Bifacial is compelling for several reasons. There’s the obvious power output bonus that comes from harvesting energy from both sides of the same module. Given the right site conditions, decent albedo and an optimized module design, bifacial will boost performance by a significant margin. When bifacial is integrated with increasingly innovative and optimized balance of systems (BOS) configurations, the boost in array performance could go from incremental to game changing.
This performance acceleration also fosters a parallel reduction in the entire BOS ecosystem – and the capital costs required to build it out. If bifacial means you only need 75-80% of the number of monofacial modules that would have been required for a multi-hundred-megawatt solar field, the amount of all of the other components, systems and costs – inverters, trackers, cables, land, labor and the like – can also be reduced. The higher the power density of the plant, the less BOS you need per module. While there are always site-specific factors that can confound these savings, developers are already selecting and sizing sites to optimize for these bifacial savings.
While the promise of bifacial systems is exciting, it is not without risk. Before the utility-scale solar pipeline fills with projects modeled for bifacial modules, the modeling itself needs to be standardized. We need standardized module ratings and tightly prescribed product specs, as well as fully baked implementations of bifacial parameters in industry standard modeling software, such as PVsyst. We also need to know how the modules integrate and operate with the balance of systems, so we can assess the impact of bifacial on the overall power plant. This also involves performance measurement, estimation, verification and other testing by independent engineers, so I as a developer can have a defensible certainty about how the plants will perform and can present that information to prospective long-term owners. Thankfully, these efforts are well under way, and we’ll have a much better handle on bifacial risk assessment within the next year or so.
Of course, bifacial is not the only module improvement coming to market. There are larger cells, shingled and half-cut cells, and modules with rearranged buses. There’s an explosion of product innovation, more than we’ve seen in a long time. Beyond that, BOS companies like Nextracker are working with the module manufacturers to optimize bifacial integration, using tweaks such as higher elevations, optimized module mounting, and other albedo enhancements. When you piggyback all these innovations, we have years of runway of just working out the optimal applications of the technology.
To be honest, as a company sitting on more than a gigawatt of contracted solar project assets that will probably be sold to a new owner and going into construction by this time next year, we are very eager to push the verification of as many of those innovations as possible, as soon as possible. Some of these upsides have already been baked into our PPA prices on those projects, so we are eager to prove them out in order to preserve our own margins. Other improvements such as BOS innovations and new ways of optimizing bifacial aren’t yet part of our base case and represent an opportunity for us to improve margins or more likely lower PPA prices. For every one of these new innovations that we can’t get third-party verified and put in our model, by the time our assets are sold to long-term owners, we lose money. There’s a sprint to try and capture not just the baseline (swapping the modules), but the engineering optimization efficiencies, the BOS innovations, and even the balance of module optimizations that people are doing with these new technologies.
One of the underplayed upsides of optimized bifacial technology is the tremendous impact it will have on solar’s ability to expand into new power markets – and the added level of sophistication that developers will need to take advantage of those new markets.
We see the move to an entirely bifacial industry opening up greater and greater addressable volume in the global power markets. Much lower solar irradiance zones will achieve wholesale market parity on the utility price points – without renewable portfolio standards or other regulatory kickers and subsidies. Solar will be a regular player in these markets like gas or coal or anything else, and that’s a huge opportunity. These markets are deep, they’re liquid, and they’re addressable – although they may take a bit more sophistication, financially and structurally, to be successful from a developer’s standpoint. That’s the future that bifacial helps make possible.
Sheldon Kimber is CEO and cofounder of Intersect Power, a U.S. utility-scale solar developer with a pipeline of more than 1.2 GW of contracted assets. Intersect is a partner in the new bifacial PV tracker test field, located next to NEXTracker headquarters in Fremont, CA.
The views and opinions expressed in this article are the author’s own, and do not necessarily reflect those held by pv magazine.