I do have a 50kw ground-mount of mono-facials alongside 300kw of bifacials (both @ similar azimuth and tilt).. After calculating both arrays to watts/sq. ft, the bi's outproduce the monos by 30% in midwinter with snow ground cover and both arrays 100% clear. I spec only bifacials for ground mounts as a result.
On Sun, Dec 21, 2025 at 3:53 PM Zeke Yewdall via RE-wrenches < [email protected]> wrote: > We've been using bifacial modules for ground mounts in Colorado this last > year and they seem to be doing very well. No hard data with a side by side > comparison with a regular module, but it seems that they generate better. > We use snow as our reflection surface. I've also heard anecdotally that > they are good in cloudy conditions in the pacific northwest where you > aren't collecting much direct beam radiation, but again, I don't curently > have side by side monitoring data. PVwatts claims a 5 to 10% increase in > most climates, and less sensitivity to exact orientation, which could also > help with off grid sites. It also seems like the dark backside heats up a > little faster on grounmounts and melts snow and ice off just a little > faster than regular modules. > > As far as backside shading goes. The back side behaves just like the front > side from small hard shadows (like from racking). A significant drop in > production. But diffuse light, which is almost always what the back side > is receiving, should be less affected by racking shading -- but I still > think it would make sense to try to reduce racking shading of the back side. > > The biggest thing that concerns me about bifacial modules is that most of > them are not tempered glass. Two 2mm layers of heat strengthened glass is > supposed to be stiffer than one layer of 3.2mm tempered glass, but still > less impact resistance if you are in any potential hail area in the 1" to > 2" range (higher than 2" is liable to break even the tempered glass modules > anyway). Other than that, I don't see any downsides, as they are usually > cheaper per watt than regular modules too. A lot of people were using them > on flush roof mounts because of the cheaper price, though you get zero > benefit from the bifacial aspect there. > > Z > > -- > Zeke Yewdall > PV Engineer > NABCEP #031508-89 > [email protected] > 303-523-3592 > _______________________________________________ > List sponsored by Redwood Alliance > > Pay optional member dues here: http://re-wrenches.org > > List Address: [email protected] > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > There are two list archives for searching. When one doesn't work, try the > other: > https://www.mail-archive.com/[email protected]/ > http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org > > List rules & etiquette: > http://www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > http://www.members.re-wrenches.org > > -- *Kirk Herander / **[email protected] <[email protected]>* *Owner|Principal, VT Solar, LLC* *Celebrating our 34st Anniversary 1991-2025!!* dba Vermont Solar Engineering 802.559.1225
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