Ground sculpting to enhance vertical bifacial solar farm output

Abstract

The prospect of additional energy yield and improved reliability have increased commercial interest in bifacial solar modules. A number of recent publications have quantified the bifacial gain for several configurations. For example, a standalone, optimally-tilted bifacial panel placed over a flat ground (with 50% albedo) is expected to produce a bifacial energy gain of 30% (per module area). In contrast, for a panel array in a solar farm, self and mutual shading reduce the bifacial gain at the same tilt to 10-15% (per farm area). Bifacial gain is negligible for vertical arrays--although the configuration is of significant interest, since it can prevent soiling. Here, we calculate the bifacial gain of a solar farm where vertical arrays have been placed over sculpted/patterned ground. We conclude that vertical panels straddling (upward) triangle-shaped ground maximizes the energy output. For this optimum configuration, the bifacial gain can approach 50%, especially for regions with moderate to high cloudy conditions. The enhanced output, along with reduced soiling loss and lower cleaning cost of the ground sculpted vertical bifacial (GvBF) solar farm could be of significant technological interest, especially in regions such as the Middle East and North Africa (MENA), particularly susceptible to significant soiling losses.