ecdfan

ecdfan

2p

2 comments posted · 10 followers · following 0

12 years ago @ The Solar Drop @ GoGre... - install unisolar pvl l... · 3 replies · +1 points

Please do no spread misinformation!

There is nothing unique about Unisolar's product - flexible PV is also available from Flexcell, Powerfilm, Xunlight, Ascent, etc. Of course, neither Unisolar's nor any of those other products are priced low enough to compensate for their severe disadvantages vs regular crystalline (significantly-lower efficiency, suboptimal tilt, lower performance and increased HVAC costs due to overheating from lack of ventilation, excessive long-term power output degradation and inferior warranty, harder roof repairs due to the adhesive, the need to clean and/or coat the metal pans before installation, etc, etc).

Traditional solar panels install quite easily and cheaply on metal roof using solutions like S-5! (see www.s-5.com ). Unisolar's installation, on the other hand, is extremely time-consuming (due to the low, 6.3% efficiency for PVL-136) and is typically done on the ground (i.e., you need to be putting a new roof, or the old roof has to be dismantled and the pans cleaned/coated first) - installing the laminates directly on the pans of an existing roof requires a special permission by Unisolar, according to the installation documentation. As a result, there are little savings in the balance-of-system costs. Thus, system installed (or all-in) cost for Unisolar's solution on metal roofs can be significantly higher (on $ -per-KWpeak basis, and, more importantly, on $-per-kWh-delivered-over-the-life-of the-system basis) vs the cost for S-5! clamps with quality Chinese crystalline panels (for example, Yingli/Trina), First Solar's thin-film glass panels, or even SunPower's panels.

Now, why do you say that the Unisolar laminates are durable? First, NREL has shown that Unisolar's a-Si triple junction product degrades in likely violation of its warranty. Second, according to a 2007 ASHRAE report ( http://findarticles.com/p/articles/mi_m5PRC/is_1_... ) , the Unisolar laminates used for the high-profile Science House ( http://www.smm.org/sciencehouse/about/ ) "slid on the roof, causing a ground fault" in 2004.

Finally, while it is true that thin film solar glass panels perform better than crystalline solar glass panels in shady/cloudy conditions (only in the first few years, though, before the higher degradation kicks in), it is NOT TRUE that Unisolar laminates perform better than tilted crystalline glass panels. The reason: the lack of ventilation, the suboptimal tilt, and performance degradation kill any advantages the Unisolar material might have had. There are numerous long-term real-world studies that can show that. Oh, and the rough plastic surface of Unisolar's laminates is a magnet for snow in the winter and dust and soot in the summer (unlike the glass surface of regular tilted panels, which are self-cleaning), thus, further reducing the power output performance in the real world.

So who would want to buy and install this product then? The person who got the installation in the video above (the one sitting with the dog on the bench, about 1min and 34 seconds into the video) has no idea how many kWhs her "solar roof" is generating. Yeah, people like that.

Would it surprise you then that Unisolar's share in the California PV market has been about 0.2% (yes, no mistake here, zero point two percent) over the past two years, measured in kWs reserved and non-cancelled, according to the CSI database? For comparison, Sharp and Sunpower have about 20% share each.

For those who are curious, though, a Unisolar installation guide for metal roofs is available here: http://www.dcpower-systems.com/uploads/products/2...

13 years ago @ Renewbl - renewable en... - Energy Conversion Devi... · 0 replies · +1 points

You sure ECD introduced a new product? How does the new product look like? Why can't you show us a picture? Why do you have a black nonsensical banner instead of a picture of the alleged PowerTilt system?

The following may help you with the answer:

http://ecdfan.blogspot.com/2009/10/racking-of-uni...