Design Considerations for Vertical Bifacial Agrivoltaic Installations

The expected annual energy output of vertical bifacial solar panel arrays was modeled with an eye on how array design attributes affect the output. We considered module height, cell density (single- or double-high racking), inter-row spacing, and inverter connection (rows of modules wired together or separately), and the inclusion of bypass diodes. We observed that these design choices have a substantial impact on the annual energy yield on a per-module basis and per-acre basis. We modeled the instantaneous brightness and shading based on the position of the sun and adjacent rows of modules, which caused nonuniform irradiance due to inter-row shading effects. Based on the irradiance, we calculated current, voltage, and power values throughout a year for different design strategies. Double-high racking, which uses two landscape-oriented modules stacked vertically, offers noteworthy power gains per acre with only a modest increase of inter-row shading. When bypass diodes are included in the module design and improved inverter wiring is used, much of the loss due to inter-row shading is mitigated, and the total power output per acre is nearly doubled, with modules seeing an 80% power increase per acre for 20 ft row spacing, and over 90% power increase per acre for 40 ft spacing.