The racking of Unisolar laminates

United Solar announced their tilted racking solution today [there was no picture in that press release - read below about the source of the picture on the left]. According to the press release, the "UNI-SOLAR PowerTilt rooftop solar system is the newest member of United Solar's PowerLine of products," implying that that there must have been other PowerLine products already. Weird, as a google search for the mysterious "PowerLine" results in no hits on either Unisolar's or ECD's sites today (other than the press release, of course).

 

According to ECD's CEO, this PowerTilt rack is "a new" product. That is strange, as well. He already showed an installation with this product (or a product that appears very similar) on Slide 10 in the Feb 9th, 2009 earnings call presentation. While Unisolar has not provided any specs or pictures of the product, tilted rack-mount solutions for Unisolar laminates date back to at least 2006 (for Kalzip's tilted SolarClad see page 9 of their 2006 brochure). Most recently, Centrosolar made a somewhat premature announcement in July this year, claiming that they would announce the "TF Multi Professional" at the EUPVSEC in September with system availability in the same month (the certification process was expected to be finished by then). That system was supposed to consist of "5600 mm long and 455 mm wide folded aluminium profile sheet onto which thin-film laminates are permanently applied at an inclination of eleven degrees." However, in September Centrosolar announced instead the SunPAC crystalline package. As of today, no trace of "TF Multi Professional" can be found anywhere on Centrosolar's web site. Even more strange is that the Centrosolar system (and today's Unisolar system, for that matter) appears a spec-by-spec copy of Suntimes Solar's product, LBM-PVL (latest datasheet for which is dated December 2008). Suntimes actually have been installing their LBM-PVL since 2007 (see the Nibra installation, for example). The picture above comes from Suntimes' G.U.T installation.

 

So, how is Unisolar's "new" solution different from Suntimes' 2007 solution? Maybe someone who is visiting booth 1111 at the 2009 Solar Power International can shed some light...

 

In the mean time, let's see whether this product makes sense. The major "selling point" of Unisolar's laminates until now was that they do not require a rack - they can be glued directly to the roof - which can save between 10c and 40c per Watt in balance-of-system costs, depending on the roof, type and size of installation, etc. Unfortunately, gluing to a flat roof creates a few BIG problems. First, the laminates cannot be removed easily which makes them a hard sell for Power Purchase Agreement providers (and their investors) who lease (do not own) the roofs on which they install the PV systems. Second, the glued-on laminates (basically, tilted at 5 degrees or so) do not face the Sun optimally, which, depending on the system's geographic location, leads to moderate to severe kWh/kW underperformance vs optimally tilted panels (the glued-on Unisolar laminates underperform the tilted Unisolar panels by about 20% in California, for example, as detailed in this post), leading to higher LCOE costs. Third, the laminates heat up the roof due to lack of ventilation (Unisolar's laminates have effective solar reflectance of just 30, see this post) , which could lead to increased HVAC electricity consumption, and thus, a reduction in the net electricity supplied by the PV system (anywhere between 1% and 10%, depending on the roof insulation). Fourth, roof repairs become difficult as the laminates are hard to unglue. Fifth, fire hazard is "an attention point" as the laminates touch the roof surfaces directly (see page 16 in this report). All these issues combined might, in some cases, more than offset the "rack savings."

 

So, yes, PowerTilt addresses all of these isshttp://ecdfan.blogspot.com/2009/10/racking-of-unisolar-laminates.htmlues. The system can be now be removed relatively easily. The tilt has improved, and even though the 11-16 degree tilt is still not optimal in most locations, it still leads to up to 10% improvement in kWh/kW yield vs no-tilt laminates (in San Francisco, for example, a change in tilt from 5 degrees to 16 degrees results in 7% improvement in kWh/kW yield, while the change in tilt from 5 degrees to 30 degrees results in 11% improvement in kWh/kW yield, according to the PVWatts v1 calculator). Ventilation has improved (not as good as in glass tilted panels, but the hot air can now at least escape on the side and aluminum is a good heat conductor) . Fire hazard is substantially reduced, as aluminum oxide is not flammable (and ventilation is improved). Finally, roof repair is now much easier.

But these improvements come at a cost - the cost of the aluminum frame. MetalsDepot today quotes 3/32-inch aluminum sheets for about $60-67 per square meter. Unisolar's PVL-136 is 6.3% efficient on module level, meaning one square meter worth of laminate is rated a bit below 63 Watts (PVL-144 is a bit below 67 Watts). So, the aluminum rack will likely add about $1 per Watt (the rails and the fasteners would be extra). Experts in aluminum pricing are welcome to provide more precise estimates.

 

So does this product make sense today? Let's assume that Unisolar's installed system cost (for the current no-tilt glued-on solution) can be lowered to $4 per Watt (see here). The new aluminum rack "solution" then would increase the cost to at least $5 per Watt, but because the kWh/kW yield will increase by 10% as well, the effective "new" system cost is just about $4.50 per Watt. So now Unisolar can offer a $4.50-per-Watt regular rack-mounted PV system that is functionally equivalent to SunPower's T5 or First Solar's non-penetrating rack-mounted solution. That is a problem! First Solar's rooftop system installed cost (as well as the cost of rooftop systems with certain Chinese crystalline panels) is now below $4 per Watt. The new Unisolar solution will be functionally equivalent, yet it will cost 10% more. Not good - it will be a hard sell in the very competitive commercial rooftop PV market where achieving the best return-on-investment is crucial.

 

In other words, PowerTilt makes Unisolar's laminates more marketable but at (likely) prohibitively-higher cost, thus, it does not fundamentally resolve the main competitive issues, as discussed here and here. No wonder that Centrosolar have been quiet since July and that Suntimes show no references dated 2009.

 

Comments (and especially pictures and specs of the "new" product) are more than welcome!