Optimize Bifacial Installation

Some of the best practice recommendations to optimize your bifacial installation and achieve increased ROI and lower LCOE are as follows:

• Site selection: The cost of land affects how bifacial can be optimized. For places where land is scarce and expensive, panels should be laid flat on the ground to ensure maximum energy collection over a given land area. However, where land is cheap, bifacial modules can have optimal spacing and therefore higher yields. Also, bifacial yields are greater where the diffuse light energy is greater, which means at higher latitudes the bifacial yield will be greater than at lower latitudes.
• High albedo: The environment selected should have a high albedo. Desert sand is a good option. The best option is white concrete or highly reflective roof foil. Snow and ice also has very high albedo.
• Panel height: This will vary from site to site, but 1 meter has provided good benefit to cost ratios. Increasing panel height requires other variables to be measured as well, such as wind speed and lift from the tilt and therefore requires stronger ground mounts.
• Tilt: This will vary from site to site, but generally 2~15 degrees more than the monofacial tilt has been shown to be effective.
• Row distance: Again, this will vary from site to site, but 6 to 8 meters row distance has been shown to produce good results. Of course, the cost of land or the available space must be considered, and if the cost of land is too great, then a greater row distance will increase your LCOE. Ideally, somewhere that land is very cheap can be used to increase row distance cost-effectively.
• Greater MPPT density: Using string inverters with more MPPTs (maximum power point tracking) is an effective way to reduce string mismatch and ensure efficient performance. The more MPPTs per watt the better.
• Single-axis tracker: Researchers from the Solar Energy Research Institute of Singapore have concluded that bifacial installations with single-axis tracking can increase energy yield by 35% and reach the lowest LCOE for most of the land area on the planet. Although dual-axis trackers achieve the highest energy generation, their costs are still too high and are therefore not as cost-effective. The researchers wrote: “In general, with the same mounting structure, bifacial configuration outperforms monofacial configuration. Tracker configurations outperform fixed-tilt configurations significantly, with dual-axis tracker installations having a marginally higher yield than one axis.”

Cost analyses have shown that the cost of equipment and installation of a bifacial PV plant will be around 5% higher than a comparable monofacial plant. Furthermore, the data shows that the cost of adding a single-axis tracking system for optimal yields adds another 10% to the equipment and installation costs over an equivalent installation with no tracking.

In summary, the industry is currently still struggling to manage the variables of predicting the output of bifacial modules, and also to manage the costs of optimizing the power produced by bifacial modules. These obstacles are being slowly overcome, however, with each advance in data and technology.