as a technology with a low probability of spectacular efficiency increases. Lowering levelized costs of energy (LCOE) is now achieved rather by shrinking investment and operating costs than by enhancing energy output of PV cells through technological progress.
However, one promising way to significantly boost the efficiency of PV cells is to use the rear side of the modules for electricity generation, too. Thus, reflected or diffused sunlight is added to power generation without extending the footprint of a module. There seems to be a consensus on the high potential of bifacial PV.
However, in the absence of widely established methods to both simulate and measure energy output gains, predictions of efficiency increase through bifacial PV modules vary considerably; this being dependent upon the assumed system setup, the location, surface albedo, the implemented simulation algorithm and further criteria.
What is bifacial PV?
Bifacial PV is slowly finding its way to becoming mainstream by surpassing global energy capacity of Gigawatts of produced energy. With that, a growing basis of collected data on module performance will help to predict efficiency gains more precisely. In this article, we try to give an overview over current research, unanswered questions and technical developments in the bifacial world.
How bifacial photovoltaics work
The main idea is simple. Instead of collecting sun rays on only one side of a PV module, the rear surface catches reflected and diffuse light coming from several angles to generate more electricity. Separate from adjustments regarding rear side material and interconnection, cell technology and geometry base upon proven principles of monofacial modules. That said, bifacial PV is likely to alter smoothly from a promising vision to a widely applied technology with an estimated world market share of up to 30 to 50 per cent within the next ten years.